All-digital calibration structure based on TIADC composite output and calibration method thereof

Abstract

The invention discloses an all-digital calibration structure based on TIADC composite output and a calibration method thereof. The all-digital calibration structure comprises a data composite module, an error compensation module and an error estimation module. The data composite module performs data conversion processing on an externally input analog signal x to obtain an output signal of m channels sampled for the nth time; the error compensation module derives the composite output signal y (n) to obtain a derivative value y '(n), performs error compensation on the composite output signal y (n) according to an offset error estimation value, a gain error estimation value and a time error estimation value of (n-m) th sampling fed back by the error estimation module to obtain a compensation output signal, and transmits the compensation output signal to the error estimation module; Meanwhile, the output is used as the final output of the TIADC in the n sampling. According to the invention, TIADC system calibration suitable for any channel can be completed with low hardware consumption, so that signals of any Nyquist frequency band can be calibrated, and mismatch errors can be efficiently compensated.

Description

technical field [0001] The invention relates to the field of analog-to-digital conversion, more specifically to an all-digital calibration structure and calibration method for mismatch errors between channels of a multi-channel time-interleaved analog-to-digital converter. Background technique [0002] With the rapid development of social information technology, the performance requirements of analog-to-digital converters (Analog-to-digital) in the fields of communication, computer, and instrument control are getting higher and higher, so high-performance ADCs have a very wide range of applications, and has important strategic significance. Limited by the current level of ADC development and technology, the performance of a single ADC is difficult to meet the requirements of high speed and high precision at the same time, so the time-interleaved analog-to-digital converter (TIADC) came into being. [0003] TIADC (Time-Interleaved Analog-to-Digital Converter) is a parallel a...

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Problems solved by technology

S.Jamal and D.Fu proposed to calibrate offset mismatch based on random chopping, and calibrate gain mismatch and sampling time mismatch based on chopping modulation (Jamal Shafiq M, Fu Daihong, Hurst Paul J, Lewis Stephen H.A 10-b 120-Msample / stime-interleaved analog-to-digital converter with digital backgroundcalibration[J].IEEE Journal of Solid-State Circuits,v 37,n 12,p 1618-1627,December 2002), however this The solution is only applicable to two-channel TIADC, and cannot be expanded to more channels or even any channel

Matsuno J, Yamaji T and Furuta M proposed a method based on Walsh function modulation transform to construct the signal related to the spurious signal for error estimation and compensation to calibrate the gain and time error (Matsuno J, Yamaji T, FurutaM, et al .All-Digital Background Calibration Technique for Time-InterleavedADCUsing PseudoAliasing Signal[J].IEEE Transactions on Circuits&Systems IRegular Papers,2013,60(5):1113-1121.), however, this scheme is only applicable to TIADC with an even number of channels, And the offset error must be calibrated independently first. The more the number of channels, the more modulation functions need to be used, and the hardware consumption will increase exponentially.

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