US2419999A - Orienting mechanism for pulse echo systems - Google Patents

Description

May 6, 1947. w, LECK 2,419,999

ORIENTING MECHANISM FOR PULSE ECHO SYSTEMS Original Filed June 14, 1941 PULJ E RECEIVER JP/VISE 41 7267747018 JP/Mss 04 ram/m me Mame Zinnentor fical qefiflcaii /r 58 attorneg Patented May 6 1947 JUNITE'D STATES P EN OFFICE I 419,999 I V ORIENTING MECHANISM-FQKPULSE cno V;SYSTEMS George Leck, Princeton Junction, N. J., as

1 sig'nor to Radio Corporation of America, a corporation of Delaware Original application June 14, 1 941, Serial,No. 398,057. Divided and this applicationjuly 27, 1942, Serial No. 452,392

4. Claims. (Cl.-a250-1:72)

. application is a division of my copending noid type motors I09 are-preferablymounted at application Serial No. 398,057; filed June 14, .1941, 120 intervals. The motorseach includeapolarentitled Qrienting mechanisms for pulse echo izedmagnetic armature or movable member III.

systems. The movable members -III areconnected by This :invention relates to scanning devices and .5 suitable links 3 to bearings H5 on the outer fiparticula'rly to improvements in devices for varyportion of the antenna reflector or other antenna the direction of a beam of energy from a member. The field coils of the motors are enerpulsetecho system and for directing in synchrogized by a three phase alternator I I1, which -is *nismtherewith the scanning beam of a cathode driven by a motor H9. The shaft I20 of the ray. indicator. alternator, or the driving motor I I9, is connected Pulse echosystems are used to detect objects through suitable gearing I2I to a rheostat I23 in and to indicate the direction-and distance of the the generator exciter circuit I24. The generator object. In such systems a directive antenna is output is thus varied according toany desired generally used for the pulse transmission and a pattern so that the three phase output voltage non-directive antenna-may servefor reception or follows, for example, a sawtooth pattern. The

vice versa, or directive antennas may be used for -motors I09 are successively energized by the three both transmission and reception. phase currents so that the antenna system under- While separate antennas may be used, the ingoes a circular rocking movement of an amplistant invention is described by referring to a tude varying according to the generator output. single directive antenna which may be used for The resulting antenna beam deflections follow a both transmission and reception. Such an anspiral pattern. That is, as the applied'voltages tenna system is described in the copending apincrease, because of the sawtooth wave form of plication Serial No. 184,354, filed January 11, the generator exciting voltage, the motors I09 1938, by Wolff and Hershberger for Signaling produce larger and larger movements and since system. the movements are preferably at 120 intervals in One of the objects of the instant invention is space and in time, the axis I26 of the antenna to provide improved means for scanning aregion I28 traces a helical pattern and the beam of by a beam of pulse energy. Another object is pulses from the antenna scan a, conical or hemito provide improved means for moving a beam of spherical region. The antenna system is conpulse energy and a cathode ray beam in synnected by a transmission line 49 to a pulse transchronism. Another object is to provide means mitter 5| and to a pulse receiver 53. The output for directing a beam of pulses throughout a conof the pulse receiver is applied to the control ical region and for synchronously directing a electrodes of the cathode ray tube I32 so that cathode ray beam in a helical pattern. received signals may brighten or dim the cathode The invention will be described by referring ray trace. The three phase currents may be apto the accompanying drawing, of which Fig. 1 is plied to a three coil deflecting system I30 ara schematic diagram of one embodiment providranged around the cathode ray indicator I32 to ing an electro-mechanical scanning, and Fig. 2 is rotate the cathode ray in synchronism with the a circuit diagram of a modification of Fig. 1, rotations of the antenna, and the sawtooth volt- Similar reference characters are applied to ages may be applied to produce radial movesimilar elements throughout the drawing. ments. The cathode ray will trace a helical pat- In my co-pending application, of which this tern on the fluorescent screen of the indicator, application is a division, there i described a mewhich may be provided with a suitable calibrated chanical system whereby a directive antenna is scale I34 to indicate the position of the reflectcaused to traverse a conical region. The connecing object with respect to predetermined cotions to the antenna from the pulse transmitting ordinates.

and receiving apparatus may be made as de- Instead of using polarized magnetic armatures scribed in the copending application of Wolff and in the solenoid motors I09 and applying sawtooth Hershberger mentioned heretofore. Fig. 1 proexciting voltages to the three phase generator, vides an electro-mechanical drive for actuating 59 the movable motor members III may be consist of the scanning mechanism of the directional ana second solenoid II2 to which the sawtooth tenna system. The directive antenna system IIII voltages from the potentiometer I23 may be apis mounted in a ball and socket or other universal plied. Under these circumstances, the three joint I03 which is supported by a post I05 exphase currents are applied, as shown in Fig. 2 tending from the base member I01. Three soleto the fixed windings and the direct currents are applied to the movable windings, or vice versa, so that the antennas will be deflected by variable amounts so that its axis follows a helical path as before. In either arrangement the connecting rods may be provided with biasing springs I25 to maintain. the zero or central position of the antenna, which has been omitted to avoid com plicating the diagram.

Thus the invention has been described as an improved means for scanning aregion by means of a beam of pulses. A cathode ray is moved in synchronism with the scanningbeam. Received pulse echoes are applied to modulate or vary the cathode ray so that an object will be indicated according to predeterminedcoordinates on the cathode ray tube screen. In this manner the sky from the horizon upwardly may be continuously scanned and reflections from an aircraft or surface vessel coming over the horizon will indicate the azimuth and elevation of the craft.

I claim as my invention:

1. A pulse echo scanning device including, in

combination, a directive antenna for radiating a beam of pulses and for receiving echo pulses from objects in said beam, a universal joint for supporting said antenna, three solenoid type motor each including a field winding and a movable member, means connecting said movable members to said antenna so that upon energizing said motors from a three phase source said antenna will follow a circular rocking movement, a radio receiver connected to said antenna and responsive to said echo pulses, a cathode ray indicator connected to said receiver for indicating said echo pulses, and means for deflecting said cathode ray in synchronism with said circular rocking movement.

2. A device according to claim 1 including means for varying the amount of energy applied to said motors so that the amplitude of said circular rocking movement is correspondingly varied. 3. A radio beam scanning device including an antenna system for establishing a sharply defined beam, a universal mounting for supporting said antenna system, three solenoid type motors each including a field winding and a movable member, means connecting said movable members to said antenna system, and means for energizing said motors from a three phase source so that said antenna will follow a circular rocking move- .ment.

4. A device according to claim 3 including means for varying the amplitude of said circular rocking movement.

GEORGE W. LECK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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