Correction method and device for avoiding metastable state of time-to-digital converter of laser radar

Abstract

The invention discloses a correction method and device for avoiding metastable state of a time-to-digital converter of a laser radar. The method comprises the following steps: S1, generating a detection clock signal by using a trigger, wherein the detection clock signal and a first group of coarse count values have the same phase; S2, opening a correction mode, and gating the detection clock signal through a second multiplexer; S3, sampling the detection clock signal by using a fine counter and a phase decoder to obtain a fine count value of the detection clock signal; outputting the current fine count value of the detected clock signal to the digital judgment logic unit to be compared with the reference value, and when the current fine count value is unequal to the reference value, selecting the clock signal of the next phase to enter the next stage; and S4, repeating the step S3 until the current fine count value of the detected clock signal is equal to the reference value, and completing correction.

Description

technical field [0001] The invention relates to the technical field of laser radar ranging, in particular to a correction method and a correction device for a time-to-digital converter of a laser radar to avoid a metastable state. Background technique [0002] The statements in this section only provide background information related to the present disclosure and may not constitute prior art. [0003] In the lidar ranging system, in order to obtain ranging accuracy at the picosecond level, a multi-stage ring oscillator (Multi-phase generator) is usually used to generate a clock with multiple phases, and one clock cycle is a rough count value (such as figure 1 CTDC in <n:0>), subdivide a clock cycle into multiple equal parts, and the resulting count value is called the fine count value (such as figure 1 FTDC in <p:0>). In order to maintain the monotonicity of ranging, when the CTDC value of the coarse counter increases by one bit, the FTDC fine count value of...

AI Technical Summary

Problems solved by technology

In order to maintain the monotonicity of ranging, when the CTDC value of the coarse counter increases by one bit, the FTDC fine count value of the fine counter must jump from the highest bit (2^(P+1)-1) to the lowest bit (0), A metastable state often occurs (the laser return signal falls on the transition edge of CTDC), which leads to ranging errors

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