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AssigneeBell Telephone Laboratories, Incorporated
InventorsDavid Gavin Messerschmitt, Timothy James Zebo
Estimating the term…
In a communications system such as a time assignment speech interpolation (TASI) system for concentrating signals from N trunks onto C channels (C < N), and for expanding same, it is common for a speech signal to pass through a plurality of transmitter/receiver terminals, perhaps connected for tandem operation. Unfortunately, transmitter speech detector clipping of the speech signal leads to a distortion accumulation problem. Also, while a calling trunk is inactive, an inserted noise signal is commonly furnished by a receiver to the called trunk to avoid an aural "too quiet" condition. Unfortunately, actual calling trunk noise and the called trunk inserted noise may differ, leading to a noise signal contrast problem. To mitigate the signal contrast problem, communications apparatus including an improved noise signal inserting arrangement, responsive to a measure of calling trunk noise, supplies an adaptively adjusted, deterministic, pseudorandom noise signal to the called trunk. Thereafter, the presence or absence of the deterministic signal may be detected at a tandem transmitter and, responsive to its absence, the speech detector, at the tandem transmitter is overridden to mitigate the distortion accumulation of speech signal clipping.
Digital communications apparatus having an input terminal adapted to receive a first input signal from a trunk and having an output terminal adapted to transmit an output signal to a channel, said communications apparatus including detection apparatus for detecting the activity status of said trunk and extension apparatus responsive to a first trunk activity status for extending a representation of said first input signal to said output terminal and characterized in that said communications apparatus further comprises:
Digital communications apparatus having an input terminal adapted to receive a first input signal from a trunk and having an output terminal adapted to transmit an output signal to a channel, said communications apparatus including detection apparatus for detecting the activity status of said trunk and extension apparatus responsive to a first trunk activity status for extending representation of said first input signal to said output terminal and characterized in that said communications apparatus further comprises:
Communications apparatus having an input terminal adapted to receive a first input signal from a trunk and having an output terminal adapted to transmit an output signal to a channel, said communications apparatus including detection apparatus for detecting the activity status of said trunk and extension apparatus responsive to a first trunk activity status for extending a representation of said first input signal to said output terminal and characterized in that said communications apparatus further comprises:
Communications apparatus having an input terminal adapted to receive an input signal from a trunk and having an output terminal adapted to transmit an output signal to a channel, said communications apparatus including detection apparatus for detecting the activity status of said trunk, characterized in that said communications apparatus further comprises:
Communications apparatus having an input terminal adapted to receive an input signal and having an output terminal adapted to transmit an output signal, said communications apparatus including detection apparatus for detecting the activity status at said input terminal and extension apparatus responsive to a first activity status state for extending a representation of said input signal to said output terminal, characterized in that said communications apparatus further comprises:
Dependencies are inferred from the claim text.