Showing papers on "Microphone published in 1983"

Radio transmitter and receiver device having a headset with speaker and microphone

Abstract: A radio transmitter and receiver device in which a head band has a transmitting microphone at one end and a receiving speaker at the other end. This microphone comprises a bone transmission type microphone for detecting aural oscillation of an external auditory canal transmitted through a bone tissue of a head portion from a mouth, said microphone being brought into contact with a side head portion at the rear of an ear. Thus, one ear is blocked by the speaker but the other ear is open, and therefore, a user can catch noises thereabout. A transmitting and receiving antenna has matching means and is mounted on the side of the speaker.

Microphone array apparatus and method for extracting desired signal

Abstract: An acoustic signal is received by a plurality of microphone elements and their outputs are delayed by delay means and weighted and summed up by weighted summation means, obtaining a noise-reduced output. A fictitious desired signal is electrically generated and the weighting values of the weighted summation means is determined based on the fictitious desired signal and the outputs of the microphone elements when receiving substantially only noises.

A voice-actuated switching system

Abstract: A voice-actuated switching system selectively connects multiple microphones to an audio line in accordance with the output signal levels from each of the microphones. The state of each microphone is determined by its use and can exit in one of three states: selected, mixed, or off. The microphone with the greatest output signal level at any given time is considered in the selected state and is selected for connecting to the audio line with no loss. Those microphones in the mixed state have their output signal levels attenuated before being connected to the audio line. And those microphones in the off state have their outputs essentially disconnected from the audio line. The user of a microphone while in the mixed state can be heard along with the user of a microphone while in the selected state although at a lower level. Improved accuracy is obtained in the microphone selection process by comparing the microphone signals to each other and to a reference level that takes into account any offsets induced into the signals by the system. The system can accommodate any number of microphones.

Wind/breath screen for a microphone

Abstract: An effective wind/breath screen for a microphone is described. The wind/breath screen includes a rigid perforated structure for enclosing the microphone. The microphone being physically isolated from the rigid perforated structure by a surrounding pad of air therebetween. A porous layer is utilized to enclose the rigid perforated structure thereby creating a pad of dead air between the microphone and the porous layer, whereby the speech signal reaches the microphone without substantial attenuation, and the wind/breath noise is suppressed. The present wind screen for a microphone is optimized for, and is particularly effective for voice data entry applications.

Hearing aid responsive to signals inside and outside of the audio frequency range

Abstract: A hearing aid having a microphone (10), a microcomputer (12) for digital signal processing of digitized microphone signals and an electroacoustic converter (14) for acoustic reproduction of the processed digitized signals, is equipped with at least one further sensor (16, 18) responsive to signals outside the acoustical range of audibility. These further sensor signals are processed according to a different program stored in a second memory (19) and supplied as additional data via an output (B2) of the microcomputer (12) preferably to the electro-acoustical converter (14). As a result, data such as the signals of a traffic light transmitter, signals from a paging system, or signals announcing a telephone call, door bell or the like, can be superimposed on the normal auditory functions. By appropriately coordinate signal trains, for example generated in accordance with the program stored in the second memory, a hearing-impaired person can easily distinguish among these additional functions.

Microphone shock-mounting apparatus

Abstract: A shock-mounting apparatus designed for receiving and holding a microphone so as to isolate the microphone from surrounding structure-borne environmental vibration. The apparatus comprises a cradle that flexes when opening to receive the microphone and then closes firmly around the microphone body to hold it in place. The cradle also permits the microphone to be received into and removed from the shock-mounting apparatus without requiring disconnection from the signal output cable.

Modelling and enhancement of reverberant speech using an envelope convolution method

Abstract: Acoustic environments can be treated as linear systems whose transmission properties are given by their impulse response functions. This basic model can be extended, under certain conditions, to describe the relationship between the envelopes of the input and output waveforms. Such a model is proposed in the context of a multiband processing scheme, aiming at the enhancement of single microphone recorded reverberant speech signals. The specific requirements of this model permit a simplified approach to the estimation of the envelope functions. The model allows accurate evaluation of the envelope of the reverberant speech, even when little prior information about the room characteristics is available. Speech enhancement can be then achieved after envelope deconvolution in each band, which recovers the envelope of the anechoic signal from the measured speech envelope, and final reconstruction of the speech waveform using the original phase function.

