Multi-frequency transmission system for implanted hearing aids
First Claim
1. A multi-frequency transmission system of an implanted hearing aid, comprisingmeans for converting an acoustic signal in an electric signal;
- a plurality of band pass filters connected to said converting means for filtering different frequency bands in audio frequency range;
a plurality of high frequency transmitters each transmitting an amplitude modulated high frequency carrier signal;
a speech processor including a plurality of threshold switching means connected respectively between said band pass filters and inputs of said high frequency transmitters, said threshold switching means having adjustable threshold levels;
a bipolar transmitting stage including two additional high frequency transmitters connected to said speech processor to generate alternating high frequency pulses of the same length but of different polarity;
said high frequency transmitters and said additional high frequency transmitters being connected via an end stage to a common transmitting coil;
a channel selector connected between said high frequency transmitters and said threshold switching means to trigger simultaneously one of said high frequency transmitters and one of said additional high frequency transmitters in said bipolar transmitting stage; and
receiving means implanted in user'"'"'s body, said receiving means including a single high frequency input channel and a plurality of excitation electrodes responsive to different frequencies of the received signal.
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Accused Products
Abstract
A multi-frequency transmission system for implanted hearing aid includes an external transmitting part and an encapsuled receiver part implantable into middle ear of the user. The transmitting part includes a microphone, a speech processor including a set of audio frequency band pass filters connected respectively via adjustable threshold switches to pulse shapers which release an audio frequency band only when an adjusted threshold level is exceeded. A plurality of high frequency transmitters is modulated by the signals from the pulse shapers. A pair of additional high frequency transmitters is controlled by the pulses from the speech processor to alternately transmit high frequency pulses corresponding to the polarity of the triggering pulses. A frequency channel selector is connected between the transmitters and the speech processor to activate simultaneously one of the transmitters from the bipolar high frequency stage and one of the amplitude modulated transmitters. The combined signal is applied to a transmitting coil and received by a receiver unit implanted in user'"'"'s ear. The receiver includes a plurality of resonant circuits assigned to respective high frequency transmitters and a pair of switching transistors of opposite type of conductivity which are power supplied by a portion of a rectified high frequency signal and control the polarity of the excitation signal applied to the implanted electrodes.
132 Citations
8 Claims
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1. A multi-frequency transmission system of an implanted hearing aid, comprising
means for converting an acoustic signal in an electric signal; -
a plurality of band pass filters connected to said converting means for filtering different frequency bands in audio frequency range; a plurality of high frequency transmitters each transmitting an amplitude modulated high frequency carrier signal; a speech processor including a plurality of threshold switching means connected respectively between said band pass filters and inputs of said high frequency transmitters, said threshold switching means having adjustable threshold levels; a bipolar transmitting stage including two additional high frequency transmitters connected to said speech processor to generate alternating high frequency pulses of the same length but of different polarity;
said high frequency transmitters and said additional high frequency transmitters being connected via an end stage to a common transmitting coil;a channel selector connected between said high frequency transmitters and said threshold switching means to trigger simultaneously one of said high frequency transmitters and one of said additional high frequency transmitters in said bipolar transmitting stage; and receiving means implanted in user'"'"'s body, said receiving means including a single high frequency input channel and a plurality of excitation electrodes responsive to different frequencies of the received signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification