WO2007149279A2 - Amplified stethoscope with automatic noise reduction signal processing - Google Patents
Amplified stethoscope with automatic noise reduction signal processing Download PDFInfo
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- WO2007149279A2 WO2007149279A2 PCT/US2007/013865 US2007013865W WO2007149279A2 WO 2007149279 A2 WO2007149279 A2 WO 2007149279A2 US 2007013865 W US2007013865 W US 2007013865W WO 2007149279 A2 WO2007149279 A2 WO 2007149279A2
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B7/00—Instruments for auscultation
- A61B7/02—Stethoscopes
- A61B7/04—Electric stethoscopes
Definitions
- the present invention relates to stethoscopes, and more specifically to amplified stethoscopes comprising noise elimination signal processing.
- Both acoustic and amplified stethoscopes comprise a pickup head that is placed upon a patient.
- the pickup head detects anatomical sounds emanating from within the patient that are of interest to a practitioner using the stethoscope; however the pickup head also delects pickup head vibration artifact noise and external ambient noise.
- Pickup head vibration artifact noise is typically short in duration (generally occurring during the first few seconds following pickup head placement on the patient) but can be extremely high in level with respect to the detected anatomical sounds.
- the pickup head is passive and couples the detected sounds and noises (the "detected sounds") via air confined within two hollow tubes to two open earpieces inserted in the ears of a practitioner.
- the pickup head is active and couples the detected sounds to a microphone comprised in such pickup head; such microphone provides an input signal to a signal processor and amplifier; such signal processor and amplifier provide an amplified output signal that is connected to a speaker driver; and such speaker driver produces amplified detected sounds that couple via air confined with hollow tubes to two open earpieces inserted in the ears of a practitioner.
- signal processors comprised prior art amplified stethoscopes may employ (a) multiple filter options, in which at least one upper cut-off frequency typically on the order of 1 ,000 to 3,000 Hz may be selected, and/or (b) multiple frequency response equalization options, in which at least one frequency response equalization curve may be selected.
- Such options are selected manually by the practitioner often while the practitioner simultaneously attempts to use, and hold steady the position of, the pickup head on a patient in order to minimize pickup head movement artifact noise - a task which, from a practical standpoint, is often difficult to implement.
- Other prior art amplified stethoscopes utilize a secondary ambient noise detection microphone having an output signal that is subtracted from a primary stethoscope microphone output signal in such a manner as to reduce ambient noise levels in the primary stethoscope microphone signal.
- noise reduction techniques are often not sufficiently effective due to phase and amplitude misalignments of noise signals in the primary and secondary microphones for varying acoustic noise source and primary microphone placement parameters.
- prior art acoustic stethoscopes offer the advantages of low cost and simplicity of operation, however inherently present low volume levels of detected sounds to the practitioner.
- Prior art amplified stethoscopes offer the advantage of presenting high volume levels of detected sounds to the practitioner, however are inherently limited by at least one, and typically all, of the following disadvantages: [004] 1. Excessive amplification of pickup head vibration artifact noise relative to the detected anatomical sounds.
- the present invention is an amplified stethoscope (“the stethoscope”) that provides effective, and where applicable automated, resolutions to inherent limitations in prior art amplified stethoscopes.
- the stethoscope comprises a main body that incorporates a signal processor and amplifier coupled to a pickup head that is placed upon a patient.
- a first microphone is disposed within the pickup head and provides a first microphone signal that is processed by the signal processor.
- the first microphone signal corresponds to detected anatomical sound emanating from within the patient (the "anatomical sound”), which sounds are of diagnostic interest to a practitioner using the stethoscope; however, such signal also corresponds to detected pickup head movement induced artifact noise (the “artifact noise”) and competing external ambient noise (the “ambient noise”), which noises, once amplified, are disturbing and distracting to a practitioner using the stethoscope.
- Artifact noise is typically short in duration (typically occurring only during the first few seconds following placement or movement of the pickup head on the patient) and is typically high in amplitude with respect to the anatomical sounds.
- Ambient noise may exist for extended durations and is typically moderate in amplitude with respect to the anatomical sounds.
- the first microphone signal thereby corresponds to each of the anatomical sounds, the artifact noise and the ambient noise (collectively, the "detected sounds").
