CA1089947A - Apparatus for indicating the farthest advance position of a bi-directionally movable medium - Google Patents
Apparatus for indicating the farthest advance position of a bi-directionally movable mediumInfo
- Publication number
- CA1089947A CA1089947A CA286,427A CA286427A CA1089947A CA 1089947 A CA1089947 A CA 1089947A CA 286427 A CA286427 A CA 286427A CA 1089947 A CA1089947 A CA 1089947A
- Authority
- CA
- Canada
- Prior art keywords
- count
- signal
- counter
- pulses
- medium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
- G11B27/11—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information not detectable on the record carrier
- G11B27/13—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information not detectable on the record carrier the information being derived from movement of the record carrier, e.g. using tachometer
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/02—Control of operating function, e.g. switching from recording to reproducing
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/18—Driving; Starting; Stopping; Arrangements for control or regulation thereof
- G11B15/46—Controlling, regulating, or indicating speed
- G11B15/54—Controlling, regulating, or indicating speed by stroboscope; by tachometer
Abstract
ABSTRACT OF THE DISCLOSURE
Apparatus for indicating the farthest advance position of a bi-directionally movable medium is provided with a pulse generator mechanically coupled to the medium to generate pulses corresponding to incremental movements of the medium in either a first or second direction. The actual direction in which the medium moves is represented by respective first and second signals.
A counter incrementally changes its count in response to each gen-erated pulse when the medium moves in, for example, the second direction, and the counter reverses the direction in which it counts when the medium moves in the first direction following medium movement in the second direction so that the counter incre-mentally is restored to an initial count. Once the initial count of the counter is restored, an output farthest advance signal is produced indicating that the medium has reached its farthest advance position. In one embodiment, the apparatus is used to indicate the farthest advance of a movable web. When the web is reversed, the counter is decremented from an initial predetermined count. When the web subsequently is moved forward, the counter then is incre-mented. Once the web reaches the farthest advance position previ-ously occupied prior to reverse movement thereof, the counter con-currently reaches its initial, predetermined count.
Apparatus for indicating the farthest advance position of a bi-directionally movable medium is provided with a pulse generator mechanically coupled to the medium to generate pulses corresponding to incremental movements of the medium in either a first or second direction. The actual direction in which the medium moves is represented by respective first and second signals.
A counter incrementally changes its count in response to each gen-erated pulse when the medium moves in, for example, the second direction, and the counter reverses the direction in which it counts when the medium moves in the first direction following medium movement in the second direction so that the counter incre-mentally is restored to an initial count. Once the initial count of the counter is restored, an output farthest advance signal is produced indicating that the medium has reached its farthest advance position. In one embodiment, the apparatus is used to indicate the farthest advance of a movable web. When the web is reversed, the counter is decremented from an initial predetermined count. When the web subsequently is moved forward, the counter then is incre-mented. Once the web reaches the farthest advance position previ-ously occupied prior to reverse movement thereof, the counter con-currently reaches its initial, predetermined count.
Description
BACKGROUND OF THE INVENTION
This invention relates to apparatus for indicating the farthest advance position of a bi~directionally movable medium and, more particularly, to solid-state electronic farthest advance apparatus which can be used, for example, in conjunction with a reversible web without requiring a direct sensing of the condition of the web.
In many processing systems, such as a web processing system, i-t often is necessary to bi-directionally move the web relative to a processing station. If the web is moved normally in a forward direction, it is desirable, once the web is reversed, to indica-te when the web has been returned to its previous ~arthest advanca position.
One type oE web processing system wherein knowledge of the ~arthest advance position of the web is desirable is a dictat-ing ~ys tem. As one example, in a central dictation system, a central recording unit is adapted to be connected to individual ones of plural remote dictate stations. Once this connection is obtained, an operator at the remote station can dictate messages ~0 on-~o the recording medium at the central recording station and c~n control various functions, such as dictatel rewind, playback, and the like. In many applications using this central system, a :
~ubsequent operator at another remote station can dictate messages on~o ~he recording medium ~ollowing the completion o:E the d:lctation ~p~ration by the previous operator. It has been found that, in ~me in9tances, the last action taken by the previous operator pri4~ to disconnecting his remote station from the central record-ing station is to partially review his dictated message. Hence, at the time of disconnection, the record medium has not been fully restored to the ~arthest advance position corresponding to the end -. .
~, .
~ g~of the dictated message. Therefo~e, to prevent the su~sequent operator from dictating his message over the remaining porti~n of the previously dlctated message, it is necessary to return the medium to its farthest advance position prior to effecting a connection between t~e remote station of the subse~uent operator and the central recording station.
In a central dictation system of the type disclosed in U. S. Patent No. 3,823,274, assigned to the assi.gnee of the instant invention, the recording medium i~s an endless loop of magneti~c tape :~
capable of being stored in serpentine folds in a housing. A record/~
playback transducer is provided .i`n the hous~ng and the tape is driven bi-directionally past the transducer. During forward move-men-t oE the tape, as in a recording mode, the tape is drawn taut over various guide rollers. However, when the tape is reversed, .
this tautness is relaxed and a loop is formed ~etween a set oE
guide rollers. Consequently, to determine whether the tape has reached its farthest advance position, it merely is necessary to .
sense the tautness of the tape. Thus, when all of the rewound tape has been transporteA in the forward d~rection, as duri`ng the playback of a previously recorded message, the tape once again is taut. As diclosed in U. S Patent No. 3,823,27~, the tau-tness of the tape i9 sensed by a mechanical switch that is closed when ~h~ t~p:e i9 rewound to ~orm the loop and that is opened when the ~ape is -taut, thereby indicatlng that the tape has been restored tQ its ~arthest advance positi~on.
~ 1-though th.is technique of using a mechanical swi.tch to detect the tape tautness as an indi.cation oE the farthest advance position is sati.sfactory for a central system provi.ded with an endless loop of tape, it is not completely successful when used with other recording media. For example, lf the recording - .. -.
medium is a magnetic tape housed in a casset~e, reversal of the tape from its farthest advance position does not result in the formation of a tape loop as described above. Although the amount of tape payed out from the cassette supply reel onto the take-up reel can be sensed by measuring the diameter of the take-up reel and then sensing when this diameter is reduced, as during rewind, and subsequently restored to indi-cate that the tape has returned to its Earthest advance position, such reel-measuring is highly inaccurate.
As another example, if the recording medium is a belt that is scanned by a traversing record/playback head, a review operation is performed by movin~ the head baàkward relative to tho belt. ~ence, Earthest advance cannot be detected by sensing the tautness or slackness of the medium as d~sclosed in the afore-noted patent.
OBJECTS OF T~E INVENTION
Therefore, it is an object of the present invention to provide improved apparakus for indicating the farthest advance position of a bi-directionally movable medium.
~0 Another object o~ this invention is to provi~de Earthest advance indicating apparatus which can be used in a record~ng system and which need not rely upon the format.ion of a loop in ~he recording medium.
A ~urther object of this invention is -to provide farthest advanGe indicating apparatus ~or use in a d.ictation system oE the type using a web o~ recordln~ medium.
An additional object oE th~s invention is to provide ~arthest advance indicating apparatus where~n solid-state elec-tronics are used to indicate when a recording tape is reversed from its farthest advance position and when that tape has been restored to its farthest advance position.
.''~', ' ' ' ~L8~5~94~
Yet another object of this invention is to provide apparatus for use in a dictation system employing a magnetic tape cassette wherein the farthest advance position of the tape is indicated.
Various other objects, advantages and features o~ this invention will become readily apparent from the ensuing detailed discussion, and the ``
novel features will be particularly pointed out in the appended claims.
SUMMARY O~ THE INVENTION
Apparatus for indicating the farthest advance position of a medium bi-directionally movable by a transport mechanism is provided with a pulse 1~ generator operable as a function of the movement of the medium to generate pulses as the medium moves either in a first or second direction, a counter eouplecl to the pulsc~ generator and responsive to each pulse so as to in-el~em~ntally change its count from an initial count, for example, to reduce its count, when the medium moves in the second direction and then to increase ~
its count in response to each pulse when the medium reverses direction so ~ `
as to move in the first direction, and an output device coupled to the counter and responsive to the restoration of the counter's initial count to produee a farthest advance signal indicating that the medium llas returned to its ~arthest advance position.
Accorcling to a broad aspeet of the present invention, there is provi~lecl apparatus for indicating the farthest advanee position oE a meclium ~i-directionally movable by a transport meehanism, eomprising: means Eor pr~vi~lng a first signal when said transport meehanism is aetuated to move ~aicl medillm in a ~irst direction; means for providing a seeond signal when s~id transport meehanism is aetuatecl to move said medium in a second direction opposi~o to said ~lrst direetion; pulse generating means operable with said tr~nsport mechanism to generate pulses representing the amount that said medium moves either in said first or in said seeond direetion; bi-directional counting means seleetively responsive to each generated pulse to ineremental-ly change the count thereof in a first or second direction; gating means forcoupling said generated pulses to said counting means when said medium moves in said second direction so that said counting means incrementally changes its .:
~ ' :
~.~8~9~7 count from an initial count and in a first direction and for coupling said ~.
generated pulses to said counting means when said medium moves in said first direction following movement in said second direction so that said counting means incrementally changes its count in a second direction so as to be restored to said initial count; gate control means responsive to said first and second signals and to said generated pulses for energizing said gating means when said first or second signal is initiated in non-coincidence with a generated pulse and for maintaining said gating means energized if said first or second signal terminates but said pulses continue to be generated; .
and output means for producing a farthest advance signal when said counting means is restored to said initial count and for maintaining said farthest advance signal unt~l said medium subsequently is moved in said second direc-tion.
BRIEF DESCRIPTION OF`THF. DRAWINGS
The following detailed description, given by way of example, will best be understood in conjunction with the accompanying drawings wherein:
FIGURE 1 is a logic diagram of the farthest advance apparat~ls in accordance with the present invention; and -~a- :
: .