Pickup device for picking up vibration transmitted through bones

Abstract: A pickup device for picking up sound generated by the vocal chords and transmitted through bones from the nasal bone. A microphone (11) is mounted on or embedded into an eyeglass-like assembly (13, 15). When the microphone is mounted as a nosepiece, it is made into direct contact with the nose so that it directly picks up vibration transmitted through the nasal bone. When the microphone is mounted on the eyeglass-like frame or embedded therein, it picks up vibration transmitted through the nosepieces and eyeglass-like frame. A cord (12) whose one end is electrically connected to the microphone is held by holding member extended from the eyeglass-like assembly (13, 15) so that the transmission of mechanical vibration to the microphone is prevented.

Phased-array sound pickup apparatus having no unwanted response pattern

Abstract: In a phased-array sound pickup apparatus microphones are divided into a first and second subarrays, the microphones of the first subarray having individual unidirectional response patterns oriented on one side of the normal to the array and the microphones of the second subarray having their response patterns oriented on the other side of the normal so that the array's main lobe assumes different orientation from the orientation of the microphone's individual response patterns so that the array's unwanted back lobe falls outside of the microphone's response patterns. The microphones may be grouped into a plurality of pairs and the signals from the paired microphones are mixed so that different individual response patterns are generated in correlation with the array's main front lobe to cause the unwanted back lobe to occur outside of the individual response patterns.

Resonant peak control

Abstract: A hearing aid having a microphone, an amplifier and a receiver for delivering the amplified sound to a user's ear, in which an adjustable resonant peak control is used to shift the frequency response of the amplifier to a lower frequency range in order to reduce feedback without substantial reduction in high frequency amplification or saturation levels

Acceleration vibration detector

Abstract: An ear microphone for an external auditory canal insertion type two-way communication earpiece. Within the casing (4) of the earpiece a fixed electrode (9) and a vibrating electrode (6) are positioned in capacitive relation with each other, the vibrating electrode (6) for detecting acceleration vibration from outside the casing (4) in the form of bone-conducted voice sound vibration within the external auditory canal. Electrical signals transduced from picked-up voice sounds pass through an impedance conversion circuit (11) mounted in the ear microphone.

Sound transfer from a hearing aid to the human ear drum

Abstract: An improved in-the-ear hearing aid. The earmold is divided into two separate chambers defined by a divider wall. A first chamber has an opening adjacent the outer ear and the second chamber has an opening adjacent the ear drum. A microphone is positioned adjacent the first chamber opening. An amplifier and a battery for its power source are located within the first chamber. A receiver with a sound emitting aperture is located within the second chamber. The sound emitting aperture is directed toward the divider wall. The receiver is completely surrounded by an acoustic resistance material which separates the receiver from the walls of the chamber. The microphone, amplifier, battery and receiver are electrically interconnected for supplying to the receiver amplified microphone signals. The combination of the dimensions of the chamber and the acoustic material provide a horn effect to the receiver produced sound. The opening of the second chamber may be covered with a removable grill.

Conference telephone set

Abstract: PURPOSE: To obtain an optimum talking correspondence characteristics without howling and receiving blocking by providing a microphone, a speaker and a voice switch circuit or the like, operating and processing a transmission/receiving signal level and comparing the level so as to control the loss of a variable loss circuit at talking. CONSTITUTION: An analog transmission signal from the microphone 7 is amplified, analog/digital-converted 5, fetched to a control circuit 2, the receiving signal from the receiving line terminal 11 is also amplified 13, analog/digital-converted 6 and fetched to the circut 2. Further, the circuit 2 compares the level of both data and operates them so as to control variable loss circuits 3 and 4. As a result, a voice signal of the microphone 7 prsses through the circuit 3 with no loss, is amplified 9 and transmitted from a transmission line terminal 10. On the other hand, the amplified receiving signal is subject to processing of vairable loss so as not to cause hawling by the circuit 4, amplified 14 and applied to the speaker 15. Then, noise is sounded 15 from a noise sounding circuit 17 by a manual switch 16, the sound coupling loss and the echo time in the conference room are measured and stored in the circuit 15. COPYRIGHT: (C)1984,JPO&Japio

Hearing aid coupled with a radio

Abstract: A built in radio/hearing aid comprises a control voltage generator means which generates a control voltage depending on the level of a microphone signal of the hearing aid and a mixing control means which controls the ratio of the mixture of a radio signal from a radio signal generator and the microphone signal from a microphone in accordance with the level of the control voltage. Thus, the level of the radio signals is automatically changed in accordance with the level of circumstantial audio signals within the microphone signal.