- the signal processor provides a processor audio output signal that is applied to at least one amplifier, which in turn provides at least one amplified output signal connected to at one of
- At least one but ordinarily two speaker drivers producing amplified detected sounds which couple to a pair of air-filled hollow tubes substantially 200 to 400 mm in length, each such tube inserted into an ear of a practitioner ordinarily by means of a flexible earpiece, or, preferably,
- the signal processor receives as input and processes the first microphone signal and provides at least one function of (a) a first signal process comprising a squelch, by means of one of disabling or attenuating the processor audio output signal during at least one of the typically short durations of high amplitude artifact noise above a first amplitude threshold, or an increasing rate of change in such artifact noise above a first rate of change threshold, wherein at least one of the activation or non-activation of the squelch, in the above- described manner, may be indicated by a first visual display, such as LED light(s), preferably disposed on the pickup head and driven by a signal processor display output signal, thereby providing the practitioner with visual feedback as to when the pickup head is being held in a stable position on the patient such that artifact noise induced
- a second microphone may be disposed in the pickup head in such a manner as to be directly exposed to the ambient noise and provides a second microphone signal that augments the first microphone signal as input to the signal processor, wherein only the second microphone signal applies to the third signal process.
- a binaural summation control may be comprised in one of the signal processor or amplifier, in which asymmetrical adjustments of such control present corresponding asymmetrical amplitude ratios of detected sounds to left and right amplifiers and earpieces in order to compensate for potential asymmetrical hearing sensitivities of the practitioner, whereby such adjustments may be indicated by a fourth visual display preferably disposed on the pickup head.
- Such binaural summation control enables optimization of binaural summation and enhanced clarity of the detected anatomical sound.
- Volume and power controls are also comprised in the stethoscope.
- FIG. 1 is a block diagram of a prior art amplified stethoscope.
- FIG. 2 is a block diagram of the preferred embodiment of a stethoscope of the present invention.
- FIG. 3 is a block diagram of an alternative embodiment of a stethoscope of the present invention.
- FIG. 1 is a block diagram of a prior art amplified stethoscope, in which microphone Ml is disposed on a first side 1 of pickup head H l, whereby side 1 of Hl may be placed against a patient and Ml detects anatomical sound, pickup head movement artifact noise and ambient noise (collectively, the detected sounds).
- Ml provides microphone output signal Sl, which is applied as input to signal processor SPl .
- SPl provides signal process P2 consisting of a filter having an upper frequency cut-off, and signal process P8 consisting of a frequency response equalization curve.
- SPl provides signal processor output signal S2, which is applied as input to amplifier Ql.
- Hollow tube Tl has a length dimension of substantially 200 to 400 mm, a front section sealingly coupled to Dl, and splits into a first rear section sealingly coupled to earpiece El and into a second rear section sealingly coupled to earpiece E2, whereby the amplified detected sound is confined and radiates to the earpieces.
- Main body MBl houses SPl, Ql, Dl and a front section of Tl, while Hl, Ml, El, E2 and a rear section of Tl lie outside of MBl.
- FIG. 3 is a block diagram of the preferred embodiment of a stethoscope of the present invention, in which microphone M5 is disposed on a first side 1 of pickup head H3, whereby side 1 of H3 is placed against and is directed toward a patient and M5 detects anatomical sound, pickup head movement artifact noise and ambient noise (collectively, the detected sounds).
- M5 provides microphone output signal S13, which is applied as a first input to signal processor SP3.
- Microphone M6 is disposed on a second side 2 of pickup head H3, whereby side 2 of H3 is directed away from such patient and whereby M6 detects ambient noise.
- M6 provides microphone output signal S14, which is applied as a second input to signal processor SP3.
- SP3 provides signal process Pl consisting of a detected signal squelch function, signal process P2 consisting of a filter having an upper frequency cut-off, signal process P3 consisting of a decrementing of the filter in the second signal process, signal process P4 consisting of a default function of the first signal process, signal process P5 consisting of a default function of the third signal process, signal process P6 consisting of a limiting or compression of the detected sounds, signal process P7 consisting of a high pass filter having a lower cut-off frequency, and signal process P8 consisting of a frequency response equalization curve.
- SP3 provides signal processor audio output signal S16, which is applied as input to amplifier Q3 comprising a binaural summation control.
- Q3 provides first amplified output signal S 17, which is applied as input to speaker driver D4 producing a first amplified detected sound.
- Q3 further provides second amplified output signal S18, which is applied as input to speaker driver D5 producing a second amplified detected sound.
- Hollow tube T4 has a length dimension of substantially 200 to 400 mm, a front section sealingly coupled to D4, and a rear section sealingly coupled to earpiece E5.
- Hollow tube T5 has a length dimension of substantially 200 to 400 mm, a front section sealingly coupled to D5, and a rear section sealingly coupled to earpiece E6.
- the first and second amplified detected sounds are thereby confined and radiate to E5 and E6 respectively.
- SP3 provides signal processor light display output signal S15, which is applied to light displays L4, L5 and L6, which indicate the status of the first and third signal processes and the binaural summation control.
- Main body MB3 houses SP3, Q3, D4. D5, and front sections of T4 and T5, while E5, E6 and rear sections of T4 and T5 lie outside of MB3.
