Multifunctional phase sensitive detection circuit

Filter 18.432M

The phase sensitive detection circuit (cooperating with the filter) can reduce the amplitude modulation wave to the original signal waveform and function as a demodulation; and has the ability to discriminate the phase of the signal. A typical diode phase sensitive detection circuit and its input-output relationship diagram are given below. It consists of four diodes D1 to D4 with the same characteristics connected in series in the same direction to form a bridge circuit with additional resistors on the bridge arm for bridge balance. The four terminals are respectively connected to the secondary coils of transformers A and B. The input of transformer A is amplitude modulation wave xm(t), the input signal of B is carrier y(t), and uf is output. The conduction and turn-off of the diode is completely determined by the output of the secondary of B, so the output of the secondary of B is required to be greater than the secondary output of A.