Modulation in a contact hearing system
In one embodiment, the present invention is directed to a contact hearing system comprising: an ear tip including a transmit coil, wherein the transmit coil is connected to an audio processor, including an H Bridge circuit; a first input to the H Bridge circuit comprising an AND circuit wherein a first input to the AND circuit comprises a carrier signal and a second input to the AND circuit comprises an output of a delta sigma modulation circuit, wherein the delta sigma modulation circuit is a component of the audio processor; and a second input to the H Bridge circuit comprising an NAND circuit wherein a first input to the NAND circuit comprises a carrier signal and a second input to the NAND circuit comprises an output of the delta sigma modulation circuit.
1. A contact hearing system comprising:
an ear tip comprising a transmit coil, wherein the transmit coil is connected to an audio processor, comprising an H Bridge circuit;
a first input to the H Bridge circuit comprising an AND circuit wherein a first input to the AND circuit comprises a carrier signal and a second input to the AND circuit comprises an output of a delta sigma modulation circuit, wherein the delta sigma modulation circuit is a component of the audio processor; and
a second input to the H Bridge circuit comprising an NAND circuit wherein a first input to the NAND circuit comprises a carrier signal and a second input to the NAND circuit comprises an output of the delta sigma modulation circuit.
2. A contact hearing system according to claim 1 , wherein an output of a first side of the H Bridge circuit is connected to a first side of the transmit coil and an output of a second side of the H Bridge circuit is connected to a second side of the transmit coil.
3. A contact hearing system according to claim 1 , wherein a capacitor is connected between at least one output of the H Bridge circuit and the transmit coil.
4. A contact hearing system according to claim 1 , wherein the transmit coil is inductively coupled to a receive coil.
5. A contact hearing system according to claim 4 , wherein the receive coil is positioned on a contact hearing device.
6. A contact hearing system according to claim 5 , wherein the contact hearing device comprises a diode detector connected to an output of the receive coil.
7. A method of transmitting signals between a transmitter and receiver in an inductively coupled contact hearing system, the method comprising the steps of:
mixing an output of a delta sigma modulation circuit with a carrier signal using an AND gate;
providing an output of the AND gate to a first input of an H Bridge circuit;
mixing the output of the delta sigma modulation circuit with the carrier signal using an NAND gate;
providing an output of the NAND gate to a second input of the H Bridge circuit;
providing an output of a first side of the H Bridge circuit to a first side of a transmit coil; and
providing an output of a second side of the H Bridge circuit to a second side of the transmit coil.
8. The method of claim 7 further comprising the steps of:
receiving a signal generated by the transmit coil at a receive coil;
passing the received signal through a diode detector.
9. The method of claim 8 further comprising the steps of:
passing the output of the diode detector to a balanced armature transducer.
10. The method of claim 7 wherein the carrier is AM modulated.
11. The method of claim 10 wherein the diode detector demodulates the AM modulated carrier.
12. A contact hearing system comprising:
an ear tip comprising a transmit coil, wherein the transmit coil is connected to an audio processor, comprising an H Bridge circuit, wherein the transmit coil is connected to the output of the H Bridge circuit;
a first input to the H Bridge circuit comprising an AND circuit wherein a first input to the AND circuit comprises a carrier signal and a second input to the AND circuit comprises an output of a delta sigma modulation circuit, wherein the delta sigma modulation circuit is a component of the audio processor; and
a second input to the H Bridge circuit comprising the carrier signal.
13. A contact hearing system according to claim 12 , wherein the second input is an inverted carrier signal.
14. A contact hearing system according to claim 12 , wherein the transmit coil is inductively coupled to a receive coil.
15. A contact hearing system according to claim 14 , wherein the receive coil is positioned on a contact hearing device.
16. A contact hearing system according to claim 15 , wherein the contact hearing device comprises a diode detector connected to an output of the receive coil.
17. A method of transmitting signals between a transmitter and receiver in an inductively coupled contact hearing system, the method comprising the steps of:
mixing the output of a delta sigma modulation circuit with a carrier signal using an AND gate;
providing an output of the AND gate to a first input of an H Bridge circuit;
providing a carrier signal to a second input of an H Bridge circuit;
providing an output of a first side of the H Bridge circuit to a first side of a transmit coil; and
providing an output of a second side of the H Bridge circuit to a second side of a transmit coil.
18. The method of claim 17 further comprising the steps of:
receiving a signal generated by the transmit coil at a receive coil; and
passing the received signal through a diode detector.
19. The method of claim 18 further comprising the steps of:
Passing an output of the diode detector to a balanced armature transducer.
20. The method of claim 19 , wherein the carrier is AM modulated.
21. The method of claim 18 , wherein the diode detector demodulates the AM modulated carrier signal.
22. The method of claim 1 or 12 wherein the Logic, the synchronization of PDM and clock, may be build using a Field Programmable Gate Array (FPGA) and utilizing the low capacitance FPGA output driver to create the H-Bridge.