Granted Patent B2

US 9,237,407 · App. 11/499,405 · Granted Jan 12, 2016

Abstract

Claims (54)

1. A method of operating a wireless digital audio distribution system to synchronize an output of audio data by receiving units, wherein a transmitting unit provides for a wireless packet transmission of audio data for receipt by a plurality of receiving units, said method comprising the steps of:

a) generating a sequence of audio data packets wherein each said data packet includes parallel data respectively representing a plurality of audio data channels;

b) broadcasting wirelessly, by said transmitter unit, said sequence of audio data packets, wherein said transmitter unit includes a timing marker in first predetermined ones of said audio data packets;

c) receiving wirelessly, by a predetermined one of said plurality of receiving units, said sequence of audio data packets;

d) selecting, from a second predetermined one of said audio data packets, parallel data respectively representing a predetermined one of said plurality of audio data channels;

e) outputting, said parallel data respectively representing a predetermined one of said plurality of audio data channels synchronized to a receipt of said timing marker by said receiving unit;

f) detecting, by said predetermined one of said plurality of receiving units, a transmission data error in a predetermined one of said first predetermined ones of said audio data packets; and

g) correcting said transmission data error including selection of a predetermined one of said redundantly broadcast audio data packets in replacement of said predetermined one of said first predetermined ones of said audio data packets; and wherein said step of correcting includes successively performing correction by:

h) first correcting said transmission data error using forward error correction to correct errors in the audio data transferred by said predetermined one of said first predetermined ones of said audio data packets;

i) second correcting said transmission data error, where said step of first correcting fails, by replacement of said predetermined one of said audio data packets; and

j) third correcting said transmission data error, where said step of second correcting fails, by interpolation using the audio data transferred by a select one of said sequence of audio data packets to construct substitute audio data in replacement for the audio data transferred by said predetermined one of said first predetermined ones of said audio data packets, wherein said select one of said sequence of audio data packets is received by said predetermined one of said plurality of receiving units prior to said predetermined one of said first predetermined ones of said audio data packets.

2. A wireless digital audio distribution system providing for high-bitrate, multichannel distribution of digital audio data streams with controlled, low playback to source latency and channel to channel phase coherency, said wireless digital audio distribution system comprising:

a) a wireless transmitter, coupleable to a multichannel audio stream source, said wireless transmitter including

i) an encoding packet data processor operative to generate a sequence of audio data packets wherein each said audio data packet encodes samples of a plurality of digital audio data streams as parallel data respectively representing said plurality of digital audio data streams, predetermined ones of said sequence of audio data packets being encoded with a timing marker; and

ii) a radio transmitter coupled to said encoding packet data processor to transmit wirelessly said sequence of audio data packets; and

b) a plurality of wireless receivers, coupleable to a respective plurality of audio speakers, each said wireless receiver including

i) a radio receiver operative to receive said sequence of audio data packets from said wireless transmitter; and

ii) a decoding packet data processor, coupled to said radio receiver, said decoding packet data processor being operative to decode from each audio data packet of said sequence of audio data packets parallel data representing a predetermined one of said plurality of digital audio data streams to produce a sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams, said decoding package data processor including a buffered output stage operative to output said sequential series of samples synchronized with said timing markers;

wherein (a) said encoding packet data processor includes a transmitter master timing system, wherein said transmitter master timing system is operative to provide a temporally controlled alignment signal determinative of the transmission rate of said predetermined ones of said sequence of audio data packets encoded with said timing marker;

wherein (b) each said decoding packet data processor includes a receiver master timing system responsive to receipt of said timing markers, and wherein said buffered output stage is responsive to said receiver master timing system to output said sequential series of samples synchronized to said timing markers with a predetermined time delay;

wherein (c) said encoding packet data processor is further operative to encode said samples of said plurality of digital audio data streams with forward error correction information and wherein said decoding packet data processor is further operative to decode and correct said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams;

wherein (d) said sequence of audio data packets includes primary and redundant samples of said plurality of digital audio data streams in said parallel data respectively representing said plurality of digital audio data streams, said decoding packet data processor being further operative to select between using primary and redundant samples reproducing said predetermined one of said plurality of digital audio data streams; and

wherein (e) said decoding packet data processor, in response to transmission data errors, is further operative to

c) first correct a transmission data error using forward error correction to correct errors in a predetermined primary sample included in said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams;

d) second correct said transmission data error, where said first correction fails, by substitution of a corresponding redundant sample included in said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams, said decoding packet data processor being operative to perform said first correct with respect to said corresponding redundant sample; and

e) third correct said transmission data error, where said second correct fails, by interpolation using a known sample included in said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams to construct a substitute sample in replacement of said predetermined primary sample, wherein said known sample occurs before said predetermined primary sample in said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams.

