| 摘要 |
PROBLEM TO BE SOLVED: To provide a television broadcast retransmission apparatus capable of performing AGC operations to a high frequency input having a wide dynamic range with low noise and low distortion. SOLUTION: A branching filter 32 of each of reception units 12a to 12n branches part of an output signal of an IF amplifier 31 and the branched signal is given to an MPU 35 via an AGC detector 34. The MPU 35 generates an AGC control signal AGC-1 applied to an RF amplifier section and an AGC control signal AGC-2 applied to an IF amplifier section to adjust the attenuation of attenuators 23, 27 on the basis of a signal detected by the AGC detector 34. In this case, the MPU 35 keeps the AGC-1 to a prescribed value and changes the AGC-2 in response to an RF signal level when the RF signal is equal to a setting level or below. Moreover, when the RF signal is greater than the setting level, the MPU 35 changes the AGC-1 in response to the level of the RF signal and keeps the AGC-2 to a constant value. COPYRIGHT: (C)2006,JPO&NCIPI |
