| 摘要 |
PURPOSE:To prevent the generation of a data error at reception of a burst signal by keeping an AGC voltage at signal incoming while no burst signal is incoming to provide an ideal AGC response speed. CONSTITUTION:When a burst signal is incoming from a transmission line, after frame synchronization is established by a frame synchronizing circuit 6, a control signal is generated from a control circuit 7 based on the establishment detection signal. Switches 4, 5 are turned on when the burst signal exists and the switches are turned on during other period. That is, while the burst signal is received, the detection signal detected by a peak value detector 2 flows to a time constant circuit and a DC electric charge in response thereto is stored in a capacitor C1 and the electric charge applies AGC. Since the switches 4, 5 are turned off at the period T1 until the next burst signal is incoming, the electric charge stored in the capacitor C1 is continued. The AGC response speed is quickened as if it were infinite at the incoming of the next burst signal and the AGC operation in tracking with the rapid level change of the burst signal is executed.
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