FIGURE 2 is a schematic diagram of a circuit used in the farthest advance apparatus shown in FIGUR~ 1.
DETAILED DESCRIPTION OF A ~REFERRED EMBODIMENT
Although the present invention can be used to indicate when virtually any bi-directionally movable device is moved awav from the farthest position it last occupied and then is restored to that ~arthest position, the following description relates to the use of this invention with a bi-directionally movable web.
Fur~hermore, as will now be described with reference to FIGURE l, ~:
this web here is a magnetic recordi.n~ tape T bi-direationally driven between, for example, a supply reel and a kake-up reel.
To best illustrate the novel aspects o~ farthest advance indi-cating apparatus lO, it will ~e assumed that tape T is housed in a cassette 12 and is used in a recording/playback device, ~uch as a dictation device. Although not necessary to a full understanding of this invention, the dictation devi`ce may be included in a central dictation system wherein dictated messages are recorded on tape T from individual ones of plural remote stations or, alternatively, the di.ctation device may ~e o~ the aonventional so-aalled "desk-top" or indivi:dual type.
ReEerxing now in greater detail to F~GURE l, cassette 12 houses supply and take-up reels and has apertures 1~ and 16 that are adapted to receive drive spindles as well as apertur~ 15 tha~ is adapted to rece.~ve a capstan t all included in a kransport meahani.sm to drive the respective supply and take-up reels. O.ne example o~ such a transport mechanism is shown as having supply reel drive spindle 18 inserted inko aperture 14 of cassette 12 and kake- ;
up reel drive spindle l9 inserted into cassette aperture 16 Cthe " .`
30 ~apstan is not shown~. Take-up reel drive spi.ndle l~ is secured ~:~
ta a drive member 21 which, in turn, is drivingly coupled by a - . . ~. . . :. . : , , :
9~L7 ~ ~
belt 23 to a pulley 25, the latter ~eing dri~en by a motor 27.
In the illustrated arrangemen~, motor 27 is adapted to drive spindle 19 such that tape T is driven in a forward direction.
Rewinding of tape T is effected by driving spindle 18 in an opposite direction by suitable apparatus ~not shown~. In one embodiment thereof, the tape transport mechanism is of the type disclosed in detail in co-pending application Serial No. 768,70~1, filed April 20, 1976, now United States Patent No. 4,061,292 and assigned to the same assignee as ~he instant invention. Hence, the transport mechanism -functions to move tape T in a forward dlrection, as during dictation, playback, or fast-forward~ and ln a reverse direction, as during high-speed rewind.
Supply reel drive spindle 18 is coupled to a reference disc 20 having reference elements 22 periodically spaced along the perimeter of the disc. Spindle 18 may be coupled directly to dlsc 20, as shown, or may be drivingly coupled to the disc by means of intermediate coupling members, such as drive belts, gears, friction rollers, or the like. In either embodiment, disc 20 is adapted to rotate as tape T is transported. More particularly, iE tape T moves in a :Eorward direction, that is, from its suppl~ reel to its take-up reel, disc 20 rotates in a first direction, such as in a counterclockwise direction as viewed in ~IGURB 1. Conversely, if tape T is reversed, disc 20 correspondlngly is reversed so as to rotate in, for example, the clockwise direction.
The Eunction of elements 22 is to represent rotation of dl~sc 20, and thus the movement of tape T. Accordingly, a transducer is provided to sense the passlng o elements 22 past a fixed refer-ence position. In one embodiment, elements 22 comprlse uniformly ~ 7 spaced apertures in disc 20. Accordingly, the transducer used to sense such apertures comprises a light source ~4 and a photo-responsive receptor 26o AS one example thereof, light source 24 is comprised of a light emitti~ng diode, an incandes-cent lamp, or -the like. Similarly, photoresponsive receptor 26 may comprise a phototransistor, a photodiode, or other photoelectrîc devi`ce capable of generating an electrical output signal as a ~unction o~ the light impinging thereon. As another alternative, disc 20 may comprise a slitted 'tchopper" disc, or a disc having thin ele-ments radically extending there~rom. As another em~odiment, ele-ments 22 may comprise light reflective elements and photoresponsive receptor 26 may be disposed in a light reflective path extend:ing ~rom light source 24 to elements 22 and then reflected to the receptor. In all o~ these embodiments, it is appreciated that light emitted from light source 24 is communicated to photo-responsive receptor 26 along an optical path which is periodically interrupted by disc 20 as the disc rotates in synchronism with the movement o~ tape T. Accordingly, the output signal produced ~y photoresponsive receptor 26 is a generally pu]se-shaped signal having a ~irst transition when the light path between source 24 and receptor 26 ~irst is interrupted and a second, opposite transi-tion when that light path is resumed. Stated otherwise, the posi-tive and negative edges o~ the pulse signal are produced at eaah light-to-dark and dark-to-light transition o~ elements 22 in disc 20. It may be appreciated that various other re~erence d~vices can be used to produce a similar pulse signal Thusl elements 22 may comprise uniormly spaced magnetic members and recep~or 26 may be a corresponding detector, such as a Hall effect element. Other magnetic transducing devices can, o~ course, be usedO
3~?8~ 7 The output of receptor 26 is ~upplied through an amplifier 28 to a pulse generator 30. In one embodiment thereof, amplifier 28 may comprise a hysteresis amplifier adapted to sup-ply pulse generator 30 with uniform pulses that are substantially unaEfected by variations in the light-sensing characteristics of receptor 26 or the light-emitting characteristics of source 24 due to the agi~g of these elements, environmental conditions, or other external ~actors. Pulse generator 30 is adapted to produce a narrow pulse, such as an impuse, of predetermined polarity at each transi-tion in the reference pulses applied thereto by amplifier 28 fromreceptor 26. As will soon be described, these impulses produced by pulse generator 30 are adapted to be selectively counted in a pulse counter 52. Accordingly, the output of pulse generator 30 ls coupled to counter 52 via a steering circuit ~ormed of coinci-dence gates, such as AND gates 40 and 42, respectively.
Counter 52 is a bi-directional, or UP/DOWN counter adapted to increment its count in response to pulses applied to an UP input terminal 54 and, conversely~ to decrement its count in response to pulses applied to a DOWN input terminal 56. As illustrated, AND gates 40 and 42 apply the pulses generated by pulse generator 30 selectively to UP input terminal 54 and to DOWN input terminal 56 of counter 52, depending upon the direa-tion in which tape T is moved in cassette 12 by the tape transpor-t mechanism. For example, when tape T is reversed, pulses are applied to UOWN input terminal 56, whereby counter 52 counts down to decre-men~ its count. Likewi~s, when tape T is driven in the Eorward direction, pulses are applied to UP input termi~l 54, whereby counter 52 counts up to increment its count.
The apparatus used to selectively control ~ND ~ates 40 and 42 ~or this pulse steering Eunction now will be described.
-8~
~8~9~L~
~hen the tape transport mechanism is actuated to d~ive tape T
forward, a corresponding ~D signal is produced. Also, when tape T is reversed, a REW signal is produced. These FWD and REW
signals are produced by conventional devices (not shown), such as control switches, selector logic, and the like. The specific apparatus used to produce these FWD and REW signals forms no part of the present invention per se. It merely ma~ be assumed that these signals are mutually exclusive so that when the FWD signal is produced the REW signal is not present andl conversely, when the REW signal is produced the FWD signal is not present. It will be assumed further that each of these FWD and RF~ signals is a positive potential and may be represented, in binarv nota~
~ion, as a binary "1". The FWD signal is adapted to be supplied to an input terminal 44 which, in turn, is coupled to one input o~ an AND gate 34. The REW signal is adapted to be applied to an input terminal 46 which is coupled to an input terminal of an AND gate 36.
As mentioned above, and as will be described in greater detail below, pulse generator 30 is adàpted to produae impulses of predetermined polarity in response to transitions in the pulses applied thereto by amplifier 28. It will be assumed that such im- i pulses are of pos~tive polarity. Hence, the output signal supplied by pulse generator 30 normally is at a relatively low level excep-~~or the positive impulses. It will be recognized by those oE orcl:i-nary skill in the art that such a relatively low voltage potential corresponds to a binary "0". The train of impulses is inverted by a logic inverter 32 and then supplied to another input o~ each AND
gate 34 and 36. Accordingly, inverter 32 applies a signal that normally is a binary "1", except for periodic impulses, to AND
gates 34 and 36. The output of AND gate 34 is connected to the .
'7 set input terminal o~ a bistable multi;vibrator, such as a flip-flip circuit 38, and the output o~ AMD gate 36 is connected to the reset input terminal of this flip-flop circuit. Thus, ~lip flop circuit 38 will be set to its 1 state when the FWD signal coincides with the binary "1" produced by inverter 32, and the ~lip-flop circuit will be reset to its 0 state when the RFW signal coincides with the binary "1" produced by inverter circuit 32.
As shown, the 1 output terminal o~ flip-~lop circuit 38 is con-nected to another input of AND gate 40 and the 0 output terminal of ~lip-flop circuit 38 i5 connected to another input of AND gate 38, one or the other o~ AND gates 40 and 42 ~s conditloned to suppl~ the impulses produced by pulse generator 3a to UP input terminal 54 or ~OWN input terminal 56, respectivelyl of counter 52.
As will soon become apparent, the use of AND gates 34, 36, 40 and 42 and flip-flop circuit 38 prevents counter 52 ~rom reversing its counting direction in the middle o~ an impulse.
