Detailed analysis of a phase ADC

Banerjee, Budhaditya; Enz, Christian; Roux, Erwan Le

doi:10.1109/iscas.2010.5537552

Cited by 5 publications

(1 citation statement)

References 2 publications

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“…PhADCs based on a zero-crossing conversion algorithm have been realized in silicon by a resistor-bridge-based approach [5], [6] as well as a current-mirror-based approach [7], [8]. The benefits of robustness to circuit nonidealities and noise and large amplitude dynamic range of the resistor-bridge-based zero-crossing (ZC) PhADC has been addressed in [9]. Moreover, an IQ-assisted algorithm has recently been proposed and implemented in a charge-redistribution PhADC, resulting in a very energy-efficient PhADC topology [10].…”

Section: Introductionmentioning

confidence: 99%

A Comparative Analysis of Phase-Domain ADC and Amplitude-Domain IQ ADC

Liu

Lotfi

et al. 2015

IEEE Trans. Circuits Syst. I

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A phase-domain analog-to-digital converter (PhADC) is a promising alternative to a pair of amplitude-domain in-phase and quadrature (IQ) ADCs for low power FSK/PSK demodulation, but the fundamental benefits and limitations of the PhADC over the IQ ADC have not been precisely quantified as yet. In this paper, analytical methods are proposed to comprehensively compare the PhADC and the IQ ADC. Phase signal-to-noise ratio (SNR) expressions of the two ADC types are formulated analytically to facilitate a quantitative comparison of them. In comparison with the IQ ADC, the PhADC is a more compact quantization and demodulation solution when interference accommodation is not required. Moreover, considering a flash ADC as an example of the low resolution (3-4 bit) IQ ADC, the PhADC has a lower theoretical energy limit than the flash ADC for a given phase ENOB. IQ offsets and amplitude mismatch impose unique nonlinearities on the PhADC due to the nonlinear amplitude-to-phase conversion. The understanding of this nonlinearity leads to a phase-domain mismatch and offset detection technique. Phase SNR is explicitly related to input noise for both ADCs, and to comparator offsets for the PhADC, respectively. All of the results prove that the PhADC is a promising quantization and demodulation solution.Index Terms-Amplitude mismatch, in-phase and quadrature (IQ) ADC, offset, phase-domain analog-to-digital converter (PhADC), phase nonlinearity, phase signal-to-noise ratio (SNR).

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