Method and apparatus for providing a sidetone in a wireless communication device

• US 7,330,739 B2
• Filed: 03/31/2005
• Issued: 02/12/2008
• Est. Priority Date: 03/31/2005
• Status: Expired due to Fees

• Current Assignee: ST-Ericcson SA (Telefonaktiebolaget LM Ericsson)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Somayajula, Shyam S.
• Primary Examiner(s): Nguyen; Duc M.
• Application Number:
  US11/095,263
• Publication Number:
  US 20060229028A1
• Time in Patent Office: 1,048 Days
• Field of Search: 455/570, 455/569.1, 455/90.1, 455/90.2, 379/388.07, 379/391, 370/201
• US Class Current: 455/570
• CPC Class Codes: H04M 1/6008 in the transmitter circuit
• CPC Class Codes: H04M 1/6016 in the receiver circuit

Abstract

A wireless communication device is disclosed that provides a sidetone to the device user. The device converts an outbound analog audio signal to an outbound audio bitstream from which a sidetone bitstream is extracted. The device also converts an inbound digital audio signal to an inbound audio bitstream. A filter in the device both adds the sidetone bitstream to the inbound audio bitstream and filters the resultant added bitstreams to provide an analog audio signal with sidetone.

Claims

1. A method of operating a wireless communication device comprising:

converting an outbound analog audio signal to an outbound audio bitstream in a first path that includes a transmitter which transmits the outbound audio bitstream;

converting an inbound digital audio signal to an inbound audio bitstream in a second path that includes a receiver which receives the inbound digital audio signal;

extracting a sidetone bitstream from the outbound audio bitstream; and

supplying the inbound audio bitstream and the sidetone bitstream to a filter in the second path, the filter adding the sidetone bitstream to the inbound audio bitstream to produce a resultant signal, the filter also filtering the resultant signal to provide an analog audio signal with sidetone.

2. The method of claim 1, wherein the converting an outbound analog audio signal step comprises converting, by a delta sigma analog to digital converter (ADC), the outbound analog audio signal to the outbound audio bitstream.

3. The method of claim 1, wherein the converting an inbound digital audio signal step comprises converting, by a delta sigma digital to analog converter (DAC), the inbound digital audio signal to the inbound audio bitstream.

4. The method of claim 1, further comprising transmitting, by the transmitter, a pulse code modulation (PCM) representation of the outbound audio bitstream.

5. The method of claim 1 further comprising receiving, by the receiver, the inbound digital audio signal to produce a PCM representation of the inbound digital audio signal.

6. The method of claim 1, wherein the filter comprises a switched capacitor filter.

7. The method of claim 1, wherein the filter comprises a continuous time filter.

8. The method of claim 1, further comprising canceling, by the filter, a DC offset exhibited by the sidetone bitstream.

9. The method of claim 1, further comprising scaling the sidetone bitstream prior to supplying the sidetone bitstream to the filter.

10. The method of claim 1, wherein the wireless communication device includes RF circuitry and digital processing circuitry, the transmitter and receiver being included in the RF circuitry, the method further comprising:

activating the RF circuitry and inactivating the digital processing circuitry, by a controller, during first periods of time; and

inactivating the RF circuitry and activating the digital processing circuitry, by the controller, during second periods of time.

11. A wireless communication device comprising:

a transmitter situated in an outbound path;

a receiver situated in an inbound path;

an analog to digital converter (ADC), situated in the outbound path, that converts an outbound analog audio signal to an outbound audio bitstream that is supplied to the transmitter;

a digital to analog converter (DAC), situated in the inbound path, that converts an inbound digital audio signal, received by the receiver, to an inbound audio bitstream; and

a filter, situated in the inbound path and coupled to the DAC to receive the inbound audio bitstream, the filter being further coupled to the outbound path to receive the outbound audio bitstream, the filter adding the outbound bitstream as a sidetone to the inbound audio bitstream to produce a resultant signal, the filter also filtering the resultant signal to provide an analog audio signal with sidetone.

