04313197 is referenced by 213 patents and cites 7 patents.

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.

Spread spectrum arrangement for (de)multiplexing speech signals and nonspeech signals
Application Number
Publication Number
Application Date
April 9, 1980
Publication Date
January 26, 1982
Nicholas F Maxemchuk
Richard J Roddy
Bell Telephone Laboratories Incorporated
H04J 3/02
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