Digital wireless speaker system

• US 5,946,343 A
• Filed: 04/24/1998
• Issued: 08/31/1999
• Est. Priority Date: 11/22/1994
• Status: Expired due to Fees

• Current Assignee: LS Research, LLC (Laird Limited)
• Original Assignee: L S Research, Inc.
• Inventors: Steinike, William R., Wolski, Mark R., Schotz, Larry
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Liu, Shuwang
• Application Number:
  US09/066,721
• Time in Patent Office: 494 Days
• Field of Search: 375/200, 375/202, 375/206, 375/260, 375/209, 380/34, 348/525, 340/825.25, 381/14
• US Class Current: 375/141
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04H 20/61 for local area broadcast, e.g. instore broadcast
• CPC Class Codes: H04H 20/63 to plural spots in a confined site, e.g. MATV [Master Antenna Television]
• CPC Class Codes: H04H 20/71 Wireless systems
• CPC Class Codes: H04H 60/13 Arrangements for device control affected by the broadcast information
• CPC Class Codes: H04H 60/92 for local area
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04M 1/6066 including a wireless connection
• 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

Abstract

This invention discloses a digital wireless speaker system for use in consumer audio applications. A digital radio frequency transmitter is connected to an analog or digital audio source and a digital radio frequency receiver provides for reception of the transmitted audio information in remote locations. In addition, the digital receiver will be able to receive control information to implement such things as volume, tone controls, or other auxiliary information. This allows the user to listen to high quality audio in a variety of locations without the need of independent stereos or external wires. The system is based on digital circuitry to improve the performance of the system and provide for compact disc quality sound. The digital circuitry incorporates forward error correction techniques and interleaving to enable the system to account for errors in transmission and thus improve the overall performance of the system.

Claims

1. A high fidelity, digital wireless transmission, stereo audio system for use with at least one audio source which provides an audio input signal, said audio system arranged for wirelessly transmitting over the air an electrical signal representing said audio input signal, said stereo audio system comprising:

a transmitter arranged to be coupled to said at least one audio source, wherein said audio input signal comprises high fidelity, stereo audio information that is susceptible to RF dropout and comprising;

analog-to-digital converting means for converting said audio input signal into a digital audio interface signal at a high digital audio bit rate, thereby defining a source data rate;

a digital signal processor, coupled to said analog-to-digital converting means, for embedding a sync word into said digital audio interface signal at a transmit data rate, said transmit data rate being equal to said source data rate;

direct sequence spread spectrum means, coupled to said converting means, for generating baseband spread spectrum data from said digital serial bit stream signal, said direct sequence spread spectrum means including a processing gain of at least 10 dB;

carrier signal producing means for producing a carrier signal of at least 2.4 GHz;

modulation means for modulating said carrier signal with said baseband spread spectrum data to produce a modulated carrier signal;

first antenna means for emitting over the air said modulated carrier signal at a power level not exceeding approximately 1 watt; and

a receiver located within a range of approximately 10 to 300 feet (3 to 90 meters) of said transmitter and being coupled to an audio transducing device, said receiver receiving and demodulating said modulated carrier signal into an audio output signal, said receiver comprising;

a second antenna means for receiving said modulated carrier signal radiated from said first antenna;

demodulation means for demodulating said modulated carrier signal into a baseband digital signal;

direct sequence spread spectrum recovery means, coupled to said demodulation means, for decoding said baseband digital signal into digital audio data based on pseudonoise sequence acquisition and for recovering an associated clock;

output means for converting said digital audio data, in accordance with said clock, into an audio output signal having a format compatible with the audio transducing device, said output means outputting the left and right audio data to the audio transducing device upon detection of said embedded synchronization signal.