Q23, R56 and R53 * * form a simple voltage stabilizing circuit, which provides reference voltage for Schmidt circuit (hysteresis circuit). When the input signal is higher or lower than the reference voltage by a certain value (which is adjusted by R52), the Schmidt circuit will be inverted.
The comparator below just acts as an inverter to output two square waves with completely opposite phases.
Diodes are used to protect the emitter junction of Q22 and prevent the emitter junction from being broken down due to the high input voltage.
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1.Q22 What is the voltage waveform after the emitter input voltage is plus or minus 0.6V~ ~ plus or minus 50V?
The emitter output is half-wave minus 0.6V, which can be approximately regarded as half-wave.
2.Q23 is a simple voltage stabilizing circuit. After the output of hysteresis comparator is fed back to Q23 voltage stabilizing circuit through R52 and R54, will the voltage stabilizing signal of Q23 diode emitter be affected?
: R54 has two functions here: a. As an input resistor, it will minimize the influence on the previous stage; B as a feedback voltage divider, it determines the amplitude of hysteresis voltage together with R52***.
In addition, the simple voltage stabilizing circuit uses the transmitter output, the output impedance is relatively small, and the feedback of the later stage should have little influence on it. Moreover, the influence of hysteresis circuit on reference point is to produce positive feedback.
Since we talk about the influence of simple voltage stabilizing circuit, we have to say that the resistance value of R53 is too large, which will cause the output impedance to be too large, which will be greatly affected by the later period. Therefore, it seems appropriate to reduce it. 5 10 ohm is not small.