| 摘要 |
PROBLEM TO BE SOLVED: To drastically reduce the circuit scale of an analog part by performing digital processing of adjustment of input signal for width and a bridge tap by software in an LSI. SOLUTION: In this equalizing circuit 30, an analog signal processing part consists of a transformer 33, a variable attenuation amplifier 35, a buffer 37 and variable amplifier 39, and a digital signal processing part consists of an A/D converter 43 accomplished by software in an LSI part 41, a 1st ROF(roll-off filter) 45, an HPF(highpass filter) 47, an RS(resampling) 49, a 2nd ROF 51, an ADF(adaptive digital filter) 53, a ROM 55 and a PEK (peak detect) 57. The attenuation of the amplifier 35 and the gain of the amplifier 39 are controlled by a variable control signal supplied from the part 41. The PEK 57 detects a peak value of an output of the HPE 47, supplies it as a variable control signal to the amplifiers 35 and 39 and also supplies it to the ROM 55 to decide the initial value of a root (f) characteristics.
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