Wireless infrared digital audio receiving system
First Claim
1. A receiving system for receiving a modulated carrier signal from a communication medium, whereby said modulated carrier signal contains digitized samples of an analog signal comprising:
- a receiver connected to the communication medium to recover said modulated carrier signal and extract a modulated transmit frame;
a demodulator connected to said receive to demodulate the modulated transmit frame and recover the transmit frame and extract the groups of interleaved multiple digitized samples of the analog signals with the appended error correction code;
a received data buffer to retain the group of interleaved multiple digitized samples of the analog signals with the appended error correction code;
a received data buffer controller connected to the demodulator and the received data buffer to control transfer of the group of interleaved multiple digitized samples of the analog signals with the appended error correction code from the demodulator to the received data buffer;
an error check and correction circuit connected to the received data buffer controller to receive one group of the multiple digitized samples of the analog signals with the appended error correction code, to check and correct errors in said one of the multiple digitized samples analog signals, to replace the corrected one group of the multiple digitized samples of the analog signals to the received data buffer, and to identify any non-correctable group of the multiple digitized samples analog signals;
a block recovery circuit connected to the received data buffer controller to interpolate the non-correctable group of the multiple digitized samples of the analog signals to conceal an effect of said non-correctable group of the multiple digitized samples analog signals;
a soft muting circuit connected to the received data buffer controller to access those the multiple digitized samples of the analog signals with non-recoverable and non-concealable errors and those of the multiple digitized samples of the analog signals that are correct and adjacent to the multiple digitized samples of the analog signals with non-correctable and non-concealable errors, to apply a smoothing function to said multiple digitized samples of the analog signals to bring those of the multiple digitized samples of the analog signals with the non-correctable and non-concealable error to a null value;
a jitter tracking circuit to compare a block transmission timing signal with a clock signal of said receiver subsystem to determine overrun and underrun of the contents of the group of interleaved multiple digitized samples of the analog signals with the appended error correction code, whereby said block transmission timing signal indicates a boundary between groups of the multiple interleaved digitized samples analog signals;
an interpolation and decimation circuit connected to the jitter tracking circuit and the received data buffer controller to generate or eliminate digitized samples of the analog signals if the jitter tracking circuit indicates overrun or underrun of the contents of the group of interleaved multiple digitized samples analog signals; and
an interface circuit connected to the received data buffer controller to translate the digitized samples of the analog signals to a format acceptable by subsequent circuitry.
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Accused Products
Abstract
A system for transmitting, receiving, recovering, and reproducing digitized samples of analog signals while concealing unrecoverable digitized samples of analog signals to maintain a level of fidelity in reproducing the analog signals. The digitized samples of the analog signals are burst transmitted such that the probability of interference with the transmission and thus corruption of the digitized samples of the analog signals is minimized. The digitized samples are received without synchronizing a receiving clock with a transmitting clock to capture the digitized samples of the analog signals. The digitized samples are converted from various sampling rates to digitized samples of the analog signals having a rate. Any large groups of digitized samples that are in error or corrupted in transmission are softly muted to avoid annoying clicks. Any long term difference between a transmit clock and a receive clock is tracked and the digitized samples are interpolated or decimated to eliminate any underrun or overrun of the digitized samples.
39 Citations
36 Claims
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1. A receiving system for receiving a modulated carrier signal from a communication medium, whereby said modulated carrier signal contains digitized samples of an analog signal comprising:
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a receiver connected to the communication medium to recover said modulated carrier signal and extract a modulated transmit frame;
a demodulator connected to said receive to demodulate the modulated transmit frame and recover the transmit frame and extract the groups of interleaved multiple digitized samples of the analog signals with the appended error correction code;
a received data buffer to retain the group of interleaved multiple digitized samples of the analog signals with the appended error correction code;
a received data buffer controller connected to the demodulator and the received data buffer to control transfer of the group of interleaved multiple digitized samples of the analog signals with the appended error correction code from the demodulator to the received data buffer;
an error check and correction circuit connected to the received data buffer controller to receive one group of the multiple digitized samples of the analog signals with the appended error correction code, to check and correct errors in said one of the multiple digitized samples analog signals, to replace the corrected one group of the multiple digitized samples of the analog signals to the received data buffer, and to identify any non-correctable group of the multiple digitized samples analog signals;
a block recovery circuit connected to the received data buffer controller to interpolate the non-correctable group of the multiple digitized samples of the analog signals to conceal an effect of said non-correctable group of the multiple digitized samples analog signals;
a soft muting circuit connected to the received data buffer controller to access those the multiple digitized samples of the analog signals with non-recoverable and non-concealable errors and those of the multiple digitized samples of the analog signals that are correct and adjacent to the multiple digitized samples of the analog signals with non-correctable and non-concealable errors, to apply a smoothing function to said multiple digitized samples of the analog signals to bring those of the multiple digitized samples of the analog signals with the non-correctable and non-concealable error to a null value;
a jitter tracking circuit to compare a block transmission timing signal with a clock signal of said receiver subsystem to determine overrun and underrun of the contents of the group of interleaved multiple digitized samples of the analog signals with the appended error correction code, whereby said block transmission timing signal indicates a boundary between groups of the multiple interleaved digitized samples analog signals;
an interpolation and decimation circuit connected to the jitter tracking circuit and the received data buffer controller to generate or eliminate digitized samples of the analog signals if the jitter tracking circuit indicates overrun or underrun of the contents of the group of interleaved multiple digitized samples analog signals; and
an interface circuit connected to the received data buffer controller to translate the digitized samples of the analog signals to a format acceptable by subsequent circuitry. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for receiving, and recovering digitized samples of analog signals comprising the steps of:
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receiving a modulated carrier signal;
demodulating said modulated carrier signal to recover said transmit frame;
extracting a plurality of groups of interleaved digitized samples with appended error correction codes from the recovered transmit frame;
checking and correcting the groups of interleaved digitized samples;
if any of the digitized samples have uncorrectable errors, concealing any effect of said uncorrectable errors by interpolating from adjacent correct digitized samples an estimate of a sample value of said digitized samples with uncorrectable errors;
comparing a block transmission timing signal with a receiver clock signal to track jitter between said receiver clock and said block transmission timing signal to determine overrun and underrun of the contents of the group of interleaved multiple digitized samples of the analog signals with the appended error correction code;
interpolating and decimating to generate or eliminate digitized samples of the analog signals if the jitter tracking circuit indicates overrun or underrun of the contents of the group of interleaved multiple digitized samples analog signals; and
soft muting any of the digitized samples that have uncorrectable or non-concealable errors; and
transferring the digitized samples to a digital-to-analog converter to restore the analog signal. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification