| 摘要 |
PURPOSE:To detect a carrier wave in a quick and assured way and without responding to noise, by providing the 1st BPF which delivers the 1st signal and arithmetic circuit which produces the 2nd signal related to the vector length for the complex display of the 1st signal. CONSTITUTION:A demodulator DEM is connected to a signal input terminal 10. The output 12 of one side of the DEM is connected to an equalizer EQ, and the other output is connected to the 1st BPF1 of a carrier detector. The BPF1 extracts a frequency component near the frequency equal to half of Band speed out of the base band signal which is demodulated by a modulated carrier wave and then extracts the 1st signal. The output of the BPF1 is connected to the 2nd BPF2 via a power calculating circuit PW, and the output of the BPF2 is connected to a threshould value detector DET. The DET produces a signal showing the carrier detection to an output 22 when the signal S3 of an input 20 exceeds the prescribed threshold value. |
