Technique to improve the performance of time-interleaved a-d converters

Abstract

Interleaving is one method of configuring a high-speed waveform digitizer. It is known that, in this method, using multiple A-D converters (ADC) enables sampling at a rate higher than the sampling rate of the ADC being used. Degradation of the dynamic range, however, results from such factors as phase error in the sampling clock applied to the ADC, and mismatched frequency characteristics among the individual ADCs. This paper describes a method for correcting these mismatches using a digital signal processing (DSP) technique. This method does not require any additional hardware; good correction and improved accuracy can be obtained simply by adding a little to the computing overhead.

Timing skew compensation technique using digital filter with novel linear phase condition

“…We present here its frequency domain compensation method based on [6], [7]. We design and apply a digital filter for the timing skew compensation so that spurious due to the timing skew is cancelled.…”

“…The digital filter given by (6), (7) has the linear filter characteristics, and its group delay is τ.…”

“…Suppose that the clocks CK1, CK2, Fig.7) [4][5][6][7]. If the input signal Vin(t) is sampled at time t+dt instead of time t, we have the sampling time error e(t) : e(t) = Vin(t+dt) -Vin (t) which can be approximated by…”

Calibration of channel mismatch in time-interleaved real-time digital oscilloscopes

“…Recently lots of research has been reported for the calibration of the frequency response mismatch [5][6][7][8]. Most of these works are concerned with calibrating the channel mismatch by applying FIR type filters on each channel.…”

A Compensation Method for Magnitude Response Mismatches in Two-channel Time-interleaved Analog-to-Digital Converters

“…The author in [8] shows a method to compensate frequency-dependent mismatches based on a discrete Fourier transform (DFT). This approach is limited to a finite number of samples due to the DFT calculation and it is not shown how to extend this method to continuous processing of samples.…”