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US 5,347,534 AGranted
Automatic gain control system
AssigneeClarion Co., Ltd.
InventorsShigeo Akazawa, Masaharu Mori, Masahiro Hamatsu
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Abstract
A spread spectrum receiver includes, for example, a correlator consisting of two convolvers whose correlation outputs are applied to a demodulator respectively via two variable gain amplifiers whose gains are controlled in response to a demodulation output from the demodulator.
Claims2
A carrier sense apparatus in a spread spectrum receiver comprising:
- correlation means for correlating a reference signal and a spread spectrum signal received by the receiver;
- a demodulator for demodulating data from a correlation output from said correlation means;
- variable gain amplifier means provided between said correlation means and said demodulator to amplify said correlation output;
- gain control means for comparing a correlation spike from said demodulator with positive or negative first and second threshold voltages according to the polarity of the correlation spike and for producing a gain control signal responsive to a result of said comparison to control the gain of said variable gain amplifier means to maintain the peak of said correlation spike between said positive or negative first and second threshold voltages;
- and
- carrier sense means for comparing a first signal corresponding to said gain control signal with a second signal for comparison with the first signal to provide a carrier sense signal responsive to whether the first signal is larger than the second signal or not to determine whether or not a signal corresponding to the reference signal is transmitted.
3 more elements
Dependencies are inferred from the claim text.