Patents
Sitemap › H04 - Electric communication technique › H04R - Loudspeakers, microphones, gramophone pick-ups or like acoustic electromechanical transducers; Deaf-aid sets; Public address systems › H04R 3 - Circuits for transducers
Patents for H04R 3 - Circuits for transducers (18,190)
11/1989
11/14/1989US4881123 Voice override and amplitude control circuit
11/08/1989EP0340974A2 Active acoustic attenuation system with differential filtering
11/08/1989EP0340762A2 Impedance compensation circuit in a speaker driving system
11/08/1989EP0340516A1 Speakerphone using digitally compressed audio to detect acoustic feedback
11/08/1989EP0340435A2 Acoustic apparatus
11/02/1989EP0339819A2 Electronic filter
11/02/1989EP0339470A2 Electroacoustic driving circuit
10/1989
10/24/1989US4876499 Differental voltage controlled exponential current source
10/24/1989US4876459 Toggling speakerswitch
10/11/1989EP0336303A2 Acoustic apparatus
10/10/1989US4873722 Multi-channel reproducing system
10/05/1989WO1989009465A1 Electro-acoustical system
10/04/1989EP0335468A1 Electro-acoustical system
10/04/1989EP0335153A2 Audio-visual radiation source
09/1989
09/27/1989EP0334238A2 Acoustic Apparatus
09/27/1989EP0334217A2 Method and apparatus of expanding acoustic reproduction range
09/26/1989US4870690 Audio signal transmission system
09/20/1989EP0333552A1 Sonde, device for image formation with such a sonde and method for using the device
09/20/1989EP0333461A2 Active acoustic attenuation system for higher order mode non-uniform sound field in a duct
09/20/1989EP0333411A2 Headphone assemblies
09/19/1989US4868878 Sound field correction system
09/19/1989US4868870 Servo-controlled amplifier and method for compensating for transducer nonlinearities
09/19/1989US4868401 Method and means for measuring distance of a moving object from a fixed point of reference
09/19/1989CA1259663A1 Noise canceling system
09/13/1989EP0332053A2 Acoustic apparatus
09/05/1989US4864627 Microphone mixer with gain limiting and proportional limiting
09/05/1989US4864624 Piezoelectric loudspeaker with thermal protection
09/05/1989US4864547 Regulated ultrasonic generator
08/1989
08/30/1989EP0330062A1 Radio receiver for a vehicle
08/29/1989US4862278 Video camera microphone with zoom variable acoustic focus
08/24/1989WO1989007860A1 Radio receiver for vehicles
08/23/1989EP0126420B1 A speech recognition system
08/22/1989US4860370 Magnetically suspended acoustical speaker
08/22/1989US4860366 Teleconference system using expanders for emphasizing a desired signal with respect to undesired signals
08/22/1989US4860365 Method of fractionating the sound restoration of modulated signals in parallel mounted transducers, and sets of corresponding transducers
08/16/1989EP0327617A1 Improvements relating to noise reduction systems
08/15/1989CA1258517A1 Noise rejection in a sonic transducer
08/09/1989EP0321455A4 Emulated guitar loudspeaker.
08/08/1989US4856065 Power fader for a loudspeaker system
07/1989
07/20/1989DE3800222A1 Microphone protected against acoustic feedback
07/13/1989DE3744501A1 Transceiver
07/05/1989EP0322686A2 Acoustic apparatus
07/05/1989EP0322679A2 Acoustic apparatus
07/04/1989US4845775 Loudspeaker reproduction apparatus in vehicle
07/04/1989US4845758 Equalizer with adjustable band filters and a digital filter suitable for use in the equalizer
06/1989
06/28/1989EP0321455A1 Emulated guitar loudspeaker.
