VARIABLE GAIN CONTROL CIRCUIT USED PULSE WIDTH MODULATION SIGNAL

摘要

gain control signal-controlled switching device, an operational amplifier which has the 2nd input port that receives input signal; and the 1st input port that is connected to a ground port through the upper swiching device; a low pass filter which low-pass filters the output of op-amp. In particular, this characterizes a variable gain control circuit which enables the gain varied by controlling the switching period of switching device.