Adaptive online calibration in time stretched ADC arrays

Abstract

It has recently been shown that photonics can be a powerful tool for manipulating the timescale of electrical signals. Stretching the signal prior to digitization has been proposed as a method to increase the effective sampling rate and the input bandwidth of the ADC, and to effect a reduction in the sampling-jitter noise. Sampling rates greater than 100Gsample/s have been demonstrated with this technique. This paper analyzes the performance of Time Stretch ADC (TSADC) arrays and proposes a novel adaptive calibration technique for mitigating the interchannel mismatch errors. The technique exploits the fact that each channel in the TSADC array is sampled at or above Nyquist rate, a key feature not shared by the conventional sample-interleaved architecture.