Introduction to the Frequency Doubling Circuit and Principle of Diodes and Tripods

Introduction to the Frequency Doubling Circuit and Principle of Diodes and Tripods

Principle: When the frequency is an AC signal and is input to a nonlinear component diode transistor, the original sine wave signal will generate DC, fundamental components, and second and third harmonic components. Then, through a frequency selection network, the desired frequency band can be selected to obtain the desired frequency band signal for doubling.

Diode frequency doubling circuit: When an AC signal passes through a diode, the on/off of the diode will generate new resonant frequency signals, such as higher harmonics f, 2f, 3f, etc.

When selecting 3f as the target signal, these signals together form a frequency selection circuit through C1 and T1. For the 3f signal, this circuit is equivalent to a large resistor. Therefore, the transformer at both ends of the frequency selection circuit receives a high voltage of the 3f signal, while other signals are bypassed to ground. The 3f signal on the transformer can be stepped up or down to the secondary output to the backend circuit.

Transistor frequency selection circuit: It is similar to the principle of a two-stage transistor frequency selection network. The signal first passes through a capacitor to the base of the transistor, and then amplified by the transistor before being output from the collector. By using the on-off state of the transistor, various harmonics are generated.

Then, frequency selection is carried out through a parallel resonant circuit composed of C1 and T1, selecting the required 2nd or 3rd harmonics. The primary coil of T1 forms the high voltage required for the signal, and finally outputs it to the backend circuit through the secondary coil of the transformer.