| 摘要 |
<p>SYSTEM FOR GENERATING SECAM COLOR CARRIER SIGNALS An oscillator signal approximately equal to 282 times the horizontal line frequency and a second oscillator signal approximately equal to 272 times the horizontal line frequency are each applied to frequency dividers, the output of the frequency dividers having a frequency substantially equal to the horizontal line frequency. A phase comparator compares the output of each frequency divider to a reference signal of horizontal line frequency. The first and second soderived difference signals are applied through respective low pass filters to the respective oscillators thereby adjusting the frequency of the respective oscillators to be exactly 282 and 272 times the horizontal line frequency as required for the two color carrier frequencies respectively. In one embodiment the frequency division is carried out by binary frequency dividers. In other embodiments the frequency division is carried out by mixing the two oscillator frequencies with a signal having a frequency equal to 277 times the horizontal line frequency.</p> |
