| 摘要 |
<p>The chrominance signal is introduced by a subscriber modulation method, with periodic switching over at line frequency. It comprises a switching voltage generator and at least one synchronous demodulator with a first input to which a part of the chrominance signal is applied, and a second input, to which an oscillation of the subcarrier frequency is constantly applied. It comprises further a switching circuit responding to the switching voltage phase and controlling the phase of the above oscillation; and a second circuit responding to the demodulator output and correspondingly controlling the phase of the switching voltage.</p> |
