Double-constant current source structure-based high-resolution fast time interval measurement circuit

Abstract

The invention discloses a double-constant current source structure-based high-resolution fast time interval measurement circuit. Based on a time-to-amplitude converter, a double-constant current source structure composed of a discharging constant current source and a charging constant current source is adopted, and a charging and discharging capacitor is charged through the charging constant current source, so that the voltage of the charging and discharging capacitor can return to initial voltage. According to the double-constant current source structure-based high-resolution fast time interval measurement circuit of the invention, the charging constant current source has two kinds of working states; and under the control of on-off control signals, the magnitude of the charging current of the charging constant current source can be changed, namely, the charging constant current source optionally generates micro current according to measuring process requirements in an initial preparation measuring phase, a discharging phase and an ADC sampling stage, and so as to provide stable initial voltage for the charging and discharging capacitor in the initial preparation measuring phase, and after measurement is completed, the charging constant current source optionally generates high current to charge the charging and discharging capacitor, so that the voltage of the charging and discharging capacitor can be restored rapidly, and therefore, time interval measurement speed can be improved. With the double-constant current source structure-based high-resolution fast time interval measurement circuit adopted, the time interval measurement speed can be improved greatly with measurement accuracy ensured, and therefore, random equivalent sampling waveform reconstruction efficiency can be further improved.

Description

technical field [0001] The invention belongs to the technical field of time interval measurement, and more specifically relates to a high-resolution fast time interval measurement circuit based on a double constant current source structure. Background technique [0002] In a random sampling oscilloscope, the processor reorders the waveforms acquired by multiple triggers according to the positions of the trigger points, so as to realize the reconstruction of the measured waveform. The waveform reconstruction is based on the time interval ΔT between each trigger moment and the rising edge of the next data synchronization clock after the trigger, the trigger signal and data synchronization clock are sent to the time interval measurement circuit, the trigger signal and the data synchronization clock from the ADC Perform XOR to generate a narrow pulse carrying time interval information ΔT, and this time interval enters the time-to-amplitude conversion (Time-to-amplitude Converter...

AI Technical Summary

Problems solved by technology

For the RC circuit to really reach a stable state, it often takes about 5τ, that is, about 5ms, which is difficult to meet the waveform reconstruction efficiency requirements of random equivalent sampling

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