- FIG. 3 is a block diagram of an alternative embodiment of a stethoscope of the present invention, in which microphone M7 is disposed on a first side J of pickup head H4, whereby side 1 of H4 may be placed against a patient and M7 detects anatomical sound, pickup head movement artifact noise and ambient noise (collectively, the detected sounds). M7 provides microphone output signal S19, which is applied as input to signal processor SP4.
- SP4 provides signal process Pl consisting of a detected signal squelch function, signal process P2 consisting of a filter having an upper frequency cut-off, signal process P3 consisting of a decrementing of the filter in the second signal process, signal process P4 consisting of a default function of the first signal process, signal process P5 consisting of a default function of the third signal process, signal process P6 consisting of a limiting or compression of the detected sounds, signal process P7 consisting of a high pass filter having a lower cut-off frequency, and signal process P8 consisting of a frequency response equalization curve.
- SP4 provides signal processor audio output signal S21, which is applied as input to amplifier Q4 comprising a binaural summation control.
- Q4 provides first amplified output signal S22, which is applied as input to speaker driver D6 producing a first amplified detected sound.
- Q4 further provides second amplified output signal S23, which is applied as input to speaker driver D7 producing a second amplified detected sound.
- Hollow tube T6 has a length dimension of substantially 1 to 2 mm, a front section sealingly coupled to D6, and a rear section sealingly coupled to earpiece E7.
- Hollow tube T7 has a length dimension of substantially 1 to 2 mm, a front section sealingly coupled to D7, and a rear section sealingly coupled to earpiece E8.
- the first and second amplified detected sounds are thereby confined and radiate to E7 and E8 respectively.
- SP4 provides signal processor light display output signal S20, which is applied to light displays L7, L8 and L9, which indicate the status of the first and third signal processes and the binaural summation control.
- Main body MB4 houses SP4, and Q4, while H4, M7, D6, D7, T6, T7, E7 and E8 lie outside of MBl.
Abstract
An amplified stethoscope comprising multiple novel signal processes, in which pickup head movement induced artifact noise is squelched, competing external ambient noise is minimized, anatomical sounds are normalized, binaural summation is optimized, and, where applicable, such processes are provided in an automated manner.
Description
AMPLIFIED STETHOSCOPE WITH AUTOMATIC NOISE REDUCTION SIGNAL PROCESSING
FIELD OF THE INVENTION
[001] The present invention relates to stethoscopes, and more specifically to amplified stethoscopes comprising noise elimination signal processing.
BACKGROUND OF THE INVENTION
[002] Existing stethoscopes fall into two general categories — acoustic and amplified. Both acoustic and amplified stethoscopes comprise a pickup head that is placed upon a patient. The pickup head detects anatomical sounds emanating from within the patient that are of interest to a practitioner using the stethoscope; however the pickup head also delects pickup head vibration artifact noise and external ambient noise. Pickup head vibration artifact noise is typically short in duration (generally occurring during the first few seconds following pickup head placement on the patient) but can be extremely high in level with respect to the detected anatomical sounds. External ambient noise may exist for extended durations but is generally only moderately high in level with respect to the detected anatomical sounds; however, both of the above noises are commonly considered disturbing and distract hearing attention of the practitioner from the anatomical sounds. In the case of acoustic stethoscopes, the pickup head is passive and couples the detected sounds and noises (the "detected sounds") via air confined within two hollow tubes to two open earpieces inserted in the ears of a practitioner. In the case of amplified stethoscopes, the pickup head is active and couples the detected sounds to a microphone comprised in such pickup head; such microphone provides an input signal to a signal processor and amplifier; such signal processor and amplifier provide an amplified output signal that is connected to a speaker driver; and such speaker driver produces amplified detected sounds that couple via air confined with hollow tubes to two open earpieces inserted in the ears of a practitioner. Such signal
processors comprised prior art amplified stethoscopes may employ (a) multiple filter options, in which at least one upper cut-off frequency typically on the order of 1 ,000 to 3,000 Hz may be selected, and/or (b) multiple frequency response equalization options, in which at least one frequency response equalization curve may be selected. Such options are selected manually by the practitioner often while the practitioner simultaneously attempts to use, and hold steady the position of, the pickup head on a patient in order to minimize pickup head movement artifact noise - a task which, from a practical standpoint, is often difficult to implement. Other prior art amplified stethoscopes utilize a secondary ambient noise detection microphone having an output signal that is subtracted from a primary stethoscope microphone output signal in such a manner as to reduce ambient noise levels in the primary stethoscope microphone signal. In practice, however, such noise reduction techniques are often not sufficiently effective due to phase and amplitude misalignments of noise signals in the primary and secondary microphones for varying acoustic noise source and primary microphone placement parameters.
[003] In general, prior art acoustic stethoscopes offer the advantages of low cost and simplicity of operation, however inherently present low volume levels of detected sounds to the practitioner. Prior art amplified stethoscopes offer the advantage of presenting high volume levels of detected sounds to the practitioner, however are inherently limited by at least one, and typically all, of the following disadvantages: [004] 1. Excessive amplification of pickup head vibration artifact noise relative to the detected anatomical sounds.
