Stethoscopic system for high-noise environments

• US 5,497,426 A
• Filed: 11/15/1993
• Issued: 03/05/1996
• Est. Priority Date: 11/15/1993
• Status: Expired due to Fees

• Current Assignee: Gregory Jay
• Original Assignee: Gregory Jay
• Inventors: Jay, Gregory D.
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US08/153,413
• Time in Patent Office: 841 Days
• Field of Search: 381/71, 381/72, 381/67
• US Class Current: 381/67
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R

Abstract

An electronic stethoscopic system is described which permits detection of auscultory sounds in a patient in high noise environments such as ambulances and aircraft. The stethoscope employs an electroacoustical transducer, an acoustical driver mounted in a headset providing acoustical isolation from exterior noise, a summing microphone positioned within the insulating headset, and active noise reduction circuitry to feed an error signal back from the summing microphone to the acoustical driver so as to effectively cancel the unwanted acoustical noise originating external to the insulating headset. The stethoscopic system includes circuitry permitting the headset to selectively receive the audio output from a vehicular intercom system whenever a voice signal is present, thereby allowing treating medical personnel to monitor the patient while participating in the conversation being conducted on the vehicle'"'"'s intercom system.

Claims

1. A stethoscopic system for use in high-noise environments, comprising:

transducer means for converting body sounds into an electrical output signal;

driver means for converting the electrical output signal of the transducer means into an acoustical pressure signal;

a summing microphone;

an active noise reduction circuit having an input signal received from the transducer means, an output signal transmitted to the driver means, signal received from the summing microphone;

a headset having an input signal, said headset providing an enclosure for the driver means and the summing microphone and forming a close-fitting acoustical seal with a listener'"'"'s head at points on the listener'"'"'s skull surrounding the ear so as to substantially attenuate acoustical noise originating external to the headset;

switch means for selecting either the electrical output signal from the transducer means or a voice signal from a vehicular intercom system as the input signal to the headset;

means for causing the switch means to select said voice signal as the input signal to the headset when said voice signal is present; and

an amplifier electrically coupled between the transducer means and the switch means, said amplifier having a positive gain of at least 2000 substantially throughout the audio frequency range of cardiac and pulmonary auscultory sounds.

2. A stethoscopic system for use in high-noise environments, comprising:

transducer means for converting body sounds into an electrical output signal;

driver means for converting the electrical output signal of the transducer means into an acoustical pressure signal;

a summing microphone;

an active noise reduction circuit having an input signal received from the transducer means, an output signal transmitted to the driver means, and a feedback signal received from the summing microphone;

means for mounting the driver means and the summing microphone near a listener'"'"'s ear;

switch means for selecting either the electrical output signal from the transducer means or a voice signal from a vehicular intercom system as the input signal to the active noise reduction circuit;

means for causing the switch means to select said voice signal as the input signal to the active noise reduction circuit when said voice signal is present; and

an amplifier electrically coupled between the transducer means and the switch means, said amplifier having a positive gain of at least 2000 substantially throughout the audio frequency range of cardiac and pulmonary auscultory sounds.

3. A stethoscopic system for use in high-noise environments, comprising:

transducer means for converting body sounds into an electrical output signal;

driver means for converting the electrical output signal of the transducer means into an acoustical pressure signal;

a summing microphone for converting the ambient noise into an electrical error signal;

means for inversely feeding back the electrical error signal from the summing microphone to said driver means so as to substantially cancel the unwanted acoustical signal originating outside the headset;

a headset having an input signal, said headset providing an enclosure for the driver means and the summing microphone and forming an acoustical seal around a listener'"'"'s ear so as to substantially attenuate acoustical noise originating external to the headset;

means for automatically switching the input signal to the headset from the electrical output signal of the transducer means to a voice signal of a vehicular intercom system when said voice signal is present; and

an amplifier electrically coupled between the transducer means and the automatic switching means, said amplifier having a positive gain of at least 2000 substantially throughout the audio frequency range of cardiac and pulmonary auscultory sounds.