| 摘要 |
<p>A subcarrier regenerator circuit for use in color television receiver demodulators. The regenerator includes a voltage-controlled oscillator and a fixed frequency oscillator set to the nominal subcarrier frequency. During the vertical retrace period, a phase detector forces the output of the voltage-controlled oscillator to match that of the fixed-frequency oscillator. The output of the detector is also stored. During the active vertical scan, the phase detector compares the voltage-controlled oscillator output with the color burst synchronization signal and produces an output which is added with the stored output. The added signal is used to adjust the output of the voltage-controlled oscillator to match the color burst signal in phase and frequency, so that the output can be used by the synchronous color signal demodulators.</p> |
