| 摘要 |
<p>PURPOSE:To obtain a high definition reception picture quality with simple configuration by executing the calculation of a clamp level, the detection and quantization of noise quantity, automatic gain control, etc., in a central processing unit in a concentrated way. CONSTITUTION:The DC level of an input signal is reproduced, the A/D conversion gain of the input signal is controlled, the quantity of a noise mixed in either a transmitting process or a recording process is detected, and controls noise reduction without the sense of incongruity in the sense of sight by writing an A/D converted signal through a digital filter having a variable characteristic to a RAM 35, reading out the A/D converted signal by a CPU 38, and calculating the A/D converted signal. Further, both the control system of an input level and a clamp level control system are processed in the CPU 38 in the concentrated way. Thus, the mutual interference between the system of the automatic gain control of the input level and the clamp level control system can be reduced, and a stable receiving system having satisfactory response characteristics can be realized with simple hardware configuration.</p> |