[005] 2. Excessive amplification of ambient noise relative to the detected anatomical sounds when signal processed by a filter option having a high upper cut-off frequency. [006] 3. Excessive variations in acoustic intensity of the detected anatomical sounds as
a function of such variables as tissue type and depth of the anatomical sounds. [007] 4. Necessity to manually select the signal process functions such as filter upper and/or lower cut-off frequencies while simultaneously using the stethoscope. [008j 5. Lack of a visual display indicating that the pickup head is sufficiently stable on the patient to minimize pickup head vibration artifact noise.
[009J 6. Lack of a visual display indicating that real time ambient noise is sufficiently low to enable effective monitoring of detected anatomical sounds.
[010] 7. Non-adjustable binaural summation as presented to the left and right ears and corresponding non-optimal audio clarity of detected anatomical sounds. [011] 8. Lack of direct-to-ear coupled speaker drivers disposed adjacent to the ears of the practitioner and therefore non-optimized audio clarity of detected anatomical sounds. [012] 9. Lack of a wireless link between a remote pickup head and the stethoscope preferably wherein the pickup head may be removably disposed on the stethoscope.
[013] A need therefore exists for an amplified stethoscope comprising novel signal processes and features that provide effective, and where applicable automated, features and solutions to the above limitations of prior art amplified stethoscopes.
SUMMARY OF THE INVENTION [014] The present invention is an amplified stethoscope ("the stethoscope") that provides effective, and where applicable automated, resolutions to inherent limitations in prior art amplified stethoscopes. The stethoscope comprises a main body that incorporates a signal processor and amplifier coupled to a pickup head that is placed upon a patient. A first microphone is disposed within the pickup head and provides a first microphone signal that is
processed by the signal processor. The first microphone signal corresponds to detected anatomical sound emanating from within the patient (the "anatomical sound"), which sounds are of diagnostic interest to a practitioner using the stethoscope; however, such signal also corresponds to detected pickup head movement induced artifact noise (the "artifact noise") and competing external ambient noise (the "ambient noise"), which noises, once amplified, are disturbing and distracting to a practitioner using the stethoscope. Artifact noise is typically short in duration (typically occurring only during the first few seconds following placement or movement of the pickup head on the patient) and is typically high in amplitude with respect to the anatomical sounds. Ambient noise, however, may exist for extended durations and is typically moderate in amplitude with respect to the anatomical sounds. The first microphone signal thereby corresponds to each of the anatomical sounds, the artifact noise and the ambient noise (collectively, the "detected sounds").
[0151 The signal processor provides a processor audio output signal that is applied to at least one amplifier, which in turn provides at least one amplified output signal connected to at one of
(1) at least one but ordinarily two speaker drivers producing amplified detected sounds, which couple to a pair of air-filled hollow tubes substantially 200 to 400 mm in length, each such tube inserted into an ear of a practitioner ordinarily by means of a flexible earpiece, or, preferably,
(2) a pair of speaker drivers producing amplified detected sounds, each disposed in close proximity to, and inserted in, an ear of a practitioner ordinarily by means a flexible earpiece substantially 1 to 2 mm in length. The signal processor receives as input and processes the first microphone signal and provides at least one function of (a) a first signal process comprising a squelch, by means of one of disabling or attenuating the processor audio output signal during at least one of the typically short durations of high amplitude artifact noise above a first amplitude
threshold, or an increasing rate of change in such artifact noise above a first rate of change threshold, wherein at least one of the activation or non-activation of the squelch, in the above- described manner, may be indicated by a first visual display, such as LED light(s), preferably disposed on the pickup head and driven by a signal processor display output signal, thereby providing the practitioner with visual feedback as to when the pickup head is being held in a stable position on the patient such that artifact noise induced squelch is one of activated or non- activated, (b) a second signal process comprising a low pass filter having at least two processor- selectable upper cut-off frequencies, the first such frequency lying between 500 Hz and 1 ,500- Hz, the second such frequency lying between 1 ,500 Hz and 5,000 Hz, and in the preferred embodiment substantially 500 Hz and 2,000 Hz for the first and second upper cut-off frequencies, respectively, (c) a third signal process comprising a decrementing of the selectable upper cut-off frequencies during at least one of ambient noise above a second amplitude threshold, or an increasing rate of change in such ambient noise above a second rate of change threshold, and further an incrementing of the selectable upper cut-off frequencies during at least one of an absence of ambient noise above the second threshold, or a decreasing rate of change in such ambient noise above the second rate of change threshold, wherein the corresponding selectable upper cut-off frequencies may be indicated by a second visual display, such as LED light(s), preferably disposed on the pickup head and driven by the signal processor display output signal, (d) a fourth signal process whereby a squelch active state (in accordance with the first signal process) defaults after a first predetermined time period to an immediately previous squelch inactive state, (e) a fifth signal process whereby a low range upper cut-off frequency (in accordance with the third signal process) defaults after a second predetermined time period to an immediately previous high range upper cut-off frequency state, (f) a sixth signal process comprising at least one of limiting or compressing the detected sounds, whereby anatomical