Counter circuit 52 includes at least one ou~put terminal 58. The counter circuit is o~ the type that provides a binary "1"
at its output terminal 58 when its count is equal to an initial, or preset, value, and this binary "1" changes to a binary ~a~
when its count is, for example, decremented from that initial count. If desired, these binary notations may be reversed. Out- `
put terminal 58 is connected through an OR cirauit 64 -to the se-t input terminal o~ a Elip-flop circuit 66. The reset lnput terminal Elip-Elop circuit 66 is connected to AND gate 42. Hence, depend-ing upon the count in counter circuit 52, ~lip-:~lop circuit 66 either is ~et to its 1 state or is rese-t to its 0 state. The 0 output terminal of ~lip-flop circuit 66 is connected through a diode 67 and an inverter 68 to an output terminal 7~. A capacitor 7~ is connected between the inverter input and ground so as to be g~
charged when the flip-flop circuit is reset. When flip-flop circuit 66 subsequently is set, capacitor 70 provides a predeter-mined delay before a corresponding output signal is provided at output terminal 74 by inverter 68, this output signal being indica-tive of the fact that tape T has reached its farthest advance posi-tion. This farthest advance signal, which corresponds to a binary "1", is fed back to one input of an AND gate 72 to apply a preset signal to control input terminal 62 of counter circuit 52. The output of AND gate 72 also is applied through OR circuit 64 to the set input terminal of flip-flop circuit 66. As shown, the other input of AND gate 72 is adapted to be supplied with the FWD
signal.
The manner in which farthest advance apparatus 10 operates to produce the farthest advance output signal at output texminal 74 now will be described. Let it be assumed that tape T
is driven in the forward direction, as during a dictate operation, and that the farthest advance signal is provided at output terminal 74. Accordingly, the FWD signal is applied to terminal 44 and is gated in AND gate 72 with the farthest advance signal to preset ~0 counter circuit 52. Consequently, even though disc 20 rotates in synchronism with the forward movement of tape T, the resultant im-pulses produced by pulse generator 30 and applied to UP input ker-minal 54 o~ counter circuit 52 are not effective to .~ncrement the c~unt of -this counter circuit because oE the presenc~ oE the preset lnput.
IE an operator now wishes to review a portion oE his pr~viously dictated message, suitable controls (not shown) are operated and tape T is reversed. Accordingly, the F~D signal !' ` .
applied to terminal 44 terminates and the REW si`gnal now i.s applied to terminal 46. Hence, AND gate 36 is conditioned to reset flip-flop circuit 38 to its 0 state when inverter 32 applies a binary "1" to AND gate 36. This resetting of flip-flop circuit 38 applies a binary "1" to AND gate 42 to condition this AND gate to supply the impulses produced by pulse generator 30 to DOWN input terminal 56 of counter 52. Since the FWD signal has terminated, AND gate 72 no longer appli~es ~he preset signal to counter circuit 52 and the count of this counter circuit is decremented in response to each impulse applied thereto as disc 20 rotates. It should be appreciated that, regardless oE the .:. ..
direction of rotation of disc 20, amplifier 28 applies a substan-tially rectangular pulse signal to pulse generato~ 30.
The count exhibited by counter circuit 52 is decremented ~elow its initial, or preset~ count in response to the first impulse applied to DowN input terminal 56. Hence, a binary "0" is provided at output terminal 58. Concurrently, the impulse applied by AND
gate 42 to DOWN input terminal 56 also i`s applied to the reset input terminal of flip-flop circuit 66. Therefore, Elip-flop cir- : ;
cuit 66 is reset to charge capacitor 70 to the level O:e a hinary "1"
which is inverted by inverter 68 to terminate the ~arthest advance 20 signal heretoEorm provided at output terminal 74. `"
Let it now be assumed that, after rewinding the desired amount of tape T, the operator plays ~ack the rewound tape so as r to review his dictated message. Tape T now is driven forwa:rd, and d.isc 20 rotates accordingly. Also, a~ter suitabl~ dela~s prov~d~cl by capacitors 50 and 48, the REW signal at terminal 46 is termLnat~d and the FWD signal again is applied to termïnal 44. These delays, wh.iah preEerably are in the REW ancl FWD signal generators tnot shown) allow the motion due to inertia to termi~nate. Thence, AND gate 36 now is de-energized and AND gate 34 i5 conditioned by the FWD signal such that when inverter 32 applies a binary "1" thereto, flip-flop circuit 38 is set. Hence, the impulses produced by pulse generator 9~7 30 in response to each transition in the pulses applied b~ ampli-fier 28 as disc 20 rotates, ara transmitted through now-conditioned AND gate 40 to uP input terminal 54 of counter 52. It is recognized that, when flip-~lop circuit 38 is set, AND gate 42 no longer is conditioned to transmit impulses. Consequently, counter circuit 52 counts each impulse to increment its count toward its initial, pre-se-t count. Thus, depending upon ~he direction in wh~ch tape T is moved, counter circuit 52 either counts;up or counts down in re-sponse to each impulse produced by pulse generator 30.
When tape T reaches its farthest position previously attained, that is, its farthest advance position, the total number of impulses counted up by counter circuit 52 will be equal to the total number of impulses which previously had been counted down.
Conse~uently, counter circuit 52 will be restored to its initial, or present, count. There~ore, a binary "1" is provided at counter output terminal 58 to set flip-flop circuit 66 to its 1 state.
Consequently, capacitor 70 no longer is suppli.ed with charging current, and thus discharges. After a predetermined delay ~de.ter-mined by the discharge time constant~, the voltage across the capacitor discharges to a`binary "0" level which, ater being inv~rted by inverter 68, is the farthest signal. IE desired, and in accordance with an alternative embodiment, aapacitor 70 may be omitted. The farthest advance si~nal thus produced also is applied kh~ough AND gate 72 to preset counter circuit 52 and, additionally, through OR circuit 64 t.o insure that flip-Elop circuit 66 is main-tained in its 1 state. However, if des.ired, this additional latter ~una-tion oE the ~arthest advan4e si~nal may be omitted.
4~
It should be noted that counter circuit 52 wi11 increment its coun-t in response to impulses produced by pulse generator 30 if tape T is advanced at a relatively slow speed, as during playback or at a higher speed, as during ~ast-forward movement. In both modes o~ transporting tape T/ the FWD signal is applied to terminal 44.
One of ordinary skill i.n the art will appreciate that the farthest advance signal produced at output terminal 74 can be used for various purposes. For examplel in the event that communication between a dictate station and the recording station, as in a central dictation system, is termi`nated after an operator has reviewed only a portion of his previously dictated message, it is desired to return tape T to its farthest advance position prior to the time that the recording unit is made available for a subsequent dictating operation. Accordingly, the absence o~ a ~arthest advance signal at output terminal 74 is used to transport tape T at, for example, a fast-forward speed, when a di`sconnection between the dictate station and the recording station i`s sensed.
When tape T reaches its farthest advance position to produce the ~arthest advance signal at output terminal 74, ~urther movement o the tape is terminated and, moreover, the record~ng unit is made available ~or a subsequent connection to a dictate station.
It is appreciated that, when tape T is driven at the fast-~orward ~peed~ the tape may continue to coast for a relatively short dis-kance even a~ter the transport mechan~sm is de-energi~ed. This may be used to assure that a su~sequent dictate opera-tion will be su~iciently spaced from the previously recorded message.
1~ , Another use of the farthest advance signal provided at output terminal 74 is to permit an operator to advance tape T
to its farthest advance position aft~r reviewing a port~on of a dictated message without listeniny to or concentrating on the remainder of that message. Thus, during a pla~back mode, tape T
continues to advance until its farthest advance position is re-stored, whereupon the farthest advance signal is produced and the tape transport mechanism is de-energized to aw~ait ~urther dictation by the operator~ In this operation, capacitor 70 is advantageous in that it provides a brief delay between the time that tape ~ reaches its farthest advance position and the time that the farthest advance signal is produced to de-energize the tape transport mechanism. This delay insures that the operator can resume dictation without obliterating any of his previously recorded message. Similarly, iE after reviewing a portion oE
his dictated message, the operator initiates a East-forward tape movement, tape T is driven at the fast-forward speed until the tape returns to its farthest advance position, whereupon the ~arthest advance signal is produced to de-energize the tape transport mechanism.
Some alternative embodiments to the Earthest advance apparatus lO are contemplated. For example, the FWD and REW
si~nals can be applied directl~ to AND gates 4n and 42, and AND gates 34 and 36 and flip-Elop circuit 38 may be omitted.
However, in the absence oE AND gates 34 and 36 and flip-Elop circuik 38, there is the possi`bility that, ~or example, the FWD signal is produced beore disc 20 has completely stopped.
This means that the FWD signal can be produced simultaneously wi~h an impulse, whereby counter circuit 52 would be improperly incre-mented. However, by providing AND gates 34 and 36~ the concurrent .
application of a FWD signal and an impulse tol for example, AND
gate 34 will not be effective to change the state of ~lip-flop circuit 38. Thus, counter circuit 52 cannot be improperly incre-mented (or decremented~ by reason o~ the concurrence of either the FWD signal or the REW signal and an impulse. Also, flïp-flop cir-cuit 38 insures that counter circuit 52 is incremented (or decre-mented) by an impulse produced when disc 20 coasts (as by inertia) even though the FWD (or REW~ signal has terminated, thus preventing a "missed" impulse.
In the embodiment described above, it is assumed that ;
counter circuit 52 is preset to an initial count from which the counter circuit i8 decremented when tape T is reversed. Thus, ~ -during a subsequent ~orward motion of tape T, counter circuit 52 will be restored to its preset count once tape T has reached its farthes-t advance position. In an alternative embodiment, counter 52 need not be preset to an initial count. Rather, ~ach impulse produced by pulse generator 3Q during forward movement o~ tape T
can be used to increment the counter circuit even a~ter the tape has reached its farthest advance position. When tape T is reversed, ~0 the highest count attained by the counter circuit is gated into a sultable storage device just prior to tape reversal. Then, the actual count o~ the counter circuit is compared to the hi~h~s-tl:
count stored in the storage deviae. O~ course, as t~pe ~ continues to ha rewound, the count stored in the storage device will not com-pare to -the count actually exhibited by the counter circuit. Also, a9 the dlrection o~ tape T is reversed and the counter circuit is incremented~ its actual count still will not compare with the stored count until the tape arrives at its ~arthest position. At that time, a comparison is obtained beween the stored count and the actual count, this comparison being used to produce the farthest advance signal.
