Comparator-based high-precision edge detection method and system

Abstract

The invention provides a high-precision edge detection method and system based on a comparator. The method comprises the following steps: acquiring a to-be-detected waveform output by a detected device, pre-estimating a low level value and a high level value, setting an initial level, and taking the initial level as a threshold level; inputting the waveform to be measured and the threshold level into a comparator, comparing the threshold level with the waveform to be measured, and outputting a comparison signal; judging whether the comparison signal meets a preset condition or not, if not, iteratively adjusting the threshold level with a preset step length for re-comparison until the comparison signal meets the preset condition, and taking the threshold level meeting the preset condition as an output level; and obtaining an actual low level value and an actual high level value of the to-be-detected waveform, and calculating and setting a judgment level to carry out edge detection. According to the invention, the influence of the resistance error and the level error on the edge detection precision can be eliminated without the help of other measuring equipment, and the edge detection precision is effectively improved.

Description

technical field [0001] The invention relates to the field of edge detection, in particular to a comparator-based high-precision edge detection method and system. Background technique [0002] The edge test is to measure the rising edge and falling edge of the signal, and then obtain the rising and falling time of the test signal level conversion, which is a standard test of ATE equipment. [0003] Edge detection is tested based on the relative amplitude of the rise / fall of a specific signal, as shown in the attached manual figure 1 As shown, when the signal rises from a low level to a high level, the amplitude difference between the high and low levels is H, and generally the time difference between the signal rises 0.2H and 0.8H is used as the rise time Tr (20-80); similarly, The falling time Tf can be defined; Tr(10-90) / Tf(10-90) can also be defined by 0.1H and 0.9H, and different ratios can be adopted in different situations. [0004] Large instruments generally use hig...

AI Technical Summary

Problems solved by technology

Assuming that the rising edge is a straight line, Vt=0, the deviation of the resistance changes the level amplitude, but the rising time does not change, resulting in T2=A*T1; the error reaches (A-1)%

[0012] Therefore, there are two main influencing factors in traditional edge detection, level error and resistance error.

In the actual ATE equipment, the existing technology can only calibrate the level error, but it is difficult to calibrate the resistance error (considering the actual scene, the link and the device under test cannot be predicted, it can be considered that Rs and Rw cannot be calibrated), So the error cannot be eliminated by calibration

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