The Application Of Random Equivalent Sampling In Acquisition System With 5gsps Real-Time Sampling

Due to the restriction of the Nyquist sampling theorem, the maximum frequency of underlying signal is limited. In order to extend the bandwidth of the acquisition system and realize the sampling of the periodic signal with high frequency, a random equivalent sampling approach is proposed. The key issue of the random equivalent sampling is to accurately measure the time interval between the trigger point and the next sampling clock pulse, and to determine the position of the sampled data in the signal reconstruction by the time-alignment method. This paper describes the basic principle of random equivalent sampling. Based on double oblique integral circuit, the limitation of using this scheme in 5Gsps oscilloscope is put forward and the corresponding equivalent sampling system is designed to realize 200 Gsps equivalent sampling from ADC working at real time sampling rate of 5GHz.