Design and implementation of 500GSPS random equivalent sampling

With the increase in horizontal scanning speed, the time observing window narrows down, so the high random equivalent sampling rate is needed. There are two key points that determine equivalent sampling rate, namely real-time sampling rate of analog-digital converter and high resolution of time interval measurement. In this paper, a method of multichannel random equivalent sampling based on time-interleaved ADC structure is proposed. the crucial time-interval measurement circuit based on time to Amplitude was introduced and explored. Besides, a high-speed trigger channel is needed for high speed data acquire, the relationship of trigger signal and data synchronized clock was discussed, and the circuit of trigger channel was gave. The experimental data show that 500GSPS random equivalent sampling rate was obtain. The method given in the article can also be extended into wide ranges of high speed data acquisition system such as Time domain reflectometer, and jitter analyzer etc.