Automatic Frequency Shift Keying (FSK) tuning circuit for a hearing aid and method
First Claim
1. A frequency-shift-keying (FSK) transceiver for use in a hearing aid, said transceiver having a resonant circuit comprising at least a fixed inductance, a fixed capacitance and a variable capacitance, wherein the transceiver comprises:
- an FSK modulator,a transmitting amplifier,a receiving amplifier, andmeans for controlling the tuning frequency of the resonant circuit to a desired frequency,said tuning means comprising a phase difference detector and a tuning manager,the phase difference detector being adapted for measuring the phase difference across the fixed capacitance,the tuning manager comprisingmeans for receiving symbols from a transmission data buffer,means for receiving measured phase differences from the phase difference detector,means for comparing a first phase difference corresponding to a first, received symbol with a second phase difference corresponding to a second, received symbol andmeans for adjusting the value of the variable capacitance according to the difference between the first phase difference and the second phase difference in order to control the tuning frequency of the resonant circuit.
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Accused Products
Abstract
An frequency shift keying (FSK) transceiver for use in a hearing aid is capable of automatic tuning of the transceiver frequency. The automatic tuning makes use of a phase difference detector and a tuning manager adapted to control the frequency of a resonant circuit of the FSK transceiver according to information received from the phase difference detector. The phase difference detector measures the phase difference across a component of the resonant circuit of the FSK transceiver. If the phase difference of a binary FSK symbol is equal to the phase difference of the opposite binary FSK symbol, the resonant circuit is tuned, otherwise the tuning manager performs a tuning procedure in order to minimize the difference in phase differences, and adjusts the frequency of the resonant circuit accordingly.
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Citations
10 Claims
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1. A frequency-shift-keying (FSK) transceiver for use in a hearing aid, said transceiver having a resonant circuit comprising at least a fixed inductance, a fixed capacitance and a variable capacitance, wherein the transceiver comprises:
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an FSK modulator, a transmitting amplifier, a receiving amplifier, and means for controlling the tuning frequency of the resonant circuit to a desired frequency, said tuning means comprising a phase difference detector and a tuning manager, the phase difference detector being adapted for measuring the phase difference across the fixed capacitance, the tuning manager comprising means for receiving symbols from a transmission data buffer, means for receiving measured phase differences from the phase difference detector, means for comparing a first phase difference corresponding to a first, received symbol with a second phase difference corresponding to a second, received symbol and means for adjusting the value of the variable capacitance according to the difference between the first phase difference and the second phase difference in order to control the tuning frequency of the resonant circuit. - View Dependent Claims (2, 3, 4)
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5. A method for automatic tuning of the frequency of a resonant circuit of a frequency shift keying (FSK) transceiver for a hearing aid, said resonant circuit comprising at least a fixed capacitor, a variable capacitor and an inductance, wherein said method comprises the steps of:
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providing an FSK modulated digital bit stream for the resonant circuit, measuring a first phase difference corresponding to a first, binary symbol across the fixed capacitor, measuring a second phase difference corresponding to a second, binary symbol across the fixed capacitor, comparing the first phase difference to the second phase difference, and controlling the frequency of the resonant circuit by adjusting the value of the variable capacitor when the first phase difference differs from the second phase difference by more than a predetermined amount. - View Dependent Claims (6, 7, 8, 9, 10)
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Specification