It may be recogni~ed tha t as the amount of tape on the supply reel is changed, the diameter thereof likewise changes and the rotary speed of disc 20 will increase (decrease during rewind tape movement). However, this has no effect upon the operatIon of the illustrated embodiment because, in returning to the farthest advance position, the same length of tape is moved forward as was moved backward. Hence, the same number of apertures 22 are counted~
This e~fectively cancels any change in the rotary speed of disc 20.
One embodiment of pulse generator 30 now will be described with reference to the schematic diagram shown in FIGURE 2. The pulse generator is formed of complementary transistors 102 and 114.
A voltage divider circuit including resistors 104 and 106 is pro-vided between a source of operating potential ~V and a re~erence potential, such as ground. The output of this voltage divider circuit is connected to the emitter of transistor 102 to apply a predetermined bias voltage thereto. The collector of transistor 102 is connected through a resistor 108 and a rectiier 110 to the base of transistor 114. The emitter of transistor 114 is connected directly to the source +V and its base is connected to the source through a bias resistor 112. As shown, the collector o~ kransistor 114 is connected to ground through a load ~esistor 116, the output of pulse generator 30 being derived from the collector o transistor 114.
In operation, th~ base oE transistor 102 ls connected to ampll~ier 28 so as to receive the pulses produced in response to the rotation o~ reerence disc 20 as tape T moves. As exagge-rated in FIGURE 2, the leading and trailing edges of these pulses are not absolutely perpendicular and, therefore, exhLbit some degrèe of slope. When the leading edge of this pulse exceeds the bias voltage at the emitter of transistor 102 (plus the base-emitter voltage), transistor 102 is turned on and is driven toward saturation. Consequently, the collector voltage, which pre-viously had been equal to ~he source voltage ~v, applied through resistor 112, rectifier 110 and resistor 108, rapidly decreases to approximately the emitter bias voltage of transistor 102.
One of ordlnary skill in the art will appreciate that the base-collector junction of a transistor may be considered as including a diode poled to be reverse biased when the collector voltage exceeds the base voltage. However, as the leading edge of the pulse signal applied to transistor 102 continues to increase, this diode becomes forward biased. Hence, the voltage at the collector of transistor 102, which had been reduced to a lower level, now is driven in the positive direction by the inCreaSincJ
voltage applied to the base of this transistor. Therefore, the collector voltage of transistor 102 normally exhibits a higher voltage level, except during brief intervals that coincide with a portion o~ the rise time, or leading edge, of the pulsès ap-plied to the transistor.
A similar phenomenon occurs at the trailing edge of the pulse applied by amplifier 28. Thus, as this trailing edge decrea~es, transistor 102 is driven out o~ saturation and its base-collector diode becomes reverse biased. Accordingly, the collector voltage of transistor 102 i5 reduced ~o.r a brie:E inter-val, or until its base voltage no longer exceeds the bias voltage applied to its emitter (plus the base-emitter voltage). At that ::
tlme, transistor 102 is turned off. Hence, it is appreciated that the collector voltage of transistor la2 appears as a series oE negative-going impulses corresponding to the leading and trail-ing edges of the pulse signal applied thereto by amplifier 28.
These negative-going impulses are inverted by transistor 114 and then supplied to the remaining circuity illustrated in FIGURE 1.
While the present invention has been particularly shown in conjunction with a preferred embodiment thereof, it should be apparent that various modifications in form and details can be made without departing from the spirit and scope of the invention.
Some of these modifications and alternative embodiments have been described hereinabove. As another modification, counter 52 may be of the type having a second output terminal whereat a signal, such as a binary "1", is provided when the count exhibited by coun~r 52 changes from its initial count. This signal, rather ~han the signal produced by AMD gate 42, can be used to reset 1ip-flop circuit 66.
In addition, it should be recognized that, although this farthest advance apparatus can be used advantageously with a bi-directionally movable web, such as a tape housed in a cassette, or driven ~rom one reel to another, or forming an endless tape loop, the apparatus also can be used to .indicate
This invention relates to apparatus for indicating the farthest advance position of a bi~directionally movable medium and, more particularly, to solid-state electronic farthest advance apparatus which can be used, for example, in conjunction with a reversible web without requiring a direct sensing of the condition of the web.
In many processing systems, such as a web processing system, i-t often is necessary to bi-directionally move the web relative to a processing station. If the web is moved normally in a forward direction, it is desirable, once the web is reversed, to indica-te when the web has been returned to its previous ~arthest advanca position.
One type oE web processing system wherein knowledge of the ~arthest advance position of the web is desirable is a dictat-ing ~ys tem. As one example, in a central dictation system, a central recording unit is adapted to be connected to individual ones of plural remote dictate stations. Once this connection is obtained, an operator at the remote station can dictate messages ~0 on-~o the recording medium at the central recording station and c~n control various functions, such as dictatel rewind, playback, and the like. In many applications using this central system, a :
~ubsequent operator at another remote station can dictate messages on~o ~he recording medium ~ollowing the completion o:E the d:lctation ~p~ration by the previous operator. It has been found that, in ~me in9tances, the last action taken by the previous operator pri4~ to disconnecting his remote station from the central record-ing station is to partially review his dictated message. Hence, at the time of disconnection, the record medium has not been fully restored to the ~arthest advance position corresponding to the end -. .
~, .
~ g~of the dictated message. Therefo~e, to prevent the su~sequent operator from dictating his message over the remaining porti~n of the previously dlctated message, it is necessary to return the medium to its farthest advance position prior to effecting a connection between t~e remote station of the subse~uent operator and the central recording station.
In a central dictation system of the type disclosed in U. S. Patent No. 3,823,274, assigned to the assi.gnee of the instant invention, the recording medium i~s an endless loop of magneti~c tape :~
capable of being stored in serpentine folds in a housing. A record/~
playback transducer is provided .i`n the hous~ng and the tape is driven bi-directionally past the transducer. During forward move-men-t oE the tape, as in a recording mode, the tape is drawn taut over various guide rollers. However, when the tape is reversed, .
this tautness is relaxed and a loop is formed ~etween a set oE
guide rollers. Consequently, to determine whether the tape has reached its farthest advance position, it merely is necessary to .
sense the tautness of the tape. Thus, when all of the rewound tape has been transporteA in the forward d~rection, as duri`ng the playback of a previously recorded message, the tape once again is taut. As diclosed in U. S Patent No. 3,823,27~, the tau-tness of the tape i9 sensed by a mechanical switch that is closed when ~h~ t~p:e i9 rewound to ~orm the loop and that is opened when the ~ape is -taut, thereby indicatlng that the tape has been restored tQ its ~arthest advance positi~on.
~ 1-though th.is technique of using a mechanical swi.tch to detect the tape tautness as an indi.cation oE the farthest advance position is sati.sfactory for a central system provi.ded with an endless loop of tape, it is not completely successful when used with other recording media. For example, lf the recording - .. -.
medium is a magnetic tape housed in a casset~e, reversal of the tape from its farthest advance position does not result in the formation of a tape loop as described above. Although the amount of tape payed out from the cassette supply reel onto the take-up reel can be sensed by measuring the diameter of the take-up reel and then sensing when this diameter is reduced, as during rewind, and subsequently restored to indi-cate that the tape has returned to its Earthest advance position, such reel-measuring is highly inaccurate.
As another example, if the recording medium is a belt that is scanned by a traversing record/playback head, a review operation is performed by movin~ the head baàkward relative to tho belt. ~ence, Earthest advance cannot be detected by sensing the tautness or slackness of the medium as d~sclosed in the afore-noted patent.
OBJECTS OF T~E INVENTION
Therefore, it is an object of the present invention to provide improved apparakus for indicating the farthest advance position of a bi-directionally movable medium.
~0 Another object o~ this invention is to provi~de Earthest advance indicating apparatus which can be used in a record~ng system and which need not rely upon the format.ion of a loop in ~he recording medium.
A ~urther object of this invention is -to provide farthest advanGe indicating apparatus ~or use in a d.ictation system oE the type using a web o~ recordln~ medium.
An additional object oE th~s invention is to provide ~arthest advance indicating apparatus where~n solid-state elec-tronics are used to indicate when a recording tape is reversed from its farthest advance position and when that tape has been restored to its farthest advance position.
.''~', ' ' ' ~L8~5~94~
Yet another object of this invention is to provide apparatus for use in a dictation system employing a magnetic tape cassette wherein the farthest advance position of the tape is indicated.
Various other objects, advantages and features o~ this invention will become readily apparent from the ensuing detailed discussion, and the ``
novel features will be particularly pointed out in the appended claims.
SUMMARY O~ THE INVENTION
Apparatus for indicating the farthest advance position of a medium bi-directionally movable by a transport mechanism is provided with a pulse 1~ generator operable as a function of the movement of the medium to generate pulses as the medium moves either in a first or second direction, a counter eouplecl to the pulsc~ generator and responsive to each pulse so as to in-el~em~ntally change its count from an initial count, for example, to reduce its count, when the medium moves in the second direction and then to increase ~
its count in response to each pulse when the medium reverses direction so ~ `
as to move in the first direction, and an output device coupled to the counter and responsive to the restoration of the counter's initial count to produee a farthest advance signal indicating that the medium llas returned to its ~arthest advance position.
Accorcling to a broad aspeet of the present invention, there is provi~lecl apparatus for indicating the farthest advanee position oE a meclium ~i-directionally movable by a transport meehanism, eomprising: means Eor pr~vi~lng a first signal when said transport meehanism is aetuated to move ~aicl medillm in a ~irst direction; means for providing a seeond signal when s~id transport meehanism is aetuatecl to move said medium in a second direction opposi~o to said ~lrst direetion; pulse generating means operable with said tr~nsport mechanism to generate pulses representing the amount that said medium moves either in said first or in said seeond direetion; bi-directional counting means seleetively responsive to each generated pulse to ineremental-ly change the count thereof in a first or second direction; gating means forcoupling said generated pulses to said counting means when said medium moves in said second direction so that said counting means incrementally changes its .:
~ ' :
~.~8~9~7 count from an initial count and in a first direction and for coupling said ~.
generated pulses to said counting means when said medium moves in said first direction following movement in said second direction so that said counting means incrementally changes its count in a second direction so as to be restored to said initial count; gate control means responsive to said first and second signals and to said generated pulses for energizing said gating means when said first or second signal is initiated in non-coincidence with a generated pulse and for maintaining said gating means energized if said first or second signal terminates but said pulses continue to be generated; .
and output means for producing a farthest advance signal when said counting means is restored to said initial count and for maintaining said farthest advance signal unt~l said medium subsequently is moved in said second direc-tion.
BRIEF DESCRIPTION OF`THF. DRAWINGS
The following detailed description, given by way of example, will best be understood in conjunction with the accompanying drawings wherein:
FIGURE 1 is a logic diagram of the farthest advance apparat~ls in accordance with the present invention; and -~a- :
: .
FIGURE 2 is a schematic diagram of a circuit used in the farthest advance apparatus shown in FIGUR~ 1.
DETAILED DESCRIPTION OF A ~REFERRED EMBODIMENT
Although the present invention can be used to indicate when virtually any bi-directionally movable device is moved awav from the farthest position it last occupied and then is restored to that ~arthest position, the following description relates to the use of this invention with a bi-directionally movable web.
Fur~hermore, as will now be described with reference to FIGURE l, ~:
this web here is a magnetic recordi.n~ tape T bi-direationally driven between, for example, a supply reel and a kake-up reel.
To best illustrate the novel aspects o~ farthest advance indi-cating apparatus lO, it will ~e assumed that tape T is housed in a cassette 12 and is used in a recording/playback device, ~uch as a dictation device. Although not necessary to a full understanding of this invention, the dictation devi`ce may be included in a central dictation system wherein dictated messages are recorded on tape T from individual ones of plural remote stations or, alternatively, the di.ctation device may ~e o~ the aonventional so-aalled "desk-top" or indivi:dual type.
ReEerxing now in greater detail to F~GURE l, cassette 12 houses supply and take-up reels and has apertures 1~ and 16 that are adapted to receive drive spindles as well as apertur~ 15 tha~ is adapted to rece.~ve a capstan t all included in a kransport meahani.sm to drive the respective supply and take-up reels. O.ne example o~ such a transport mechanism is shown as having supply reel drive spindle 18 inserted inko aperture 14 of cassette 12 and kake- ;
up reel drive spindle l9 inserted into cassette aperture 16 Cthe " .`
30 ~apstan is not shown~. Take-up reel drive spi.ndle l~ is secured ~:~
ta a drive member 21 which, in turn, is drivingly coupled by a - . . ~. . . :. . : , , :
9~L7 ~ ~
belt 23 to a pulley 25, the latter ~eing dri~en by a motor 27.
In the illustrated arrangemen~, motor 27 is adapted to drive spindle 19 such that tape T is driven in a forward direction.
Rewinding of tape T is effected by driving spindle 18 in an opposite direction by suitable apparatus ~not shown~. In one embodiment thereof, the tape transport mechanism is of the type disclosed in detail in co-pending application Serial No. 768,70~1, filed April 20, 1976, now United States Patent No. 4,061,292 and assigned to the same assignee as ~he instant invention. Hence, the transport mechanism -functions to move tape T in a forward dlrection, as during dictation, playback, or fast-forward~ and ln a reverse direction, as during high-speed rewind.
Supply reel drive spindle 18 is coupled to a reference disc 20 having reference elements 22 periodically spaced along the perimeter of the disc. Spindle 18 may be coupled directly to dlsc 20, as shown, or may be drivingly coupled to the disc by means of intermediate coupling members, such as drive belts, gears, friction rollers, or the like. In either embodiment, disc 20 is adapted to rotate as tape T is transported. More particularly, iE tape T moves in a :Eorward direction, that is, from its suppl~ reel to its take-up reel, disc 20 rotates in a first direction, such as in a counterclockwise direction as viewed in ~IGURB 1. Conversely, if tape T is reversed, disc 20 correspondlngly is reversed so as to rotate in, for example, the clockwise direction.
The Eunction of elements 22 is to represent rotation of dl~sc 20, and thus the movement of tape T. Accordingly, a transducer is provided to sense the passlng o elements 22 past a fixed refer-ence position. In one embodiment, elements 22 comprlse uniformly ~ 7 spaced apertures in disc 20. Accordingly, the transducer used to sense such apertures comprises a light source ~4 and a photo-responsive receptor 26o AS one example thereof, light source 24 is comprised of a light emitti~ng diode, an incandes-cent lamp, or -the like. Similarly, photoresponsive receptor 26 may comprise a phototransistor, a photodiode, or other photoelectrîc devi`ce capable of generating an electrical output signal as a ~unction o~ the light impinging thereon. As another alternative, disc 20 may comprise a slitted 'tchopper" disc, or a disc having thin ele-ments radically extending there~rom. As another em~odiment, ele-ments 22 may comprise light reflective elements and photoresponsive receptor 26 may be disposed in a light reflective path extend:ing ~rom light source 24 to elements 22 and then reflected to the receptor. In all o~ these embodiments, it is appreciated that light emitted from light source 24 is communicated to photo-responsive receptor 26 along an optical path which is periodically interrupted by disc 20 as the disc rotates in synchronism with the movement o~ tape T. Accordingly, the output signal produced ~y photoresponsive receptor 26 is a generally pu]se-shaped signal having a ~irst transition when the light path between source 24 and receptor 26 ~irst is interrupted and a second, opposite transi-tion when that light path is resumed. Stated otherwise, the posi-tive and negative edges o~ the pulse signal are produced at eaah light-to-dark and dark-to-light transition o~ elements 22 in disc 20. It may be appreciated that various other re~erence d~vices can be used to produce a similar pulse signal Thusl elements 22 may comprise uniormly spaced magnetic members and recep~or 26 may be a corresponding detector, such as a Hall effect element. Other magnetic transducing devices can, o~ course, be usedO
3~?8~ 7 The output of receptor 26 is ~upplied through an amplifier 28 to a pulse generator 30. In one embodiment thereof, amplifier 28 may comprise a hysteresis amplifier adapted to sup-ply pulse generator 30 with uniform pulses that are substantially unaEfected by variations in the light-sensing characteristics of receptor 26 or the light-emitting characteristics of source 24 due to the agi~g of these elements, environmental conditions, or other external ~actors. Pulse generator 30 is adapted to produce a narrow pulse, such as an impuse, of predetermined polarity at each transi-tion in the reference pulses applied thereto by amplifier 28 fromreceptor 26. As will soon be described, these impulses produced by pulse generator 30 are adapted to be selectively counted in a pulse counter 52. Accordingly, the output of pulse generator 30 ls coupled to counter 52 via a steering circuit ~ormed of coinci-dence gates, such as AND gates 40 and 42, respectively.
Counter 52 is a bi-directional, or UP/DOWN counter adapted to increment its count in response to pulses applied to an UP input terminal 54 and, conversely~ to decrement its count in response to pulses applied to a DOWN input terminal 56. As illustrated, AND gates 40 and 42 apply the pulses generated by pulse generator 30 selectively to UP input terminal 54 and to DOWN input terminal 56 of counter 52, depending upon the direa-tion in which tape T is moved in cassette 12 by the tape transpor-t mechanism. For example, when tape T is reversed, pulses are applied to UOWN input terminal 56, whereby counter 52 counts down to decre-men~ its count. Likewi~s, when tape T is driven in the Eorward direction, pulses are applied to UP input termi~l 54, whereby counter 52 counts up to increment its count.
The apparatus used to selectively control ~ND ~ates 40 and 42 ~or this pulse steering Eunction now will be described.
-8~
~8~9~L~
~hen the tape transport mechanism is actuated to d~ive tape T
forward, a corresponding ~D signal is produced. Also, when tape T is reversed, a REW signal is produced. These FWD and REW
signals are produced by conventional devices (not shown), such as control switches, selector logic, and the like. The specific apparatus used to produce these FWD and REW signals forms no part of the present invention per se. It merely ma~ be assumed that these signals are mutually exclusive so that when the FWD signal is produced the REW signal is not present andl conversely, when the REW signal is produced the FWD signal is not present. It will be assumed further that each of these FWD and RF~ signals is a positive potential and may be represented, in binarv nota~
~ion, as a binary "1". The FWD signal is adapted to be supplied to an input terminal 44 which, in turn, is coupled to one input o~ an AND gate 34. The REW signal is adapted to be applied to an input terminal 46 which is coupled to an input terminal of an AND gate 36.
As mentioned above, and as will be described in greater detail below, pulse generator 30 is adàpted to produae impulses of predetermined polarity in response to transitions in the pulses applied thereto by amplifier 28. It will be assumed that such im- i pulses are of pos~tive polarity. Hence, the output signal supplied by pulse generator 30 normally is at a relatively low level excep-~~or the positive impulses. It will be recognized by those oE orcl:i-nary skill in the art that such a relatively low voltage potential corresponds to a binary "0". The train of impulses is inverted by a logic inverter 32 and then supplied to another input o~ each AND
gate 34 and 36. Accordingly, inverter 32 applies a signal that normally is a binary "1", except for periodic impulses, to AND
gates 34 and 36. The output of AND gate 34 is connected to the .
