Fully Digital Feedforward Background Calibration of Clock Skews for Sub-Sampling TIADCs Using the Polyphase Decomposition

This paper presents an all-digital calibration technique for timeinterleaved ADC (TIADC) timing mismatch. The calibration architecture is based on a channel multiplexing architecture. For a M-channel TIADC, only one centralized calibration module is needed. Timing mismatches between channels are estimated by correlating the adjacent channel's outputs and a compensation algorithm based on the one-order five-point differentiator is employed to suppress the mismatches. Compared with conventional parallel calibration architecture, the proposed calibration architecture works well in higher Nyquist bands (NB) with high-scalability. The hardware consumption does not increase linearly with the number of sub-ADCs.

“…Most of the timing mismatch calibration techniques for TIADC [7,12,14,16,21,22] using parallel timing mismatch calibration structure is shown in Fig. 1(a).…”

Section: Channel Multiplexing Architecturementioning

confidence: 99%

Section: Channel Multiplexing Architecturementioning

confidence: 99%

See 1 more Smart Citation

A channel multiplexing digital calibration technique for timing mismatch of time-interleaved ADCs

Yin

Liu

Chen

et al. 2019

“…Many techniques have been developed in digital domain for timing mismatch calibration. Most of these leading methods for error estimation are featured by using channel cross-correlation [21,22,23] or introducing reference channel [24,25,26], while most of the compensation methods are based on Taylor expansion [27,28,29] or filter [30]. Most of the calibration methods mentioned above use dividers, multipliers, and differentiators, which consumed high hardware and large power.…”

Section: Introductionmentioning

confidence: 99%

Calibration of timing mismatch in TIADC based on monotonicity detecting of sampled data

Yin

Sun

Chen

et al. 2020

In this paper, a calibration method aiming at the timing mismatch existing in the TIADC (Time-Interleaved Analog-to-Digital Converter) is proposed. Monotonicity detecting of the sampled data is employed to estimate the mismatch error, in which only additive operation is involved. Besides that, an improved Taylor expansion method is used to compensate the mismatch error. The processes of the estimation and the compensation are designed to constitute an adaptive loop, so that the calibration can be run in real-time. Compared with other approaches, this method consumes less hardware resources and has a good calibration result.

“…In TIADC systems, channel mismatches seriously degrade the signalto-noise and distortion ratio (SNDR) and spurious-free dynamic range (SFDR) [18,19,20,21,22,23,24,25,26,27,28,29]. In published literature, studies of TIADC are based on the effects of channel mismatches on the spectrum or dynamic performance such as SNDR and SFDR [14,16,17,18,19,20,21,22,23,24,25,26,27,29,30,31,32]. Under the condition of large bandwidth, it is impossible to eliminate channel mismatches completely.…”

Section: Introductionmentioning

confidence: 99%

Analysis of TIADC channel mismatch effects on high-resolution range profile

Xiao

Zhang

2020

The wideband echo signals of the imaging radar can be processed by pulse compression to obtain high-resolution range profile (HRRP). The resolution of HRRP is proportional to the signal bandwidth. The pursuit of high resolution makes the bandwidth of radar transmitting signal larger and larger. And the corresponding sampling rate of receiver becomes so high that analog-to-digital conversion cannot be realized by a single chip correctly. Time-interleaved analog-to-digital converter (TIADC) technique increases sampling rate of radar receiver, but channel mismatches are brought in. Channel mismatches significantly deteriorate the dynamic performance of radar receiver. Effects of channel mismatch on SNR, SNDR and SFDR are studied in previous literatures. Derivation and simulation of TIADC channel mismatch effecting on HRRP are performed in this letter. Simulation results show that without considering the amplitude-frequency distortion and phase-frequency distortions of the radar system, when the gain mismatch is less than 0.7 times and the clock mismatch is less than 0.25 rad, the influence of the channel mismatch on the HRRP can be neglected. The results provide a reference for system design and compensation method, which are useful for the designer to determine whether complex channel mismatch calibration is necessary under specific application background.