Studies on the Vibration and Sound of Defective Rolling Bearings : Second Report : Sound of Ball Bearings with One Defect

Abstract: An investigation was undertaken with a view to establishing a procedure for diagnosing defects in rolling bearings from their vibration and sound. In the present investigation the sound of a rolling bearing with one dent in the race surface of the inner or outer ring or in the ball surface was studied. When the inner ring was rotated at a constant speed under a given thrust load applied to the outer ring, the sound occurring in three directions, i.e., radial, 45° and frontal was measured by a condenser microphone. Using the output so obtained, sound waveforms were observed, real time frequency analysis of the sound was done using Fast Fourier Transform analyzer, and the microphone position effects on the sound, etc. were examined. As a result, the fundamental characteristics of the sound of ball bearings having one dent were clarified, and a method by which to locate the defect and determine its size was established.

Magnetic bone conduction and eardrum oscillation microphone in common use of transmission and reception

Abstract: PURPOSE:To attain the reproduction of natural sound and common use of transmission and reception, by picking up high frequency sound of bone conduction and low frequency sound of eardrum oscillation at the same time. CONSTITUTION:A space formed with a main body case 11 and a diaphragm 14 is formed as air-tightness, and an acoustic pipe 23 is fitted. In using the microphone, an outer skin contact chip 16 contacts the surface of a living body and an ear chip 24 is inserted an ear hole. The oscillation of the surface of the living body is delivered to the diaphragm 14 via the chip 16. In this case, since the mechanical impedance of the system including the diaphragm 14 is selected to be matched with the synthetic impedance of the living body, the low frequencies are subject to high attenuation rather than the high frequencies. Further, the bone conduction sound includes much high frequency compoents. The sound of the eardrum having low frequency components passes through the pipe 23 and reaches the diaphragm 14. Thus, the oscillation of high and low frequencies is delivered to the diaphragm 14. In case using the microphone as a transmitter, a moving coil 17 oscillates the diaphragm 14 with electric signals and the sound is delivered to the pipe 23 and the eardrum. Further, it is delivered to the surface of the living body via the chip 16.

Anti-blocking device including stuck microphone reliever for aircraft voice communication system

Abstract: Systems for preventing channel blockage on aircraft voice communication frequencies caused either by a pilot beginning a transmission while someone else is transmitting on the same channel (i.e., "stepping on" or "blocking" the first transmission), or by a "stuck microphone" condition resulting from undesired activation of the microphone switch circuit. In accordance with the invention, a "step-off" device (SOD) and a "stuck microphone reliever" (SMR) are combined in a single device, termed an "anti-blocking device" (ABD). The entire device may be provided in retrofit form and draws all its operating power from the radio push-to-talk switch line, with no internal modification to the radio required. The step-off device portion of the anti-blocking device senses when a selected radio frequency is in use, and when in use, prevents transmission even when the microphone switch circuit is operated. The stuck microphone reliever includes a transmitter-disabling means connected to the microphone switch circuit for limiting any transmission to a predetermined duration even though the microphone switch circuit is activated for a longer duration.

Microphone pickup for musical instruments

Abstract: An audio pickup for musical instruments employing a condenser-type microphone mounted on a suction cup which is pressed against the sounding board or the like of the instrument.

Public address system

Abstract: A central station (10) is linked to a plurality of loudspeaker stations (11) by a common digital and audio highway (12). Each loudspeaker station has a unique address (22) and digital signals are addressed to the loudspeaker stations to turn the loudspeakers (13) on and off and establish the loudness levels by way of variable gain amplifiers (14). Each loudspeaker station (11) includes digital circuitry centered on a microprocessor (17) for responding to address and control words from the central station (10) and controlling the amplifier (14). To test whether a loudspeaker is speaking, an adjacent microphone (24) can return an answering signal to the digital highway by way of an amplifier (26) and analog input port (25). In a modified embodiment the answering signal is sent on the audio highway and the amplifier (14) is energised for test purposes by a tone generator controlled by the digital circuitry.

