| 摘要 |
PROBLEM TO BE SOLVED: To surely suppress an excessive output occurring when an input signal is reset from instantaneous power interruption. SOLUTION: Output level of a power amplifier 12 for amplifying an input signal is detected by a first detector 13 and an input signal of the power amplifier 12 is attenuated by a variolosser 11 to have a rated level. On the other hand, output level of the power amplifier 12 is detected by a second detector 18 and detection output is delayed by a predetermined time through a delay circuit 19. Signal levels before and after delay are compared by a comparison circuit 20 and output from the power amplifier 12 is passed selectively through an attenuator 17 based on the comparison results and attenuated. Since output level is suppressed by the attenuator 17 in the AGC circuit during a period immediately after instantaneous power interruption before settling of power amplification output at the output stage, excessive peak power is not delivered immediately after resetting from instantaneous power interruption and power level of the output signal can be suppressed surely to a rated level or below. COPYRIGHT: (C)2006,JPO&NCIPI
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