sounds having differing amplitudes as a function of such factors as tissue type and tissue depth between the first microphone and the source of such anatomical sound within the patient, are one of partially or completely normalized, (g) a seventh signal process comprising a high pass filter having a cut-off frequency typically between substantially 20 and 100 Hz, whereby the typically excessive intensity of extremely low frequency anatomical sounds, such as the fundamental frequency sound components of heart beats, are attenuated, and (h) an eighth signal process comprising at least one selectable frequency response equalization curve, which frequency response may be indicated by a third visual display. A second microphone may be disposed in the pickup head in such a manner as to be directly exposed to the ambient noise and provides a second microphone signal that augments the first microphone signal as input to the signal processor, wherein only the second microphone signal applies to the third signal process. A binaural summation control may be comprised in one of the signal processor or amplifier, in which asymmetrical adjustments of such control present corresponding asymmetrical amplitude ratios of detected sounds to left and right amplifiers and earpieces in order to compensate for potential asymmetrical hearing sensitivities of the practitioner, whereby such adjustments may be indicated by a fourth visual display preferably disposed on the pickup head. Such binaural summation control enables optimization of binaural summation and enhanced clarity of the detected anatomical sound. Volume and power controls are also comprised in the stethoscope.
BRIEF DESCRIPTION OF THE DRAWINGS
[016) FIG. 1 is a block diagram of a prior art amplified stethoscope.
[017J FIG. 2 is a block diagram of the preferred embodiment of a stethoscope of the present invention.
[018] FIG. 3 is a block diagram of an alternative embodiment of a stethoscope of the present
invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[019] FIG. 1 is a block diagram of a prior art amplified stethoscope, in which microphone Ml is disposed on a first side 1 of pickup head H l, whereby side 1 of Hl may be placed against a patient and Ml detects anatomical sound, pickup head movement artifact noise and ambient noise (collectively, the detected sounds). Ml provides microphone output signal Sl, which is applied as input to signal processor SPl . SPl provides signal process P2 consisting of a filter having an upper frequency cut-off, and signal process P8 consisting of a frequency response equalization curve. SPl provides signal processor output signal S2, which is applied as input to amplifier Ql. Ql provides amplified output signal S3, which is applied as input to speaker driver Dl producing an amplified detected sound. Hollow tube Tl has a length dimension of substantially 200 to 400 mm, a front section sealingly coupled to Dl, and splits into a first rear section sealingly coupled to earpiece El and into a second rear section sealingly coupled to earpiece E2, whereby the amplified detected sound is confined and radiates to the earpieces.
Main body MBl houses SPl, Ql, Dl and a front section of Tl, while Hl, Ml, El, E2 and a rear section of Tl lie outside of MBl.
[020] FIG. 3 is a block diagram of the preferred embodiment of a stethoscope of the present invention, in which microphone M5 is disposed on a first side 1 of pickup head H3, whereby side 1 of H3 is placed against and is directed toward a patient and M5 detects anatomical sound, pickup head movement artifact noise and ambient noise (collectively, the detected sounds). M5 provides microphone output signal S13, which is applied as a first input to signal processor SP3. Microphone M6 is disposed on a second side 2 of pickup head H3, whereby side 2 of H3 is
directed away from such patient and whereby M6 detects ambient noise. M6 provides microphone output signal S14, which is applied as a second input to signal processor SP3. SP3 provides signal process Pl consisting of a detected signal squelch function, signal process P2 consisting of a filter having an upper frequency cut-off, signal process P3 consisting of a decrementing of the filter in the second signal process, signal process P4 consisting of a default function of the first signal process, signal process P5 consisting of a default function of the third signal process, signal process P6 consisting of a limiting or compression of the detected sounds, signal process P7 consisting of a high pass filter having a lower cut-off frequency, and signal process P8 consisting of a frequency response equalization curve. SP3 provides signal processor audio output signal S16, which is applied as input to amplifier Q3 comprising a binaural summation control. Q3 provides first amplified output signal S 17, which is applied as input to speaker driver D4 producing a first amplified detected sound. Q3 further provides second amplified output signal S18, which is applied as input to speaker driver D5 producing a second amplified detected sound. Hollow tube T4 has a length dimension of substantially 200 to 400 mm, a front section sealingly coupled to D4, and a rear section sealingly coupled to earpiece E5.
