Abstract: A new method for short time interval measurement based on the delay line principle is presented. By utilizing a group of delay lines to generate multi-path reference frequency signals delayed uniformly in a reference frequency period, then counting them under the same gate generated by the short time interval, with the average as the count of the reference frequency, the measurement error can be reduced by 1~2 orders of magnitude. Error analysis shows that its accuracy is determined by the delay time of the delay unit. Actual measurement data show that when the reference frequency is 200MHz, the delay time of the delay unit is 500ps, its accuracy is better than 500ps and improved by 10 times compared with the pulse-filling measurement method under the same condition. Compared with the analog interpolating, time-to-voltage conversion and time vernier method, the proposed new method has the characteristic of easy implementation, low cost and high feasibility.

Key words: time measurement, delay line, gate time, error analysis, pulse-filling method