| 摘要 |
PURPOSE:To secure excellent transmission quality with limited sending power by using a high frequency signal at the top end of a video signal band or outside of said band as a horizontal synchronizing signal, and maximizing the frequency shift of a video signal within a permissible range. CONSTITUTION:A frequency demodulating circuit 31 demodulates a TV signal 20 and a band-pass filter 32 extracts a high frequency signal 21 containing the horizontal synchronizing signal from the demodulated signal. An envelope detection circuit 33 detects the envelopes of the output signal of the filter 32 to extract a horizontal synchronizing frequency component. A synchronizing pulse and gate signal generating circuit 34 generate various gate signals and horizontal synchronizing pulses. A synchronizing pulse inserting and clamping circuit 35 replaces the horizontal synchronizing signal part in the demodulated signal passed through a delay device 36 from the demodulating circuit 31 by the horizontal synchronizing pulses from the circuit 34 on the basis of the gate signals of the circuit 34 to perform DC regeneration. The resulting signal provides a television composite signal similar to the signal for a normal TV receiver. |