Hollow tube T5 has a length dimension of substantially 200 to 400 mm, a front section sealingly coupled to D5, and a rear section sealingly coupled to earpiece E6. The first and second amplified detected sounds are thereby confined and radiate to E5 and E6 respectively. SP3 provides signal processor light display output signal S15, which is applied to light displays L4, L5 and L6, which indicate the status of the first and third signal processes and the binaural summation control. Main body MB3 houses SP3, Q3, D4. D5, and front sections of T4 and T5, while E5, E6 and rear sections of T4 and T5 lie outside of MB3.
[021] FIG. 3 is a block diagram of an alternative embodiment of a stethoscope of the present
invention, in which microphone M7 is disposed on a first side J of pickup head H4, whereby side 1 of H4 may be placed against a patient and M7 detects anatomical sound, pickup head movement artifact noise and ambient noise (collectively, the detected sounds). M7 provides microphone output signal S19, which is applied as input to signal processor SP4. SP4 provides signal process Pl consisting of a detected signal squelch function, signal process P2 consisting of a filter having an upper frequency cut-off, signal process P3 consisting of a decrementing of the filter in the second signal process, signal process P4 consisting of a default function of the first signal process, signal process P5 consisting of a default function of the third signal process, signal process P6 consisting of a limiting or compression of the detected sounds, signal process P7 consisting of a high pass filter having a lower cut-off frequency, and signal process P8 consisting of a frequency response equalization curve. SP4 provides signal processor audio output signal S21, which is applied as input to amplifier Q4 comprising a binaural summation control. Q4 provides first amplified output signal S22, which is applied as input to speaker driver D6 producing a first amplified detected sound. Q4 further provides second amplified output signal S23, which is applied as input to speaker driver D7 producing a second amplified detected sound. Hollow tube T6 has a length dimension of substantially 1 to 2 mm, a front section sealingly coupled to D6, and a rear section sealingly coupled to earpiece E7. Hollow tube T7 has a length dimension of substantially 1 to 2 mm, a front section sealingly coupled to D7, and a rear section sealingly coupled to earpiece E8. The first and second amplified detected sounds are thereby confined and radiate to E7 and E8 respectively. SP4 provides signal processor light display output signal S20, which is applied to light displays L7, L8 and L9, which indicate the status of the first and third signal processes and the binaural summation control. Main body MB4 houses SP4, and Q4, while H4, M7, D6, D7, T6, T7, E7 and E8 lie outside of MBl.
Claims
1. An amplified stethoscope comprising a first microphone disposed on a first side of a pickup head, such first side placed upon and at times moved about a patient, the first microphone providing a first microphone signal comprising (a) a desirable signal component corresponding to detected anatomical sounds emanating from within such patient, (b) an undesirable signal component corresponding to pickup head movement artifact noises resulting from movement of the pickup head about the patient, and (c) an undesirable signal component corresponding to competing external ambient noises, wherein the first microphone signal is applied as a first input to a signal processor providing a processed signal, the processed signal is applied as input to at least one amplifier providing at least one amplified signal, and the at least one amplified signal is applied to at least one transducer comprised in at least one earpiece, wherein the signal processor applies to the first microphone signal at least one function of; a first signal process of a squelch function that assumes an active state, by at least one of disabling and attenuating the processed signal, during at least one of (a) an artifact noise component in the first microphone signal above a first amplitude threshold, and (b) an increasing rate of change in amplitude of such artifact noise component above a first rate of change threshold; a second signal process of a low pass filter function having at least two processor- selectable upper cut-off frequencies; a third signal process in which a decrementing of the processor-selectable upper cut-off frequency occurs during at least one of (a) an ambient noise component in the first microphone signal above a second amplitude threshold, and (b) an increasing rate of change in such ambient noise component above a second rate of change threshold, and further in which an incrementing of the processor-selectable upper cut-off frequency occurs during at least one of (c) an absence of an ambient noise component in the first microphone signal above such second amplitude threshold, and (d) a decreasing rate of change in such ambient noise component above such second rate of change threshold; a fourth signal process in which an active squelch state, in accordance with the first signal process, defaults after a first predetermined time period to an immediately previous squelch inactive state; a fifth signal process in which a low region upper cut-off frequency, in accordance with the third signal process, defaults after a second predetermined time period to an immediately previous high region upper cut-off frequency state; a sixth signal process comprising at least one of limiting and compressing the amplitude of the first microphone signal; a seventh signal process of a high pass filter having a cut-off frequency lying between substantially 20 Hz and substantially 100 Hz; an eighth signal process of at least one selectable frequency response equalization curve, and a binaural summation control whereby the processor signal is applied with controllable amplitude ratio adjustments to left and right amplifiers operating left and right transducers and earpieces.