'7 set input terminal o~ a bistable multi;vibrator, such as a flip-flip circuit 38, and the output o~ AMD gate 36 is connected to the reset input terminal of this flip-flop circuit. Thus, ~lip flop circuit 38 will be set to its 1 state when the FWD signal coincides with the binary "1" produced by inverter 32, and the ~lip-flop circuit will be reset to its 0 state when the RFW signal coincides with the binary "1" produced by inverter circuit 32.
As shown, the 1 output terminal o~ flip-~lop circuit 38 is con-nected to another input of AND gate 40 and the 0 output terminal of ~lip-flop circuit 38 i5 connected to another input of AND gate 38, one or the other o~ AND gates 40 and 42 ~s conditloned to suppl~ the impulses produced by pulse generator 3a to UP input terminal 54 or ~OWN input terminal 56, respectivelyl of counter 52.
As will soon become apparent, the use of AND gates 34, 36, 40 and 42 and flip-flop circuit 38 prevents counter 52 ~rom reversing its counting direction in the middle o~ an impulse.
Counter circuit 52 includes at least one ou~put terminal 58. The counter circuit is o~ the type that provides a binary "1"
at its output terminal 58 when its count is equal to an initial, or preset, value, and this binary "1" changes to a binary ~a~
when its count is, for example, decremented from that initial count. If desired, these binary notations may be reversed. Out- `
put terminal 58 is connected through an OR cirauit 64 -to the se-t input terminal o~ a Elip-flop circuit 66. The reset lnput terminal Elip-Elop circuit 66 is connected to AND gate 42. Hence, depend-ing upon the count in counter circuit 52, ~lip-:~lop circuit 66 either is ~et to its 1 state or is rese-t to its 0 state. The 0 output terminal of ~lip-flop circuit 66 is connected through a diode 67 and an inverter 68 to an output terminal 7~. A capacitor 7~ is connected between the inverter input and ground so as to be g~
charged when the flip-flop circuit is reset. When flip-flop circuit 66 subsequently is set, capacitor 70 provides a predeter-mined delay before a corresponding output signal is provided at output terminal 74 by inverter 68, this output signal being indica-tive of the fact that tape T has reached its farthest advance posi-tion. This farthest advance signal, which corresponds to a binary "1", is fed back to one input of an AND gate 72 to apply a preset signal to control input terminal 62 of counter circuit 52. The output of AND gate 72 also is applied through OR circuit 64 to the set input terminal of flip-flop circuit 66. As shown, the other input of AND gate 72 is adapted to be supplied with the FWD
signal.
The manner in which farthest advance apparatus 10 operates to produce the farthest advance output signal at output texminal 74 now will be described. Let it be assumed that tape T
is driven in the forward direction, as during a dictate operation, and that the farthest advance signal is provided at output terminal 74. Accordingly, the FWD signal is applied to terminal 44 and is gated in AND gate 72 with the farthest advance signal to preset ~0 counter circuit 52. Consequently, even though disc 20 rotates in synchronism with the forward movement of tape T, the resultant im-pulses produced by pulse generator 30 and applied to UP input ker-minal 54 o~ counter circuit 52 are not effective to .~ncrement the c~unt of -this counter circuit because oE the presenc~ oE the preset lnput.
IE an operator now wishes to review a portion oE his pr~viously dictated message, suitable controls (not shown) are operated and tape T is reversed. Accordingly, the F~D signal !' ` .
applied to terminal 44 terminates and the REW si`gnal now i.s applied to terminal 46. Hence, AND gate 36 is conditioned to reset flip-flop circuit 38 to its 0 state when inverter 32 applies a binary "1" to AND gate 36. This resetting of flip-flop circuit 38 applies a binary "1" to AND gate 42 to condition this AND gate to supply the impulses produced by pulse generator 30 to DOWN input terminal 56 of counter 52. Since the FWD signal has terminated, AND gate 72 no longer appli~es ~he preset signal to counter circuit 52 and the count of this counter circuit is decremented in response to each impulse applied thereto as disc 20 rotates. It should be appreciated that, regardless oE the .:. ..
direction of rotation of disc 20, amplifier 28 applies a substan-tially rectangular pulse signal to pulse generato~ 30.
The count exhibited by counter circuit 52 is decremented ~elow its initial, or preset~ count in response to the first impulse applied to DowN input terminal 56. Hence, a binary "0" is provided at output terminal 58. Concurrently, the impulse applied by AND
gate 42 to DOWN input terminal 56 also i`s applied to the reset input terminal of flip-flop circuit 66. Therefore, Elip-flop cir- : ;
cuit 66 is reset to charge capacitor 70 to the level O:e a hinary "1"
which is inverted by inverter 68 to terminate the ~arthest advance 20 signal heretoEorm provided at output terminal 74. `"
Let it now be assumed that, after rewinding the desired amount of tape T, the operator plays ~ack the rewound tape so as r to review his dictated message. Tape T now is driven forwa:rd, and d.isc 20 rotates accordingly. Also, a~ter suitabl~ dela~s prov~d~cl by capacitors 50 and 48, the REW signal at terminal 46 is termLnat~d and the FWD signal again is applied to termïnal 44. These delays, wh.iah preEerably are in the REW ancl FWD signal generators tnot shown) allow the motion due to inertia to termi~nate. Thence, AND gate 36 now is de-energized and AND gate 34 i5 conditioned by the FWD signal such that when inverter 32 applies a binary "1" thereto, flip-flop circuit 38 is set. Hence, the impulses produced by pulse generator 9~7 30 in response to each transition in the pulses applied b~ ampli-fier 28 as disc 20 rotates, ara transmitted through now-conditioned AND gate 40 to uP input terminal 54 of counter 52. It is recognized that, when flip-~lop circuit 38 is set, AND gate 42 no longer is conditioned to transmit impulses. Consequently, counter circuit 52 counts each impulse to increment its count toward its initial, pre-se-t count. Thus, depending upon ~he direction in wh~ch tape T is moved, counter circuit 52 either counts;up or counts down in re-sponse to each impulse produced by pulse generator 30.
When tape T reaches its farthest position previously attained, that is, its farthest advance position, the total number of impulses counted up by counter circuit 52 will be equal to the total number of impulses which previously had been counted down.
Conse~uently, counter circuit 52 will be restored to its initial, or present, count. There~ore, a binary "1" is provided at counter output terminal 58 to set flip-flop circuit 66 to its 1 state.
Consequently, capacitor 70 no longer is suppli.ed with charging current, and thus discharges. After a predetermined delay ~de.ter-mined by the discharge time constant~, the voltage across the capacitor discharges to a`binary "0" level which, ater being inv~rted by inverter 68, is the farthest signal. IE desired, and in accordance with an alternative embodiment, aapacitor 70 may be omitted. The farthest advance si~nal thus produced also is applied kh~ough AND gate 72 to preset counter circuit 52 and, additionally, through OR circuit 64 t.o insure that flip-Elop circuit 66 is main-tained in its 1 state. However, if des.ired, this additional latter ~una-tion oE the ~arthest advan4e si~nal may be omitted.
4~
It should be noted that counter circuit 52 wi11 increment its coun-t in response to impulses produced by pulse generator 30 if tape T is advanced at a relatively slow speed, as during playback or at a higher speed, as during ~ast-forward movement. In both modes o~ transporting tape T/ the FWD signal is applied to terminal 44.
One of ordinary skill i.n the art will appreciate that the farthest advance signal produced at output terminal 74 can be used for various purposes. For examplel in the event that communication between a dictate station and the recording station, as in a central dictation system, is termi`nated after an operator has reviewed only a portion of his previously dictated message, it is desired to return tape T to its farthest advance position prior to the time that the recording unit is made available for a subsequent dictating operation. Accordingly, the absence o~ a ~arthest advance signal at output terminal 74 is used to transport tape T at, for example, a fast-forward speed, when a di`sconnection between the dictate station and the recording station i`s sensed.
When tape T reaches its farthest advance position to produce the ~arthest advance signal at output terminal 74, ~urther movement o the tape is terminated and, moreover, the record~ng unit is made available ~or a subsequent connection to a dictate station.
It is appreciated that, when tape T is driven at the fast-~orward ~peed~ the tape may continue to coast for a relatively short dis-kance even a~ter the transport mechan~sm is de-energi~ed. This may be used to assure that a su~sequent dictate opera-tion will be su~iciently spaced from the previously recorded message.
1~ , Another use of the farthest advance signal provided at output terminal 74 is to permit an operator to advance tape T
to its farthest advance position aft~r reviewing a port~on of a dictated message without listeniny to or concentrating on the remainder of that message. Thus, during a pla~back mode, tape T
continues to advance until its farthest advance position is re-stored, whereupon the farthest advance signal is produced and the tape transport mechanism is de-energized to aw~ait ~urther dictation by the operator~ In this operation, capacitor 70 is advantageous in that it provides a brief delay between the time that tape ~ reaches its farthest advance position and the time that the farthest advance signal is produced to de-energize the tape transport mechanism. This delay insures that the operator can resume dictation without obliterating any of his previously recorded message. Similarly, iE after reviewing a portion oE
his dictated message, the operator initiates a East-forward tape movement, tape T is driven at the fast-forward speed until the tape returns to its farthest advance position, whereupon the ~arthest advance signal is produced to de-energize the tape transport mechanism.
Some alternative embodiments to the Earthest advance apparatus lO are contemplated. For example, the FWD and REW
si~nals can be applied directl~ to AND gates 4n and 42, and AND gates 34 and 36 and flip-Elop circuit 38 may be omitted.
However, in the absence oE AND gates 34 and 36 and flip-Elop circuik 38, there is the possi`bility that, ~or example, the FWD signal is produced beore disc 20 has completely stopped.
