A video adc real-time correction circuit and method

Abstract

The embodiments of the invention disclose a real-time correcting circuit for a video ADC (Analog to Digital Converter). The circuit comprises an error detection and processing module, a video ADC, a video signal composite synchronous separation module, a mode control module, a first DAC (Digital to Analog Converter), a second DAC and a first selection module, wherein the video ADC is used for AD conversion of input signals; the video signal composite synchronous separation module is used for separating a row correction enabling signal and a field correction enabling signal from input composite video broadcast signals (CVBS); the mode control module is used for setting a working mode and generating a correction signal; the error detection and processing module is used for error detection and correction; and the first DAC and the second DAC are used for digital to analog conversion. By adopting the technical solution, the conversion precision of the ADC is improved, the normal data conversion process is not influenced, an additional memory is also not needed, and the power consumption and the area of an IC (Integrated Circuit) are reduced.

Description

technical field [0001] The invention relates to the field of analog-to-digital conversion of video images, in particular to the field of analog-to-digital conversion of video images which can be self-adapted and corrected in real time. Background technique [0002] The integrated circuit video ADC mainly changes the built-in DC bias and the maximum quantization range of the ADC due to the influence of the process, causing the DC characteristics of the ADC to deviate from the expected design value, resulting in an offset error of ±OFFSET, as shown in the attached figure 1 As shown, the broken line L is an ideal AD conversion line, but the broken line L1 is an AD conversion line with a positive offset (OFFSET) error, and the broken line L2 is an AD conversion characteristic curve with a negative offset (OFFSET) error. A reference voltage independent of temperature and power supply voltage is used to generate DC bias and determine the quantization reference voltage value of the...

AI Technical Summary

Problems solved by technology

However, the correction method adopted in this prior art requires an additional memory to store correction data, occupies a large system area, and increases system cost and power consumption. Although the automatic correction process is realized, it can only be corrected when the power is turned on ADC data, can not realize the interval periodic correction function, can not correct the DC offset and gain error of the ADC in real time

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