| 摘要 |
<p>PURPOSE:To extend the application of the TV synchronization by sampling with the frequency of multiplication of the TV frame frequency by a rational number, to transmit the TV signal at a transmission rate within the spe cifications by a TV synchronization of excellent picture quality. CONSTITUTION:A PLL2 generates the sampling frequency from the TV signal of the image picked up by a camera 1. In this case, in the circuit 2, the frame frequency is detected from the TV signal by a frame frequency detecting circuit 21, and a correspondent clock is generated. Meanwhile, the output of a VCO22 that generates the sampling frequency is divided by a dividing circuit 22, and a clock is generated. The phase difference between this clock and the output from the circuit 21 is checked by a comparator 24. Then the clock is smoothed by a smoothing circuit 25, and the result is supplied to the control terminal of a VCO22. In result, the VCO22 generates a sampling frequency of the product of the frame frequency and the value decided by the circuit 23, therefore, the frame frequency is given a clock.</p> |