This means that the FWD signal can be produced simultaneously wi~h an impulse, whereby counter circuit 52 would be improperly incre-mented. However, by providing AND gates 34 and 36~ the concurrent .
application of a FWD signal and an impulse tol for example, AND
gate 34 will not be effective to change the state of ~lip-flop circuit 38. Thus, counter circuit 52 cannot be improperly incre-mented (or decremented~ by reason o~ the concurrence of either the FWD signal or the REW signal and an impulse. Also, flïp-flop cir-cuit 38 insures that counter circuit 52 is incremented (or decre-mented) by an impulse produced when disc 20 coasts (as by inertia) even though the FWD (or REW~ signal has terminated, thus preventing a "missed" impulse.
In the embodiment described above, it is assumed that ;
counter circuit 52 is preset to an initial count from which the counter circuit i8 decremented when tape T is reversed. Thus, ~ -during a subsequent ~orward motion of tape T, counter circuit 52 will be restored to its preset count once tape T has reached its farthes-t advance position. In an alternative embodiment, counter 52 need not be preset to an initial count. Rather, ~ach impulse produced by pulse generator 3Q during forward movement o~ tape T
can be used to increment the counter circuit even a~ter the tape has reached its farthest advance position. When tape T is reversed, ~0 the highest count attained by the counter circuit is gated into a sultable storage device just prior to tape reversal. Then, the actual count o~ the counter circuit is compared to the hi~h~s-tl:
count stored in the storage deviae. O~ course, as t~pe ~ continues to ha rewound, the count stored in the storage device will not com-pare to -the count actually exhibited by the counter circuit. Also, a9 the dlrection o~ tape T is reversed and the counter circuit is incremented~ its actual count still will not compare with the stored count until the tape arrives at its ~arthest position. At that time, a comparison is obtained beween the stored count and the actual count, this comparison being used to produce the farthest advance signal.
It may be recogni~ed tha t as the amount of tape on the supply reel is changed, the diameter thereof likewise changes and the rotary speed of disc 20 will increase (decrease during rewind tape movement). However, this has no effect upon the operatIon of the illustrated embodiment because, in returning to the farthest advance position, the same length of tape is moved forward as was moved backward. Hence, the same number of apertures 22 are counted~
This e~fectively cancels any change in the rotary speed of disc 20.
One embodiment of pulse generator 30 now will be described with reference to the schematic diagram shown in FIGURE 2. The pulse generator is formed of complementary transistors 102 and 114.
A voltage divider circuit including resistors 104 and 106 is pro-vided between a source of operating potential ~V and a re~erence potential, such as ground. The output of this voltage divider circuit is connected to the emitter of transistor 102 to apply a predetermined bias voltage thereto. The collector of transistor 102 is connected through a resistor 108 and a rectiier 110 to the base of transistor 114. The emitter of transistor 114 is connected directly to the source +V and its base is connected to the source through a bias resistor 112. As shown, the collector o~ kransistor 114 is connected to ground through a load ~esistor 116, the output of pulse generator 30 being derived from the collector o transistor 114.
In operation, th~ base oE transistor 102 ls connected to ampll~ier 28 so as to receive the pulses produced in response to the rotation o~ reerence disc 20 as tape T moves. As exagge-rated in FIGURE 2, the leading and trailing edges of these pulses are not absolutely perpendicular and, therefore, exhLbit some degrèe of slope. When the leading edge of this pulse exceeds the bias voltage at the emitter of transistor 102 (plus the base-emitter voltage), transistor 102 is turned on and is driven toward saturation. Consequently, the collector voltage, which pre-viously had been equal to ~he source voltage ~v, applied through resistor 112, rectifier 110 and resistor 108, rapidly decreases to approximately the emitter bias voltage of transistor 102.
One of ordlnary skill in the art will appreciate that the base-collector junction of a transistor may be considered as including a diode poled to be reverse biased when the collector voltage exceeds the base voltage. However, as the leading edge of the pulse signal applied to transistor 102 continues to increase, this diode becomes forward biased. Hence, the voltage at the collector of transistor 102, which had been reduced to a lower level, now is driven in the positive direction by the inCreaSincJ
voltage applied to the base of this transistor. Therefore, the collector voltage of transistor 102 normally exhibits a higher voltage level, except during brief intervals that coincide with a portion o~ the rise time, or leading edge, of the pulsès ap-plied to the transistor.
A similar phenomenon occurs at the trailing edge of the pulse applied by amplifier 28. Thus, as this trailing edge decrea~es, transistor 102 is driven out o~ saturation and its base-collector diode becomes reverse biased. Accordingly, the collector voltage of transistor 102 i5 reduced ~o.r a brie:E inter-val, or until its base voltage no longer exceeds the bias voltage applied to its emitter (plus the base-emitter voltage). At that ::
tlme, transistor 102 is turned off. Hence, it is appreciated that the collector voltage of transistor la2 appears as a series oE negative-going impulses corresponding to the leading and trail-ing edges of the pulse signal applied thereto by amplifier 28.
These negative-going impulses are inverted by transistor 114 and then supplied to the remaining circuity illustrated in FIGURE 1.
While the present invention has been particularly shown in conjunction with a preferred embodiment thereof, it should be apparent that various modifications in form and details can be made without departing from the spirit and scope of the invention.
Some of these modifications and alternative embodiments have been described hereinabove. As another modification, counter 52 may be of the type having a second output terminal whereat a signal, such as a binary "1", is provided when the count exhibited by coun~r 52 changes from its initial count. This signal, rather ~han the signal produced by AMD gate 42, can be used to reset 1ip-flop circuit 66.
In addition, it should be recognized that, although this farthest advance apparatus can be used advantageously with a bi-directionally movable web, such as a tape housed in a cassette, or driven ~rom one reel to another, or forming an endless tape loop, the apparatus also can be used to .indicate
2~ th~ Ear~hast advance position oE any other medium or bi-direction-ally movable device. Furthermore, although one preferred embodi-ment o~ pulse generator 30 has been shown and described, it is ~ppaxen~ that various other pulse generators can be used, i:e da~.ixed, to produce relatively narrow pulse signals correspond-in~ to the transitions sensed by a suitable transducer as referenae ~19c 20 is driven.
Therefore, it is intended that the appended claims be interpreted as including the foregoing as well as other such changes and modifications.
Therefore, it is intended that the appended claims be interpreted as including the foregoing as well as other such changes and modifications.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for indicating the farthest advance position of a medium bi-directionally movable by a transport mechanism, comprising: means for providing a first signal when said transport mechanism is actuated to move said medium in a first direction; means for providing a second signal when said transport mechanism is actuated to move said medium in a second direc-tion opposite to said first direction; pulse generating means operable with said transport mechanism to generate pulses representing the amount that said medium moves either in said first or in said second direction; bi-directional counting means selectively responsive to each generated pulse to incremental-ly change the count thereof in a first or second direction; gating means for coupling said generated pulses to said counting means when said medium moves in said second direction so that said counting means incrementally changes its count from an initial count and in a first direction and for coupling said generated pulses to said counting means when said medium moves in said first direction following movement in said second direction so that said counting means incrementally changes its count in a second direction so as to be restored to said initial count; gate control means responsive to said first and second signals and to said generated pulses for energizing said gating means when said first or second signal is initiated in non-coincidence with a generated pulse and for maintaining said gating means energized if said first or second signal terminates but said pulses continue to be gener-ated; and output means for producing a farthest advance signal when said counting means is restored to said initial count and for maintaining said farthest advance signal until said medium subsequently is moved in said second direction.
2. The apparatus of claim 1 wherein said pulse generating means com-prises reference means movable in synchronism with said medium; sensing means for sensing the passage of said reference means past a sensing location and for generating pulses in response thereto; and pulse shaping means coupled to said sensing means for shaping said pulses to a predeter-mined configuration.
3. The apparatus of claim 2 wherein said sensing means comprises a light source in fixed position, and photoresponsive means in optical communication with said light source for producing an output proportional to the amount of light impinging thereon; said reference means comprises a disc rotatable in synchronism with said movement of said medium, said disc having spaced apart portions that are periodically interposed in the optical path between said light source and said photoresponsive means to correspondingly modulate the light impinging on said photoresponsive means;
and said pulse shaping means comprises transition sensing means for sensing transitions in the output pulses produced by said photoresponsive means and producing a transition pulse at each sensed transition.
and said pulse shaping means comprises transition sensing means for sensing transitions in the output pulses produced by said photoresponsive means and producing a transition pulse at each sensed transition.
4. The apparatus of claim 3 wherein said transition sensing means comprises first transistor means having base electrode means supplied with said output pulses produced by said photoresponsive means, emitter electrode means supplied with a predetermined bias potential, and collector electrode means direct coupled through rectifier means to base electrode means of second transistor means; and an output terminal direct coupled to said second transistor means whereat said transition pulses are derived.
5. The apparatus of claim 1 wherein said counting means comprises a reversible pulse counter having a first input for receiving pulses to incre-ment the count thereof, a second input for receiving pulses to decrement the count thereof, and at least one output for providing a representation of said count; and said gating means is coupled to said pulse generating means and is energized by said gate control means when the latter is responsive to said first signal for applying said pulses to said first input of said counter and is energized by said gate control means when the latter is responsive to said second signal for applying said pulses to said second input of said counter.
6. The apparatus of claim 5 wherein said counter includes an output for producing a first counter output signal when said counter is incremented to a predetermined count and a second counter output signal when said count is other than said predetermined count; and further comprising inhibit means coupled to said counter and responsive to said first counter output signal for inhibiting said counter from being further incremented by said pulses.