2. An amplified stethoscope comprising a first microphone disposed on a first side of a pickup head, such first side placed upon and at times moved about a patient, the first microphone providing a first microphone signal comprising (a) a desirable signal component corresponding to detected anatomical sounds emanating from within such patient, (b) an undesirable signal component corresponding to pickup head movement artifact noises resulting from movement of the pickup head about the patient, and (c) an undesirable signal component corresponding to competing external ambient noises, wherein the first microphone signal is applied as a first input to a signal processor providing a processed signal, the processed signal is applied as input to at least one amplifier providing at least one amplified signal, and the at least one amplified signal is applied to at least one transducer comprised in at least one earpiece, wherein the signal processor applies to the first microphone signal at least one function of; an amplifier providing an amplified signal, and the amplified signal is applied to at least one sound transducer comprised in at least one earpiece, and further wherein the signal processor applies to the first microphone signal at least one function of; a first signal process of a squelch function that assumes an active state, by at least one of disabling and attenuating the processed signal, during at least one of (a) an artifact noise component in the first microphone signal above a first amplitude threshold, and (b) an increasing rate of change in amplitude of such artifact noise component above a first rate of change threshold, and wherein such active state is indicated by a first visual display; a second signal process of a low pass filter function having at least two processor- selectable upper cut-off frequencies, the first such frequency lying in a low region between substantially 500 Hz and substantially 1 ,500 Hz, and the second such frequency lying in a high region between substantially 1,500 Hz and substantially 5,000 Hz; a third signal process in which a decrementing of the processor-selectable upper cut-off frequency occurs during at least one of (a) an ambient noise component in the first microphone signal above a second amplitude threshold, and (b) an increasing rate of change in such ambient noise component above a second rate of change threshold, and further in which an incrementing of the processor-selectable upper cut-off frequency occurs during at least one of (c) a substantial absence of an ambient noise component in the first microphone signal above such second amplitude threshold, and (d) a decreasing rate of change in such ambient noise component above such second rate of change threshold, and wherein at least one of a low region and a high region selectable upper cut-off frequency is indicated by a second visual display; a fourth signal process in which an active squelch state, in accordance with the first signal process, defaults after a first predetermined time period to an immediately previous squelch inactive state; a fifth signal process in which a low region upper cut-off frequency, in accordance with the third signal process, defaults after a second predetermined time period to an immediately previous high region upper cut-off frequency state; a sixth signal process comprising at least one of limiting and compressing the first microphone signal; a seventh signal process of a high pass filter having a cut-off frequency lying between substantially 20 Hz and substantially 100 Hz; an eighth signal process of at least one selectable frequency response equalization curve, which frequency responses are indicated by a third visual display, and a binaural summation control whereby the processor signal is applied with controllable amplitude ratio adjustments to left and right amplifiers operating left and right transducers and earpieces, which adjustments are indicated by a fourth visual display.
3. An amplified stethoscope comprising a first microphone disposed on a first side of a pickup head, such first side placed upon and at times moved about a patient, and a second microphone disposed on a second side of the pickup head in such a manner as to be exposed to ambient noise, the first microphone providing a first microphone signal comprising (a) a desirable signal component corresponding to detected anatomical sounds emanating from within such patient, (b) an undesirable signal component corresponding to pickup head movement artifact noises resulting from movement of the pickup head about the patient, and (c) an undesirable signal component corresponding to competing external ambient noises, and the second microphone providing a second microphone signal also comprising an undesirable signal component corresponding to competing external ambient noises, wherein the first microphone signal is applied as a first input and the second microphone signal is applied as a second input to a signal processor providing a processed signal, the processed signal is applied as input to at least one amplifier providing at least one amplified signal, and the at least one amplified signal is applied to at least one transducer comprised in at least one earpiece, wherein the signal processor applies to the first microphone signal at least one function of; a first signal process of a squelch function that assumes an active state, by at least one of disabling and attenuating the processed signal, during at least one of (a) an artifact noise component in the first microphone signal above a first amplitude threshold, and (b) an increasing rate of change in amplitude of such artifact noise component above a first rate of change threshold; a second signal process of a low pass filter function having at least two processor- selectable upper cut-off frequencies; a third signal process in which a decrementing of the processor-selectable upper cut-off frequency occurs during at least one of (a) an ambient noise component in the second microphone signal above a second amplitude threshold, and (b) an increasing rate of change in such ambient noise component above a second rate of change threshold, and further in which an incrementing of the processor-selectable upper cut-off frequency occurs during at least one of (c) an absence of an ambient noise component in the second microphone signal above such second amplitude threshold, and (d) a decreasing rate of change in such ambient noise above such second rate of change threshold; a fourth signal process in which an active squelch state, in accordance with the first signal process, defaults after a first predetermined time period to an immediately previous squelch inactive state; a fifth signal process in which a low region upper cut-off frequency, in accordance with the third signal process, defaults after a second predetermined time period to an immediately previous high region upper cut-off frequency state; a sixth signal process comprising at least one of limiting and compressing the first microphone signal; a seventh signal process of a high pass filter having a cut-off frequency lying between substantially 20 Hz and substantially 100 Hz; an eighth signal process of at least one selectable frequency response equalization curve, and a binaural summation control whereby the processor signal is applied with controllable amplitude ratio adjustments to left and right amplifiers operating left and right transducers and earpieces.
