| 摘要 |
<p>PURPOSE:To constitute an error operating circuit with low-speed elements by operating an error only with a digital signal outputted in every period of color subcarrier wave. CONSTITUTION:A closed loop composed of an A/D converter 11, a burst extracting circuit 14, a pedestal level generator 41, a pedestal level error operation circuit 40, a D/A converter 42, a loop filter 43, and an analog adder 44 constitutes a control circuit to clamp the pedestal level of a composite color television signal so as to consist with a targeted value from the pedestal level generator 41, clamping the pedestal level digitally. An error operated by the error operating circuit 45 is applied to the control terminal of a voltage control oscillator 18 through a D/A converter 16 and a loop filter 17.</p> |
