Wireless Digital Transmission of Low Frequency Effects and Surround Channels For Surround Sound System

• US 20080247554A1
• Filed: 09/22/2004
• Published: 10/09/2008
• Est. Priority Date: 09/24/2003
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Caffrey, John Justin
• Granted Patent: US 8,340,313 B2
• Time in Patent Office: Days
• US Class Current: 381/18
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S
• CPC Class Codes: H04S 3/00 Systems employing more than two channels, e.g. quadraphonic H04S5/00, H04S7/00 take precedence

Abstract

A subwoofer (72) is equipped with a wireless receiver (80) to receive signals containing information for a Low Frequency Effects (LFE) channel and information for both surround channels. In one form, the LFE is added to one or both surround channels to provide a stereo surround signal (containing both surround channels including a multiplexed LFE channel). The subwoofer (72) utilizes the LFE channel, powers surround speakers (74, 76), and passes the surround signals to respective surround speakers. A receiver (66) multiplexes LFE signals into either one or both surround sound audio channels. A digital RF transmitter (70) of the receiver transmits the combined subwoofer/surround channels to the wireless receiver (80) of the subwoofer. The remote subwoofer is connected to a power source (78). The surround speakers (74, 76) are connected to the subwoofer so as to receive the surround channels and be powered thereby.

Claims

1. A wireless subwoofer for use in a surround sound system, the wireless subwoofer comprising:

a receiver for wirelessly receiving a signal including both subwoofer and surround components; and

an extractor for extracting the subwoofer component from the received signal to drive the subwoofer;

wherein the subwoofer provides the surround component to a surround speaker to drive the surround speaker.

2. The wireless subwoofer of claim 1, wherein the receiver wirelessly receives a signal having a subwoofer component comprising a low frequency effects component.

3. The wireless subwoofer of claim 1, wherein the receiver wirelessly receives a signal having bass frequency audio components.

4. The wireless subwoofer of claim 1, wherein the extractor includes a digital demultiplexer to digitally demultiplex the subwoofer component which has been digitally multiplexed with the surround component from the received signal.

5. The wireless subwoofer of claim 1, wherein the receiver wirelessly receives a signal including both subwoofer and surround components that have been digitally multiplexed with one another and encoded to a predefined format using eight to fourteen modulation.

6. The wireless subwoofer of claim 1, wherein the receiver wirelessly receives a signal including both subwoofer and surround components wherein the subwoofer component has been summed with the surround component, converted to a pulse code modulation format and encoded into a predefined format using eight to fourteen modulation, and the extractor extracts the subwoofer component from the received signal to drive the subwoofer by demodulating the eight to fourteen modulation signals to derive pulse code modulation signals, and converts the derived pulse code modulation signals to analog subwoofer signals and analog surround signals to respectively drive the subwoofer and the surround speakers.

7. The wireless subwoofer of claim 6, wherein the extractor further includes a low pass filter for filtering out the subwoofer component, and the subwoofer further comprises an amplifier for amplifying the analog subwoofer and surround signals.

8. A surround sound receiver comprising:

a first port for connecting to a first front speaker;

a second port for connecting to a second front speaker;

a combiner for combining signals from subwoofer and surround channels; and

a transmitter for wirelessly transmitting the combined signal to a subwoofer;

wherein the subwoofer wirelessly receives the combined signal, extracts the subwoofer channel from the combined signal, powers surround speakers, and provides a signal including the surround channels to the surround speakers.

9. The surround sound receiver of claim 8, wherein the combiner comprises:

a digital multiplexer for digitally multiplexing the subwoofer and surround channels.

10. The surround sound receiver of claim 8, wherein the combiner combines signals from subwoofer and surround channels, the subwoofer channel including an low frequency effects component.

11. The surround sound receiver of claim 8, wherein the combiner combines signals from subwoofer and surround channels, the subwoofer channel having bass frequency audio components.

12. The surround sound receiver of claim 8, wherein the combiner combines signals from subwoofer and surround channels that are digitally multiplexed with one another and encoded to a predefined format using eight to fourteen modulation.

13. The surround sound receiver of claim 8, wherein the combiner combines signals from subwoofer and surround channels that have been summed, converted to a pulse code modulation format and encoded into a predefined format using eight to fourteen modulation.

14. A method of driving a surround sound subsystem having a subwoofer and surround sound speakers, the method comprising the steps of:

combining, at a surround sound receiver, a subwoofer signal with and surround signals;

wirelessly transmitting the combined signal via a digital RF transmitter associated with the surround sound receiver;

receiving the wirelessly transmitted combined signal with a wireless digital RF receiver associated with the subwoofer; and

providing the surround signals, by the subwoofer, to the surround sound speakers connected to the subwoofer to drive the surround sound speakers with the surround signals.

15. The method of claim 14, wherein the combining step includes digitally multiplexing the subwoofer signal with the surround signals.

16. The method of claim 15, wherein the combining step further includes converting the digitally multiplexed signals into a predefined format using eight to fourteen modulation.

17. The method of claim 15, further comprising the step of extracting the subwoofer signal form the combined signal to drive the subwoofer with the extracted subwoofer signal.

18. The method of claim 17, wherein the extracting step includes demultiplexing the subwoofer signal from the surround signals.

19. The method of claim 14, wherein the combining step includes:

summing the subwoofer signal with the surround signals in analog format;

converting the summed signals to a pulse code modulation format; and

encoding the pulse code modulation format signal using eight to fourteen modulation.

20. The method of claim 19, wherein the extracting step includes:

demodulating the eight to fourteen modulation signal to obtain pulse code modulation signals; and

converting the pulse code modulation signals to analog audio.