06/27/1989US4843625 Sound reproduction systems
06/27/1989US4843621 Speakerphone using digitally compressed audio to detect acoustic feedback
06/20/1989CA1256036A1 Microphone actuation control system suitable for teleconference systems
06/15/1989DE3740643A1 Bass speaker system
06/06/1989US4837834 Active acoustic attenuation system with differential filtering
06/06/1989US4837829 Acoustic sound system for a room
06/01/1989DE3839070A1 Lautsprechersystem Speaker system
05/1989
05/24/1989DE3737873A1 Method and device for improving the intelligibility of voice in communications devices
05/24/1989CN2038304U Transmitter-receiver with good tone quality connected externally to a radio telephone
05/23/1989US4833719 Method and apparatus for attentuating external origin noise reaching the eardrum, and for improving intelligibility of electro-acoustic communications
05/18/1989WO1989004580A1 Microphone provided with earphone
05/09/1989US4829571 Headphone
05/09/1989US4829500 Portable wireless sound reproduction system
05/09/1989US4829270 Compansion system
05/03/1989DE3816170C1 Frequency switch
05/02/1989US4827458 Sound surge detector for alerting headphone users
04/1989
04/19/1989EP0312144A2 High voltage pulse power driver
04/19/1989EP0162858B1 Acoustic direction identification system
04/18/1989US4823392 Controlling the dynamic range of audio signals
04/18/1989US4821706 High voltage pulse power drive
04/13/1989DE3733132A1 Circuit arrangement for acoustic compensation of the ambient noise in the case of headphone (earphone) reception
04/12/1989EP0310621A1 Aircraft cabin noise control apparatus
04/11/1989US4821328 Sound reproducing system with Hall effect motional feedback
04/11/1989US4821323 Stereo headphone
04/06/1989DE3731366A1 Television receiver with a bass loudspeaker enclosure
04/05/1989EP0309835A2 Motional load driver
03/1989
03/28/1989US4817168 Directional microphone
03/28/1989US4817160 Amplifier with automatic gain control
03/28/1989US4817153 Method and apparatus for transforming a monaural signal into stereophonic signals
03/28/1989US4817152 Stereo system with piezo-electrical film speaker
03/28/1989US4816743 Measuring method
03/22/1989EP0308009A1 Method of and arrangement for adjusting the transfer characteristic to two listening positions in a space
03/22/1989EP0307685A1 Servo-control method for the operating frequency of a sonic horn
03/21/1989US4815139 Active acoustic attenuation system for higher order mode non-uniform sound field in a duct
03/21/1989US4815047 Synthetic focus annular array transducer
03/21/1989US4815043 Ultrasonic imaging apparatus
03/16/1989DE3822353A1 Hands-free system
03/14/1989US4811740 Ultrasonic diagnosis apparatus capable of probe exchange
03/09/1989DE3728571A1 Loudspeaker unit
03/09/1989DE3728481A1 Optical transmission system
03/09/1989DE3728425A1 Loudspeaker box having an emission characteristic which is positively matched to the method of operation
03/08/1989EP0306288A2 Ultrasonic imaging apparatus
03/07/1989US4811309 Microphone probe for acoustic measurement in turbulent flow
03/01/1989EP0305208A2 Automated stereo synthesizer and generating method for audiovisual programs
02/1989
02/28/1989US4808948 Automatic tuning system for ultrasonic generators
02/23/1989DE3727098A1 Bass loudspeaker enclosure
02/22/1989EP0304257A2 Voice enhancer system
02/22/1989EP0303912A2 Woofer-loudspeaker box
02/21/1989US4807217 Multi-channel stereo reproducing apparatus
02/21/1989US4807051 Image pick-up apparatus with sound recording function
02/21/1989US4805728 For a musical performer
02/14/1989US4805221 Construction of sound converter in sound guide, especially for loudspeakers, for example speaker boxes
01/1989
01/31/1989US4802227 Noise reduction processing arrangement for microphone arrays
01/31/1989US4801838 Method and device for improving the sensitivity and the signal to noise ratio of piezo-electric transducers having a plurality of sensors combined in parallel
1 ... 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182