| 摘要 |
<p>PURPOSE:To input a PCM signal of normal level to a high-efficiency encoding device at all time by adjusting a gain according to variation in the level of the synchronizing signal of a television signal even if its input amplitude varies. CONSTITUTION:An A/D converting circuit 3 converts the television signal into linear PCM and an amplitude detecting circuit 5 detects the amplitude of the synchronizing signal of the television signal from the output of the A/D converting circuit 3. A ROM 4 for gain adjustment multiplies the output value of the A/D converting circuit 3 by a coefficient according to the output of the amplitude detecting circuit 5. Consequently, the PCM signal of normal level can be inputted to the high-efficiency encoding device at all times.</p> |
