| 摘要 |
PURPOSE:To provide an inexpensive system having lots of common use parts while receiving both an analog modulation signal and a digital modulation signal. CONSTITUTION:A signal obtained from a band pass filter 12 is fed to phase detectors 13, 14, to which oscillation outputs from a voltage controlled oscillator 15 are fed with a phase difference of 90 deg.. When an analog modulation signal is received, the oscillating frequency of the voltage controlled oscillator 15 is controlled by an output of the detector 15 smoothed by a low pass filter 19 and when a digital modulation signal is received, the voltage controlled oscillator 15 is controlled by the output of a phase locked loop circuit 21 phase- locked to a fixed frequency oscillator 24. When the digital modulation signal is received, outputs of the phase detectors 13, 14 are led out respectively as a Q axis component and an I axis component from a switch 17. When the analog modulation signal is received, the output of the switch 17 is a video signal output.
|
