| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic gain control amplifier capable of outputting a valid signal at a proper level. SOLUTION: A level measurement section 14 periodically measures a signal level LVL of an input signal SI and a signal discrimination section 15 divides the measured level into a voice level VOI and a noise level NOI. A valid number count section 16 counts the number of consecutive voice levels VOI, a level latch section 17 latches the voice level VOI and a signal level calculating section 18 accumulates the voice levels VOI. An invalid signal detection section 21, when receiving the noise level NOI, checks the number of valid consecutive counts of a register 19, when the count is one, the register 19 gives a correction signal COR to the signal level calculation section 18. The signal level calculation section 18 subtracts the voice level VOI latched in the level latch section 17 from the accumulated value of the voice level VOI. Thus, the noise component is excluded from an average signal level to calculate a correct amplification degree. COPYRIGHT: (C)2003,JPO
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