3. The wireless digital audio distribution system of claim 2 wherein said redundant samples of said plurality of digital audio data streams are provided as parallel data respectively representing said plurality of digital audio data streams in redundant audio data packets interleaved in said sequence of audio data packets transmitted by said wireless transmitter said redundant audio data packets being excluded from said predetermined ones of said sequence of audio data packets encoded with said timing marker.

4. The wireless digital audio distribution system of claim 3 wherein said predetermined time delay is programmable.

5. A method of operating a wireless digital audio distribution system to synchronize an output of audio data by receiving units, wherein a transmitting unit provides for a wireless packet transmission of audio data for receipt by a plurality of receiving units, said method comprising the steps of:

a) generating a sequence of audio data packets wherein each said data packet includes parallel data respectively representing a plurality of audio data channels;

b) broadcasting wirelessly, by said transmitter unit, said sequence of audio data packets, wherein said transmitter unit includes a timing marker in first predetermined ones of said audio data packets;

c) receiving wirelessly, by a predetermined one of said plurality of receiving units, said sequence of audio data packets;

d) selecting, from a second predetermined one of said audio data packets, parallel data respectively representing a predetermined one of said plurality of audio data channels;

e) outputting, said parallel data respectively representing a predetermined one of said plurality of audio data channels synchronized to a receipt of said timing marker by said receiving unit;

f) detecting, by said predetermined one of said plurality of receiving units, a transmission data error in a predetermined one of said first predetermined ones of said audio data packets; and

g) correcting said transmission data error including selection of a predetermined one of said redundantly broadcast audio data packets in replacement of said predetermined one of said first predetermined ones of said audio data packets, wherein correction is successively performing by:

i) first correcting said transmission data error using forward error correction to correct errors in the audio data transferred by said predetermined one of said first predetermined ones of said audio data packets;

ii) second correcting said transmission data error, where said step of first correcting fails, by replacement of said predetermined one of said audio data packets; and

h) third correcting said transmission data error, where said step of second correcting fails, by interpolation using the audio data transferred by a select one of said sequence of audio data packets to construct substitute audio data in replacement for the audio data transferred by said predetermined one of said first predetermined ones of said audio data packets, wherein said select one of said sequence of audio data packets is received by said predetermined one of said plurality of receiving units prior to said predetermined one of said first predetermined ones of said audio data packets.

6. A wireless digital audio distribution system providing for high-bitrate, multichannel distribution of digital audio data streams with controlled, low playback to source latency and channel to channel phase coherency, said wireless digital audio distribution system comprising:

a) a wireless transmitter, coupleable to a multichannel audio stream source, said wireless transmitter including

i) an encoding packet data processor operative to generate a sequence of audio data packets wherein each said audio data packet encodes samples of a plurality of digital audio data streams as parallel data respectively representing said plurality of digital audio data streams, predetermined ones of said sequence of audio data packets being encoded with a timing marker; and

ii) a radio transmitter coupled to said encoding packet data processor to transmit wirelessly said sequence of audio data packets; and

b) a plurality of wireless receivers, coupleable to a respective plurality of audio speakers, each said wireless receiver including

i) a radio receiver operative to receive said sequence of audio data packets from said wireless transmitter; and

ii) a decoding packet data processor, coupled to said radio receiver, said decoding packet data processor being operative to decode from each audio data packet of said sequence of audio data packets parallel data representing a predetermined one of said plurality of digital audio data streams to produce a sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams, said decoding package data processor including a buffered output stage operative to output said sequential series of samples synchronized with said timing markers,

wherein said encoding packet data processor includes a transmitter master timing system, wherein said transmitter master timing system is operative to provide a temporally controlled alignment signal determinative of the transmission rate of said predetermined ones of said sequence of audio data packets encoded with said timing marker,

wherein each said decoding packet data processor includes a receiver master timing system responsive to receipt of said timing markers, and wherein said buffered output stage is responsive to said receiver master timing system to output said sequential series of samples synchronized to said timing markers with a predetermined time delay,

wherein said encoding packet data processor is further operative to encode said samples of said plurality of digital audio data streams with forward error correction information and wherein said decoding packet data processor is further operative to decode and correct said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams,

wherein said sequence of audio data packets includes primary and redundant samples of said plurality of digital audio data streams in said parallel data respectively representing said plurality of digital audio data streams, said decoding packet data processor being further operative to select between using primary and redundant samples reproducing said predetermined one of said plurality of digital audio data streams, and

wherein said decoding packet data processor, in response to transmission data errors, is further operative to

a) first correct a transmission data error using forward error correction to correct errors in a predetermined primary sample included in said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams;

b) second correct said transmission data error, where said first correction fails, by substitution of a corresponding redundant sample included in said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams, said decoding packet data processor being operative to perform said first correct with respect to said corresponding redundant sample; and

c) third correct said transmission data error, where said second correct fails, by interpolation using a known sample included in said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams to construct a substitute sample in replacement of said predetermined primary sample, wherein said known sample occurs before said predetermined primary sample in said sequential series of samples reproducing said predetermined one of said plurality of digital audio data streams.

Assignments (10)