| 摘要 |
PROBLEM TO BE SOLVED: To provide a video encoder and a video decoder between which loopback of its own station aiming at a fault analysis is conducted without the need for an externally mounted mixer and a local signal generator SG. SOLUTION: A modulator 2 of the video encoder is provided with an orthogonal modulator 15 that outputs a phase modulation signal on the basis of signals obtained by giving two orthogonal modulation signals and two 1st local signals with a phase difference of 90-degrees to mixers 13, 14 respectively, a 3rd mixer 18 that receives the phase modulation signal and a 2nd local signal to provide an IF output signal for the modulator, a 4th mixer 22 that receives the IF output signal and a local signal for generating its own station loopback signal and that provides an output of the IF output signal for its own station loopback, and that can selectively output the IF output signal or the IF output signal for its own station loopback.
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