Single-channel-per-carrier communication system including a voice-activated transmission power controller
First Claim
Patent Images
1. A single channel-per-carrier modulation system comprising:
- modulator means for modulation an input carrier wave in response to an input channel signal and providing a modulated carrier wave;
detector means for detecting the presence of the input channel signal;
gate circuit means responsive to a channel connection signal for supplying the input carrier wave to the modulator means only when the channel connection signal indicates that the associated channel is in the connection; and
level control means responsive to at least the output of the detector means for imparting to the modulated carrier wave a predetermined attenuation when the associated channel is in connection but there is no input channel signal present, whereby the modulated carrier wave is continuously transmitted when the associated channel is in connection, regardless of the presence or absence of an input channel signal.
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Abstract
A single-channel-per-carrier multiple-access communication system including a voice-activated transmission power controller operable in the absence of voice signal input to attenuate the transmission power or modulator output signal to a predetermined level under the control of voice detector output, facilitating carrier sync recovery at the receive end and simplifying design and structure of the demodulator.
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Citations
7 Claims
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1. A single channel-per-carrier modulation system comprising:
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modulator means for modulation an input carrier wave in response to an input channel signal and providing a modulated carrier wave; detector means for detecting the presence of the input channel signal; gate circuit means responsive to a channel connection signal for supplying the input carrier wave to the modulator means only when the channel connection signal indicates that the associated channel is in the connection; and level control means responsive to at least the output of the detector means for imparting to the modulated carrier wave a predetermined attenuation when the associated channel is in connection but there is no input channel signal present, whereby the modulated carrier wave is continuously transmitted when the associated channel is in connection, regardless of the presence or absence of an input channel signal. - View Dependent Claims (2)
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4. A single channel-per-carrier modulation system comprising:
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detector means for detecting the presence of an input channel signal; modulator means for modulating an input carrier wave in response to a modulating signal and providing a modulated carrier wave; gate circuit means responsive to a channel connection signal for supplying the input carrier wave to the modulator means only when the channel connection signal indicates that the associated channel is in connection; and level control means responsive to the output of the detector means for imparting to the input channel signal a predetermined attenuation when the associated channel is in connection but there is no input channel signal present, whereby the modulated carrier wave is continuously transmitted when the associated channel is in connection, regardless of the presence or absence of an input channel signal. - View Dependent Claims (3, 5, 6, 7)
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Specification