Time-to-digital converter with multiple working modes

Abstract

The embodiment of the invention provides a time-to-digital converter with multiple working modes, a working mode selection module is used for processing the input time signal, so that the input time signal is distributed to a time quantification module, and multiple types of detection functions are completed in combination with a multi-channel structure; meanwhile, the time quantification module selects the reference clock from the multi-phase clocks at the respective channels based on the gating signal, thereby avoiding the time sequence constraint which is difficult to satisfy and is introduced by directly inputting the reference clock signal into each channel in a conventional scheme, achieving the localization of the time sequence, enabling the first two stages of quantification time sequences of each time quantification module to be synchronous, therefore, system errors which cannot be eliminated in a traditional time-to-digital converter scheme are converted into fixed deviationswhich can be eliminated at the same time, and the measurement precision and the measurement reliability are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of laser radar optical signal receiver systems, and relates to a time-to-digital converter with multiple working modes. Background technique [0002] Lidar ranging is a commonly used ranging technology. Its working principle is: when the laser emitter emits laser light on the target object to be detected, the laser echo reflected by the target object works in a linear mode. The avalanche photodiode receives and converts it into a current signal, and then the pulse current generated by the avalanche photodiode is linearly converted into a voltage signal by the front-end analog receiver, and then the time-to-digital converter is used to obtain the time-of-flight information of the pulse, so the time-digital The measurement accuracy, detection efficiency, and response time of the converter (TDC) put forward extremely high requirements. [0003] like figure 1 As shown, in the traditional solution, the TDC is c...

AI Technical Summary

Problems solved by technology

When the rising edge of the collected signal is very close to the rising edge of the clock, and the time interval between the two is less than the D flip-flop setup time, the first flip count will start at the second valid reference clock rising edge after the rising edge of the start signal , causing the quantization result of the counter to differ from the actual one by approximately one reference clock period; the reference Figure 3b , the interpolation quantization unit of traditional TDC and the third-level fine quantization unit are collected by D flip-flop. The input impedance of D flip-flop will change with the level of the input signal, and the propagation delay of the delay chain will also change accordingly. , the misalignment error that causes the uneven distribution of the interpolated signal is as Figure 3b shown

[0007] In summary, traditional time-to-digital converters have unavoidable system errors and cannot meet the actual measurement needs of LiDAR

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