| 摘要 |
PROBLEM TO BE SOLVED: To simplify a detector and to reduce power consumption of the detector by unnecessitating an adaptive filtering by detecting the amplitude of an in-phase component I and a quadrature phase component Q of a demodulation signal respectively through a moving average filter in the detection of frequency burst in a cable communication system. SOLUTION: In a rough frequency burst detector 950, inverse rotation signals In ', Qn ' are obtained by compensating an oscillation frequency offset error dθof A/D converterd In , Qn signals by a compensator 110 of a phase shifter 100 and shifting phases by -πK/2 radian by a derotator 120. Then, a moving average of the components I, Q is calculated through the moving average filters 300, 400, the amplitude is detected by amplitude detectors 500, 600, the amplitude is synthesized by an accumulator 700 and supplied to a threshold value detector 800. Consequently, the speed of the detector is increased, the power consumption of the detector is reduced and calculation resources are simultaneously and effectively utilized by unnecessitating the adaptive filtering processing.
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