| 摘要 |
PROBLEM TO BE SOLVED: To avoid a mutual influence on terminals whose in-use frequency bands overlap with each other in a large-scale PLC system, and to improve tolerance to large-amplitude noise etc., to secure stabler data communication. SOLUTION: TIMGSW 96 which performs gain control over a signal on a frequency axis includes a square circuit 131 which squares a signal on the frequency axis, a power integrating circuit 132 which integrates the squared power signal from the square circuit 131, a zero counter 133 which counts 0's of high-order bits of the square-sum power signal from the power integrating circuit 132, a low-order bit extracting circuit 135 which extracts values of a necessary number of bits from the low-order bits of the square-sum power signal, a bit selector 134 which performs gain control by performing logarithmic linear level detection on the signal on the frequency axis based upon the count value of the zero counter, and a conversion ROM 136 and a multiplier 137 which perform fine adjustment of a gain for the signal from the bit selector 134 based upon the count value and the extracted value of the low-order bit extracting circuit 135. COPYRIGHT: (C)2010,JPO&INPIT
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