12. The wireless communication device of claim 11, wherein the ADC comprises a delta sigma ADC.

13. The wireless communication device of claim 11, wherein the DAC comprises a delta sigma DAC.

14. The wireless communication device of claim 11, wherein the filter comprises a switched capacitor filter.

15. The wireless communication device of claim 11, wherein the filter comprises a continuous time filter.

16. The wireless communication device of claim 11, wherein the filter cancels a DC offset exhibited by the outbound audio bitstream that is supplied to the filter as the sidetone.

17. The wireless communication device of claim 11, further comprising:

RF circuitry including the transmitter and receiver;

digital processing circuitry; and

a controller, coupled to the RF circuitry and the digital processing circuitry, that activates the RF circuitry and inactivates the digital processing circuitry during first periods of time, the controller inactivating the RF circuitry and activating the digital processing circuitry during second periods of time.

18. An integrated circuit device comprising:

a transmitter situated in an outbound path;

a receiver situated in an inbound path;

an analog to digital converter (ADC), situated in the outbound path, that converts an outbound analog audio signal to an outbound audio bitstream that is supplied to the transmitter;

a digital to analog converter (DAC), situated in the inbound path, that converts an inbound digital audio signal, received by the receiver, to an inbound audio bitstream; and

a filter, situated in the inbound path and coupled to the DAC to receive the inbound audio bitstream, the filter being further coupled to the outbound path to receive the outbound audio bitstream, the filter adding the outbound bitstream as a sidetone to the inbound audio bitstream to produce a resultant signal, the filter also filtering the resultant signal to provide an analog audio signal with sidetone.

19. The integrated circuit device of claim 18, wherein the ADC comprises a delta sigma ADC.

20. The integrated circuit device of claim 18, wherein the DAC comprises a delta sigma DAC.

21. The integrated circuit device of claim 18, wherein the filter comprises a switched capacitor filter.

22. The integrated circuit device of claim 18, wherein the filter comprises a continuous time filter.

23. The integrated circuit device of claim 18, wherein the filter cancels a DC offset exhibited by the outbound audio bitstream that is supplied to the filter as the sidetone.

24. The integrated circuit device of claim 18, further comprising:

RF circuitry including the transmitter and receiver;

digital processing circuitry; and

a controller, coupled to the RF circuitry and the digital processing circuitry, that activates the RF circuitry and inactivates the digital processing circuitry during first periods of time, the controller inactivating the RF circuitry and activating the digital processing circuitry during second periods of time.

25. A wireless communication device comprising:

an analog to digital converter (ADC) that converts an outbound analog audio signal to an outbound audio bitstream;

a transmitter, coupled to the ADC, that transmits the outbound audio bitstream;

a receiver that receives an inbound digital audio bitstream;

a digital to analog converter (DAC), coupled to the receiver, that converts the inbound digital audio signal to an inbound audio bitstream; and

a filter, coupled to the ADC and the DAC, the filter both adding the outbound bitstream as a sidetone to the inbound audio bitstream to produce a resultant signal and also filtering the resultant signal to provide an analog audio signal with sidetone.

26. The wireless communication device of claim 25, wherein the ADC comprises a delta sigma ADC.

27. The wireless communication device of claim 25, wherein the DAC comprises a delta sigma DAC.

28. The wireless communication device of claim 25, wherein the filter comprises a switched capacitor filter.

29. The wireless communication device of claim 25, wherein the filter comprises a continuous time filter.

30. The wireless communication device of claim 25, wherein the filter cancels a DC offset exhibited by the outbound audio bitstream that is supplied to the filter as the sidetone.

31. The wireless communication device of claim 25, further comprising:

RF circuitry including the transmitter and receiver;

digital processing circuitry; and

a controller, coupled to the RF circuitry and the digital processing circuitry, that activates the RF circuitry and inactivates the digital processing circuitry during first periods of time, the controller inactivating the RF circuitry and activating the digital processing circuitry during second periods of time.