NEGATIVE FEEDBACK AMPLIFYING DEVICE AND NEGATIVE FEEDBACK AMPLIFICATION TRANSMISSION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a negative feedback amplifying device with stability and small distortion to a variance of transmission bandwidth and environmental variations. SOLUTION: A modulation means 3 for modulating an input signal through a carrier signal; an amplifier means 4 for amplifying the modulation signal modulated by the modulation means 3; a demodulation means 5 for demodulating the output signal of the amplifier means; a subtraction means 6 for subtracting the output signal of the demodulation means from a modulating signal; a filter means 7 with variable cut-off frequency for outputting a feed-back signal by performing band confinement of the differential signal; a summing means 2 for adding the feed-back signal to the modulating signal and entering it to the modulation means; and a filter coefficient control means 10 for controlling the cut-off frequency of the filter means according to the magnitude of the differential signal are provided. In addition, the filter coefficient control means can change the cut-off frequency of a loop filter. COPYRIGHT: (C)2007,JPO&INPIT