4. An amplified stethoscope comprising a first microphone disposed on a first side of a pickup head, such first side placed upon and at times moved about a patient, and a second microphone disposed on a second side of the pickup head in such a manner as to be exposed to ambient noise, the first microphone providing a first microphone signal comprising (a) a desirable signal component corresponding to detected anatomical sounds emanating from within such patient, (b) an undesirable signal component corresponding to pickup head movement artifact noises resulting from movement of the pickup head about the patient, and (c) an undesirable signal component corresponding to competing external ambient noises, and the second microphone providing a second microphone signal also comprising an undesirable signal component corresponding to competing external ambient noises, wherein the first microphone signal is applied as a first input and the second microphone signal is applied as a second input to a signal processor providing a processed signal, the processed signal is applied as input to at least one amplifier providing at least one amplified signal, and the at least one amplified signal is applied to at least one transducer comprised in at least one earpiece, wherein the signal processor applies to the first microphone signal at least one function of; a first signal process of a squelch function that assumes an active state, by at least one of disabling and attenuating the processed signal, during at least one of (a) an artifact noise component in the first microphone signal above a first amplitude threshold, and (b) an increasing rate of change in amplitude of such artifact noise component above a first rate of change threshold, and wherein such active state is indicated by a first visual display; a second signal process of a low pass filter function having at least two processor- selectable upper cut-off frequencies, the first such frequency lying in a low region between substantially 500 Hz and substantially 1 ,500 Hz, and the second such frequency lying in a high region between substantially 1,500 Hz and substantially 5,000 Hz; a third signal process in which a decrementing of the processor-selectable upper cut-off frequency occurs during at least one of (a) an ambient noise component in the second microphone signal above a second amplitude threshold, and (b) an increasing rate of change in such ambient noise component above a second rate of change threshold, and further in which an incrementing of the processor-selectable upper cut-off frequency occurs during at least one of (c) an absence of an ambient noise component in the second microphone signal above such second amplitude threshold, and (d) a decreasing rate of change in such ambient noise component above such second rate of change threshold, and wherein at least one of a low region and a high region selectable upper cut-off frequency is indicated by a second visual display; a fourth signal process in which an active squelch state, in accordance with the first signal process, defaults after a first predetermined time period to an immediately previous squelch inactive state; a fifth signal process in which a low region upper cut-off frequency, in accordance with the third signal process, defaults after a second predetermined time period to an immediately previous high region upper cut-off frequency state; a sixth signal process comprising at least one of limiting and compressing the first microphone signal; a seventh signal process of a high pass filter having a cut-off frequency lying between substantially 20 Hz and substantially 100 Hz; an eighth signal process of at least one selectable frequency response equalization curve, which frequency responses are indicated by a third visual display, and a binaural summation control whereby the processor signal is applied with controllable amplitude ratio adjustments to left and right amplifiers operating left and right transducers and earpieces, which adjustments are indicated by a fourth visual display.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US81422606P | 2006-06-17 | 2006-06-17 | |
| US60/814,226 | 2006-06-17 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2007149279A2 true WO2007149279A2 (en) | 2007-12-27 |
| WO2007149279A3 WO2007149279A3 (en) | 2008-03-06 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US2007/013865 WO2007149279A2 (en) | 2006-06-17 | 2007-06-13 | Amplified stethoscope with automatic noise reduction signal processing |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2007149279A2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11357471B2 (en) | 2006-03-23 | 2022-06-14 | Michael E. Sabatino | Acquiring and processing acoustic energy emitted by at least one organ in a biological system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5492129A (en) * | 1993-12-03 | 1996-02-20 | Greenberger; Hal | Noise-reducing stethoscope |
| US6999592B2 (en) * | 2002-08-08 | 2006-02-14 | Chelen William E | Time and frequency windowed pocket cardiac stethoscope |
-
2007
- 2007-06-13 WO PCT/US2007/013865 patent/WO2007149279A2/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5492129A (en) * | 1993-12-03 | 1996-02-20 | Greenberger; Hal | Noise-reducing stethoscope |
| US6999592B2 (en) * | 2002-08-08 | 2006-02-14 | Chelen William E | Time and frequency windowed pocket cardiac stethoscope |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11357471B2 (en) | 2006-03-23 | 2022-06-14 | Michael E. Sabatino | Acquiring and processing acoustic energy emitted by at least one organ in a biological system |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2007149279A3 (en) | 2008-03-06 |
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