High-speed analog-to-digital conversion method and circuit device thereof in TDR (Time Domain Reflector)

Abstract

The invention relates to an implementation method of high-speed analog-to-digital conversion in a TDR (Time Domain Reflector). The implementation method is used for realizing super-speed equivalent sampling of an analog-to-digital converter through emitting the same step pulse and adopting a method that a phase difference between the step pulse used as a testing signal and the sampling pulse with the same frequency as that of the step pulse of the analog-to-digital converter is periodically, linearly and progressively increased. The periodic, linear and progressive increase of the phase difference between the step pulse and the sampling pulse is achieved by a phase-locked loop. A high-speed analog-to-digital conversion device in the TDR, which is formed by using the implementation method, is characterized by comprising a phase discriminator, a loop filter, a voltage-controlled oscillator, a step pulse generator, an analog-to-digital converter, a microcontroller, a digital-to-analog converter and a crystal oscillator. The high-speed analog-to-digital conversion circuit device in the TDR, disclosed by the invention, realizes ultrahigh-speed and high-precision analog-to-digital conversion by using the lower-speed and high-precision analog-to-digital converter, meets the requirements on resolution ratio of testing characteristic impedance discontinuity and precision of impedance data and reduces the requirements on speeds of a controller and a buffer memory simultaneously.

Description

technical field [0001] The invention relates to the technical field of electronic testing, in particular to a method for high-speed analog-to-digital conversion in TDR and a circuit device thereof. Background technique [0002] A typical TDR (Time Domain Reflector) characteristic impedance test system is mainly composed of a high-speed step pulse generator and a high-speed analog-to-digital converter. The rise time of the step pulse determines the ability to distinguish the discontinuity of the characteristic impedance; the high-speed analog-to-digital converter determines the test time, that is, the resolution of the change position of the characteristic impedance. [0003] Assuming that the transmission speed of the step pulse signal on the printed circuit is 150m / us, if the position accuracy of the characteristic impedance change is required to be 5mm, the minimum unit of time measurement should be 33.3ps, that is, the sampling frequency of the analog-to-digital converter...

AI Technical Summary

Problems solved by technology

But there is no ultra-high-speed, high-precision analog-to-digital converter and corresponding speed controller and buffer memory that meet such requirements.

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