Programmable gain amplifier circuit diagram

This circuit is a programmable gain amplifier with differential input . 5G4051 is equivalent to a single-pole eight-throw switch. When pin 6 is low level, it corresponds to a state of A, B, and C. When the channel is turned on, it changes by one, so that the feedback resistance changes once, correspondingly The voltage gain changes one value. The status of the two 5G4051s changes synchronously, and the output voltage is differentially amplified by F007.