7. The apparatus of claim 5 wherein said gate control means comprises a first AND gate for receiving said first signal, a second AND gate for receiving said second signal, logic inverter means for supplying inverted pulses to said first and second AND gates, and bi-state means responsive to the first inverted pulse transmitted by said first AND gate for assuming a first state and responsive to the first inverted pulse transmitted by said second AND gate for assuming a second state, said first state energizing said gating means to apply succeeding non-inverted pulses to said first input of said counter and said second state energizing said gating means to apply succeeding non-inverted pulses to said second input of said counter.
8. Apparatus for indicating the farthest advance position of a bi-directionally driven web, comprising means for providing a first signal when said web is driven in a forward direction; means for providing a second signal when said web is driven in a reverse direction; a member rotatable in synchronism with said web and having periodically spaced reference portions;
sensing means fixedly disposed for sensing the passage therepast of each of said reference portions of said member and for generating reference pulses in response thereto; UP/DOWN counting means having a count up input for receiving reference pulses to increment the count of said counting means in response to each said pulse applied thereto, a count down input for receiv-ing reference pulses to decrement the count of said counting means in response to each said pulse applied thereto, and output means for producing a first counter output signal when the count of said counting means is a predetermined count and for producing a second counter output signal when said count is not said predetermined count; a first AND gate responsive to said first signal for applying said reference pulses to said count up input of said counting means; a second AND gate responsive to said second signal for applying said reference pulses to said count down input of said counting means; farthest advance signal means responsive to said first counter output signal for producing a farthest advance signal indicating that said web has reached its farthest advance position; and counter inhibit means responsive to said farthest advance signal for inhibiting said counting means from being incremented beyond said predetermined count while said farthest advance signal is produced.
23u
sensing means fixedly disposed for sensing the passage therepast of each of said reference portions of said member and for generating reference pulses in response thereto; UP/DOWN counting means having a count up input for receiving reference pulses to increment the count of said counting means in response to each said pulse applied thereto, a count down input for receiv-ing reference pulses to decrement the count of said counting means in response to each said pulse applied thereto, and output means for producing a first counter output signal when the count of said counting means is a predetermined count and for producing a second counter output signal when said count is not said predetermined count; a first AND gate responsive to said first signal for applying said reference pulses to said count up input of said counting means; a second AND gate responsive to said second signal for applying said reference pulses to said count down input of said counting means; farthest advance signal means responsive to said first counter output signal for producing a farthest advance signal indicating that said web has reached its farthest advance position; and counter inhibit means responsive to said farthest advance signal for inhibiting said counting means from being incremented beyond said predetermined count while said farthest advance signal is produced.
23u
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/722,142 US4092680A (en) | 1976-09-10 | 1976-09-10 | Apparatus for indicating the farthest advance position of a bi-directionally movable medium |
| US722,142 | 1976-09-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1089947A true CA1089947A (en) | 1980-11-18 |
Family
ID=24900674
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA286,427A Expired CA1089947A (en) | 1976-09-10 | 1977-09-09 | Apparatus for indicating the farthest advance position of a bi-directionally movable medium |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4092680A (en) |
| JP (1) | JPS6034173B2 (en) |
| CA (1) | CA1089947A (en) |
| DE (1) | DE2740824A1 (en) |
| GB (1) | GB1591252A (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE437307B (en) * | 1977-01-17 | 1985-02-18 | Matsushita Electric Ind Co Ltd | TAPE LENGTH INDICATING DEVICE ON TAPE RECORDERS |
| GB2003631B (en) * | 1977-08-30 | 1982-03-24 | Pioneer Electronic Corp | Magnetic tape running state and tape run amount display device |
| US4411008A (en) * | 1977-12-09 | 1983-10-18 | Staar S. A. | Method and apparatus for controlling tape transport apparatus in search sequence |
| NL7713709A (en) * | 1977-12-12 | 1979-06-14 | Philips Nv | MAGNETIC TAPE TRANSPORT SYSTEM AND MAGNETIC TAPE CASSETTE FOR A MAGNETIC TAPE TRANSPORTS SYSTEM AND MAGNETIC TAPE RECORDING AND / OR DISPLAY DEVICE EQUIPPED WITH A MAGNETIC TAPE TRANSPORT SYSTEM. |
| US4200893A (en) * | 1978-05-17 | 1980-04-29 | Dictaphone Corporation | Instruction indicating apparatus for a record and/or playback device |
| US4399527A (en) * | 1979-04-09 | 1983-08-16 | Lanier Business Products, Inc. | Dictation display device |
| US4352173A (en) * | 1979-04-09 | 1982-09-28 | Lanier Business Products, Inc. | Dictation display device |
| US4309571A (en) * | 1980-05-05 | 1982-01-05 | Dictaphone Corporation | Telephone-adapter apparatus for a dictation unit |
| DE3047918C2 (en) * | 1980-12-19 | 1982-10-21 | Compur-Electronic GmbH, 8000 München | Method and circuit arrangement for controlling an automatic telephone answering machine |
| US4398279A (en) * | 1981-05-04 | 1983-08-09 | Lanier Business Products, Inc. | Digital display for dictation transcriber for indicating remaining tape within discrete segments of dictation |
| JPS5942681A (en) * | 1982-09-02 | 1984-03-09 | Mitsubishi Electric Corp | Display device of tape quantity |
| JPS59124055A (en) * | 1982-12-29 | 1984-07-18 | Mitsubishi Electric Corp | Magnetic video recording and reproducing device |
| US4858213A (en) * | 1986-08-08 | 1989-08-15 | Dictaphone Corporation | Display for modular dictation/transcription system |
| US6687087B2 (en) * | 2001-10-11 | 2004-02-03 | International Business Machines Corporation | System and method for visually indicating usage of magnetic tape cartridges |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3467791A (en) * | 1967-03-08 | 1969-09-16 | Lanier Electronic Lab Inc | Device to indicate the net motion of a tape in one of two directions of travel |
| US3541271A (en) * | 1967-10-30 | 1970-11-17 | Chester Electronic Lab Inc | Dial operated search control for tape recorder |
| US3708633A (en) * | 1969-09-26 | 1973-01-02 | Lanier Electronic Lab Inc | Unidirectional tape motion detection apparatus and automatic tape return |
| US3821802A (en) * | 1970-08-03 | 1974-06-28 | Lanier Electronic Lab Inc | Tape movement indication means and signalling device |
| US3681523A (en) * | 1970-08-13 | 1972-08-01 | Ampex | Transport controller |
| US3757057A (en) * | 1972-03-17 | 1973-09-04 | Lanier Electronic Lab Inc | T of tape withdrawn from the supply reel recorder indexing apparatus with a cumulative indication of the amoun |
| US3823274A (en) * | 1973-01-10 | 1974-07-09 | Dictaphone Corp | Farthest advance circuit for a remote station dictating system |
| DE2337124A1 (en) * | 1973-07-20 | 1975-02-13 | Siemens Ag | Electronic determination of maximal and minimal values - of parameter during defined sequence of events uses analogue to digital converter |
| JPS5087314A (en) * | 1973-12-04 | 1975-07-14 | ||
| US3903369B2 (en) * | 1974-04-15 | 1991-03-05 | Telephone answering system with remote playback | |
| DE2449565C2 (en) * | 1974-10-18 | 1984-02-09 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Magnetic tape recorder with tape status indicator |
-
1976
- 1976-09-10 US US05/722,142 patent/US4092680A/en not_active Expired - Lifetime
-
1977
- 1977-09-09 GB GB37803/77A patent/GB1591252A/en not_active Expired
- 1977-09-09 CA CA286,427A patent/CA1089947A/en not_active Expired
- 1977-09-10 DE DE19772740824 patent/DE2740824A1/en active Granted
- 1977-09-10 JP JP52109391A patent/JPS6034173B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2740824A1 (en) | 1978-03-16 |
| US4092680A (en) | 1978-05-30 |
| JPS6034173B2 (en) | 1985-08-07 |
| DE2740824C2 (en) | 1988-05-11 |
| JPS5352109A (en) | 1978-05-12 |
| GB1591252A (en) | 1981-06-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1089947A (en) | Apparatus for indicating the farthest advance position of a bi-directionally movable medium | |
| US4336560A (en) | Pulse-operated mode switching mechanism for tape recorders | |
| US3293522A (en) | Motor drive circuits | |
| US4167764A (en) | Mode changing apparatus in a tape recorder | |
| US3895277A (en) | Electronic dynamic braking for tape recorder devices | |
| US4030131A (en) | Slack tape loader | |
| CA1122318A (en) | Web transport capstan control system | |
| US4163532A (en) | Tape speed control servomechanism for a magnetic tape cassette apparatus | |
| US3965484A (en) | Central dictation system | |
| US4367500A (en) | Tape end detection apparatus | |
| US4010917A (en) | Automatic stop device for a magnetic tape recording and/or playback apparatus | |
| US4302786A (en) | Apparatus for detecting the stop of a magnetic tape traveling in a magnetic recording and reproducing device | |
| CA1120148A (en) | Method and apparatus for controlling the movement of a recording medium | |
| US4577246A (en) | Cassette recording/reproducing apparatus with an automatic loading feed roller | |
| US4390918A (en) | Operating mode switching mechanism for a tape recorder | |
| US3641504A (en) | Apparatus for transporting a recording medium for storing information | |
| EP0154485A2 (en) | Video signal recording and/or reproducing apparatus having a function of carrying out assembled recordings | |
| US3842326A (en) | Velocity control system for reel-to-reel web drive | |
| US3690591A (en) | Remote control for recorders | |
| US4423443A (en) | Automatic-reversing tape deck | |
| GB1431967A (en) | Cassette tape recorder | |
| US3582568A (en) | Tape quick feed means for a sound reproducing apparatus utilizing a magnetic endless tape | |
| EP0030113B1 (en) | Recording-time mode detector and video tape recorder or reproducer including such a detector | |
| US3821802A (en) | Tape movement indication means and signalling device | |
| US3394854A (en) | Tape transport control circuits |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |