Sine wave signal generator circuit

The sinusoidal oscillator circuit consists of the following parts;
    amplification part:
the amplitude stabilization link is composed of the operational amplifier pLA741, RP, and Ri, which together with the operation
constitute the basic amplification circuit. The frequency selection network
consists of R3 Ci in series and RzG in parallel.
    Positive feedback network: It is formed by winding C across
the input and output of the amplifier. Product C. ,
Rz Cz are connected in series and parallel with the amplifier to form
a positive feedback with frequency selective characteristics.
    It can be seen from the characteristics of the frequency selection network that
the natural frequency of the network fa =l/2 ears [C (Rz -Ri=
R, cI =C2 =C). At this frequency,
the amplifier output voltage is the same as the one sent to the non-inverting input end. The voltage phase is the same, "positive feedback is satisfied, and its positive feedback coefficient F=Ui+/Uo -1/3 is the maximum.
According to the self-oscillation conditions of the sinusoidal oscillation circuit, the frequency must meet the requirements of self-oscillation. However, due to the operational amplifier The open-loop gain A
is very large, so AF=
A Distortion. In this way, the basic amplification circuit becomes an amplifier with a non-inverting input of a negative feedback network, and its A.f-
1+RRP /RRI.
  Adjusting RP changes the voltage amplification factor of the basic amplification circuit, which is balanced according to the amplitude of the sinusoidal oscillation circuit. Condition AvF F-1, it can be seen that
when AwF<l, that is, I+RRP/RR, <3, there will be no oscillation} When AwF≥l, that is, 1+RRP/RRI≥3, there will be distortion. So adjust RP
to make it When it is a certain value, it is guaranteed that Av-F is slightly greater than 1. That is, when 1+RRP/RR1≥3, the output is a sine wave,