| 摘要 |
PURPOSE:To attain almost complete linear automatic gain adjustment by applying digital processing to a reception pilot signal and applying level adjustment in response to input level fluctuation based on the processed signal. CONSTITUTION:An input sound signal is branched by a hybrid circuit 1 and outputted to an amplifier circuit 2 and a BPF 4. The pilot signal is extracted by the BPF 4. The extracted signal is converted into a DC voltage by a rectifier circuit 5. The DC voltage is sampled and coded by a pulse coding circuit 6. A ROM integrated circuit 7 stores the adjustment content to a level adjusting circuit 3 and reads the proper adjustment content as a pulse. An analog switch circuit 8 controls the gate based on the content and the current of the circuit 3 so as to give a level change in response to the input level fluctuation of the pilot signal. Thus, a constant level is obtained always as the output level. |
