A DC restoration method and device for an AC signal

Abstract

The invention provides a direct current recovery method and a direct current recovery device of an alternating current signal. The method comprises the steps as follows: firstly, a control circuit determines a reference potential; then an input end inputs the alternating current signal, a first capacitor stores a first direct current component, and enables a first alternating current to pass through; then the control circuit compares the input first alternating current component with the reference potential, and sends a first control signal to a switch to close the switch, when judging that the lowest potential of the first alternating current component within a current period is less than the reference potential; then a direct current power source charges the first capacitor when the switch is closed, thus enabling voltages at two ends of the first capacitor to reach a first preset value; and then an output end outputs the first alternating current component and a second direct current component. Therefore, the output direct current component can be stabilized at the second direct current component value, and the problem that at present, the direct current component of the video signal is instable, and thus the brightness of the image is seriously distorted is effectively solved.

Description

technical field [0001] The invention relates to the field of integrated circuit design, in particular to a DC restoration method and device for AC signals. Background technique [0002] In analog signals, there are AC components and DC components. The DC component contained in the video signal usually changes with the brightness of the video signal. The input stage of the video acquisition system is mostly an analog-to-digital converter powered by a single power supply or a single-ended or differential operational amplifier, which generally can only process signals with a potential within 0V to the power supply voltage. Since the DC component of the signal source is unknown, it needs to be blocked and attenuated by a capacitor before entering the amplification circuit or analog-to-digital converter. When the signal is blocked by capacitance, the coupling capacitor stores the sum of the average value of the signal, and the signal originates from the DC voltage difference be...

AI Technical Summary

Problems solved by technology

[0004] Therefore, it is necessary to provide a technical solution for DC recovery of AC signals to solve the problems of complex logic circuit design, high hardware cost, serious signal waveform distortion, and inability to conveniently set reference potentials in existing DC signal recovery methods.

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