ADAPTIVE NOISE CANCELLATION BASED ARCHITECTURE FOR CORRECTION OF GAIN AND OFFSET MISMATCH ERRORS IN TIME-INTERLEAVED ADC

Abstract

Analog-to-Digital Converters (ADCs) represent a main bottleneck for realizing highspeedtelecommunication systems such as cognitive radio and Software-Defined Radio (SDR)systems in addition to various requirements of transmission quality. Time-interleaved A-Dconverter (TI-ADC) may be considered as an effective candidate to achieve high-speed ADC withrelatively slow circuits accounting for digital spectrum management. However, mismatch errorscause a considerable degradation in the performance of TI-ADC. In this paper an adaptivecompensation technique is proposed for improving the overall performance in presence of offsetand gain mismatches. The proposed structure behaves independent from input signal. Here, Least-Mean-Squares (LMS) algorithm has been exploited to adaptively estimate and correct mismatcherrors. The Proposed correction method is structurally very simple and hence suitable forimplementation on integrated circuits. Besides, proposed digital compensation algorithm iscomputationally efficient. Considering a four-channel TI-ADC, the proposed compensated TIADCprovides an approximate improvement of 33.2dB in the performance compared touncompensated architecture. The proposed compensated TI-ADC would be an efficient high speedADC in most RF communication applications, and especially applications that deal with tunedfrequency.