Improvements relating to active acoustic attenuators

Abstract: A speaker 17 is connected by a waveguide 19 to an acoustic mixer 15 leading from a duct 13 carrying source sounds to be cancelled by an active acoustic attenuator 11. The coupling component which couples the physical system with the electronic system 11, consists of a microphone array 33 disposed in the duct 13, and a microphone 35 disposed in acoustic mixer 15 downstream from the waveguide 19. Broad band noise is sensed by microphone array 33 which produces a signal which causes an adaptive filter 23 to drive the speaker 17 so as to introduce "cancelling" noise. The microphone 35 senses the degree of cancellation of the source sound by the speaker 17. The signal from microphone 35 produces an error signal, which is also sent to the adaptive filter to adjust its output so as to produce a more effective "cancelling" sound from the speaker 17.

Portable news-gathering cassette recorder having microphone talk-over capability

Abstract: A portable tape recorder for remote location news-gathering including a rugged metal housing having operating controls and input-output connections located at one end for ease of access. An audio output suitable for direct interconnection to telephone circuitry is provided in addition to internal speaker and external headset audio output connections. A talk-over preamp operatively interconnects the microphone or other audio input to the recorder output when the recorder is in the pause mode facilitating the use of the recorder microphone for direct telephone line connection. This permits live reporter commentaries, introductions, or `wrap-arounds` to be conveniently interspersed with pre-recorded news story segments. The speaker audio output is muted in the talk-over mode to preclude acoustic feedback while reporter `side-tone` monitoring is available through the external headset or telephone handset connections.

Shock absorbing transducer module

Abstract: A modular transducer mounting arrangement includes a substantially planar support plate. An aperture having an angular bevel is provided in the support plate such that a loudspeaker may be positioned in the bevel to allow sound to exit from the loudspeaker in a manner which is substantially unobstructed acoustically. An adhesive shock absorbing pad is attached to the rear of the support plate for isolating the loudspeaker microphone and support plate from mechanical shock. This creates a free floating and reliable transducer mounting assembly which provides shock isolation and easy serviceability.

Electronic stethoscope with automatic power shut-off

Abstract: In an electronic stethoscope which includes a pickup head, a microphone, a tubular accoustic connection between the pickup head and microphone, an amplifier receiving an input from the microphone, a speaker coupled to the output of the amplifier, a binaural headpiece and tubes acoustically coupling the output of the speaker to the binaural headpiece, there is included a switch by means of which a momentary on operation can be achieved and a timer responsive to the switch to couple power to amplifier circuit, the timer adapted to shut power off after a predetermined period of time. Preferably the amplifier is an integrated circuit operational amplifier with a filter circuit which brings up lower frequencies interposed between the amplifier and speaker.

Performance characteristics for hearing aid microphone versus telephone and telephone/telecoil reception modes.

Abstract: Two hearing aids and three telephone receivers were used to compare electroacoustic and word intelligibility data for hearing aid microphone reception versus telephone/telephone and telephone/telec...

Sound detecting device

Abstract: A sound detecting device for amplifying distant or weak sounds, including a novel loud sound suppressing circuit for temporarily shunting the amplifier input signal to ground whenever the amplifier output signal exceeds a predetermined amplitude. The microphone, amplifier, and sound suppressing circuit are mounted in a wand shaped much like a flashlight. The wand can be attached to headphones.

Foil electret transducer for blood pressure monitoring.

Abstract: A foil electret microphone for use under the cuff of an automatic blood pressure monitoring system is described. The transducer is designed to operate with relatively flat sensitivity over a static pressure range of 40 to 250 mm Hg (5.33×104 to 3.33×105 dyn/cm2). The new electret microphone differs from conventional microphones used for airborne sound reception in two ways: (1) the diaphragm thickness is 50 μm rather than the typical 12.5 or 25 μm, and (2) the backplate contains a set of annular ridges spaced at 4 mm rather than the typical 7–10 mm. This microphone offers three advantages over the piezoelectric microphone now in use: (1) greater tolerance in positioning the microphone over the brachial artery, (2) nearly 20‐dB higher sensitivity and signal‐to‐noise ratio, and (3) the ability to obtain measurements with the microphone placed midway between the elbow and shoulder. Tests of the new foil electret microphone in conjunction with the automatic blood pressure monitoring system indicate that the automatic and conventional measurements of systolic and diastolic blood pressure agree to within 5 mm Hg at least 90% of the time. In addition, the electret microphone is able to obtain automatic measurements on subjects with a wider range of ages and sizes.