Channel mismatch compensation in multichannel sampling circuits with weighted integration

This paper analyses adaptive compensation of the SC channel mismatch with blind estimation. Since this compensation is performed in the digital domain, it is as accurate as the mismatch estimation. If the input signal used for the channel mismatch estimation is a stationary stochastic process, the accuracy of the estimation is proportional to the estimation time for a given type of the input signal. The requirements for the accuracy of the mismatch estimation are determined by the resolution of the analog-to-digital converter (A/D) used in the equipment. In the paper, the time necessary for the channel mismatch estimation is determined as a function of the number n of A/D bits for several types of the input signals. It has been shown that the required estimation time is proportional to (2ⁿ - 1)², for all possible probability distributions of the input signal. Thus, this time grows very fast when the number of A/D bits increases. As a result, blind channel mismatch compensation becomes problematic when the number of A/D bits exceeds 12. The required estimation time also depends on the probability distribution of the receiver input signal. Among signals used in practice, the shortest estimation time corresponds to the signals that can be approximated by the sinewave with random phase, and the longest estimation time corresponds to the signals with Gaussian distribution.