Spread spectrum arrangement for (de)multiplexing speech signals and nonspeech signals
First Claim
1. A signal processor including a first input terminal (105) adapted to receive a speech signal, a second input terminal (185) adapted to receive a nonspeech signal, means for multiplexing said speech signal and said nonspeech signal, means for extending said multiplexed signal to an output terminal (125), said output terminal adapted for transmitting said multiplexed signal to a receiver and characterized in thatsaid multiplexing means includes spread spectrum means (100) for multiplexing said speech signal and said nonspeech signal, said spread spectrum multiplexing means includingmeans (110) for delaying said speech signal,means (140) for converting said speech signal from a first domain to a second domain, said second domain signal having a plurality of components,means (130) for selecting one of said components,means (160) responsive to said selected component for providing a prediction of said selected component,means (170) responsive to said nonspeech signal for modifying said prediction,means (150) for converting said modified prediction from said second domain to said first domain, andmeans (120) for extending said delayed speech signal and said modified first domain signal to said output terminal.
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Abstract
It is known to multiplex speech signals and nonspeech signals over a common communication path. One arrangement uses a portion of the frequency spectrum of the path for speech signals with the remainder for nonspeech signals. Another inserts data signals during gaps in the speech signals. Still another treats a speech signal as a carrier signal and modulates the speech signal with data signals. Unfortunately, users of such known arrangements experience excessive distortion or perceive others as encroaching on the path. These and other problems are mitigated by my improved signal processor (100, 200) for the spread spectrum (de)multiplexing of speech signals and nonspeech signals. In an illustrative embodiment, at a transmitter, a block (110) of speech signals may be converted (140) from a time domain to a frequency domain by a Fourier transformation. A Fourier component may be pseudo-randomly selected (130) from a subset of such components. Responsive to the selected component, a prediction (160) of the component may be substituted therefor, the prediction being thereafter modified (170), e.g., by its amplitude being incremented or decremented to reflect the multiplexing of a logic 1 or a logic 0 nonspeech signal. The modified prediction may be converted (150) back to the time domain for transmission to a receiver. At the receiver, a parallel demultiplexing (200) occurs for extracting (270) speech signals and nonspeech signals from the multiplexed signals.
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Citations
8 Claims
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1. A signal processor including a first input terminal (105) adapted to receive a speech signal, a second input terminal (185) adapted to receive a nonspeech signal, means for multiplexing said speech signal and said nonspeech signal, means for extending said multiplexed signal to an output terminal (125), said output terminal adapted for transmitting said multiplexed signal to a receiver and characterized in that
said multiplexing means includes spread spectrum means (100) for multiplexing said speech signal and said nonspeech signal, said spread spectrum multiplexing means including means (110) for delaying said speech signal, means (140) for converting said speech signal from a first domain to a second domain, said second domain signal having a plurality of components, means (130) for selecting one of said components, means (160) responsive to said selected component for providing a prediction of said selected component, means (170) responsive to said nonspeech signal for modifying said prediction, means (150) for converting said modified prediction from said second domain to said first domain, and means (120) for extending said delayed speech signal and said modified first domain signal to said output terminal.
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5. A signal processor including a first input terminal (205) adapted to receive a multiplexed signal, means for demultiplexing said multiplexed signal, means for extending a nonspeech signal from said multiplexed signal to a first output terminal (285), means for extending a speech signal from said multiplexed signal to a second output terminal (225) and characterized in that said demultiplexing means includes spread spectrum means (200) for demultiplexing said multiplexed signal and for extracting a speech signal and a nonspeech signal from said multiplexed signal, said spread spectrum demultiplexing means including,
means (210) for delaying said multiplexed signal, means (240) for converting said multiplexed signal from a first domain to a second domain, said second domain signal having a plurality of components, means (230) for selecting one of said components, means (260) responsive to said selected component for providing a prediction of said selected component, means (270) responsive to said selected component and to said prediction for extracting said speech signal and said nonspeech signal, means (250) for converting said extracted speech signal from said second domain to said first domain, and means (220) for extending said delayed multiplexed signal and said extracted first domain speech signal to said second output terminal, and means for extending said extracted nonspeech second domain signal to said first output terminal.
Specification
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Current AssigneeBell Telephone Laboratories, Inc. (Nokia Corporation)
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Original AssigneeBell Telephone Laboratories, Inc. (Nokia Corporation)
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InventorsMaxemchuk, Nicholas F.
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Primary Examiner(s)Ng, Jin F.
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Assistant Examiner(s)Chin, Tommy P.
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Application NumberUS06/138,721Time in Patent Office657 DaysField of Search370/19, 370/23, 370/93, 370/108, 370/111, 375/1, 375/34, 375/50US Class Current370/210CPC Class CodesH04J 13/00 Code division multiplex sys...H04M 11/06 Simultaneous speech and dat...
