| 摘要 |
PURPOSE:To provide an A/D conversion system capable or improving S/N characteristics. CONSTITUTION:An A/D conversion circuit 2 converts an analog television picture signal into a digital signal. A flat part detecting circuit 4 detects the level state of a flat part in the digitized picture signal. A control circuit 5 generates a control signal for adjusting offset so that the digital signal of the flat part becomes a fixed PCM value. An offset circuit 1 adds an offset signal to the analog signal on the input side of the circuit 2 and offsets the analog signal so that the fixed PCM value is obtained in the required number of bits on the flat part of the digitized picture signal. |
