| 摘要 |
PROBLEM TO BE SOLVED: To provide a signal amplification processor capable of changing an amplification factor under a prescribed condition even after deciding the amplification factor of a variable gain amplifier. SOLUTION: A peak detecting circuit 11 detects the maximum value of output from an A/D converter. A Pa calculation circuit 12 receives the maximum point of the output in one frame by the portion of 16 frames and calculates their average Pa. A Pa-m calculation circuit 13 outputs the maximum one among averages Pa as Pa-m. At the beginning, the Pa-m is inputted to an arithmetic part 17 and a CPU controls the amplification factor of a variable gain amplifier based on results of comparing circuits 18, 19. After deciding the amplification factor (F=1 in a flag setting part), when a first comparing circuit 14 detects the Pa larger than the Pa-m, a selector holding circuit 15A gives the Pa to the part 17, thereby convergence operation is restarted, based on the Pa to reduce the amplification factor.
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