AC negative feedback analysis of OCL power amplifier

The AC negative feedback of the circuit is composed of R"R and island (Figure 1-30). Since C3 can be regarded as a short circuit to AC,
the actual effect is shown in Figure 1-32. It is a voltage series negative feedback. AC Negative feedback determines the gain of the amplifier circuit
(the amplification factor of the circuit) o ​​Its calculation method is:
    K v= (1+ R7)/R6
    The gain of the amplifier circuit also determines the sensitivity of the circuit. The meaning of the sensitivity S of the circuit is:
The input voltage value required
to reach the rated output power without distortion is determined by the voltage amplification factor of the circuit. The calculation method is: assuming the rated output power is P., then the voltage at the rated output power vo=/watt meter L, circuit sensitivity s=
V o/Ku.
    In general, adjusting the circuit gain is done by changing the resistance
of R7, so some circuits design R7 as an adjustable resistor. It is worth noting here that after the resistance of R7 changes, the resistance of R2 should also
change accordingly, so that R2 = R7. This can maintain the circuit symmetry of the differential amplifier stage and improve the stability of the circuit.