Measurement and Data Correction of Channel Sampling Timing Walk-Off of Photonic Analog-to-Digital Converter in Signal Recovery

Abstract

A two-channel, time–wavelength interleaved photonic analog-to-digital converter (PADC) system with a sampling rate of 10.4 GSa/s was established, and a concise method for measuring and data correcting the channel sampling timing walk-off of PADCs for signal recovery was proposed. The measurements show that for the two RF signals of f1 = 100 MHz and f2 = 200 MHz, the channel sampling timing walk-off was 12 sampling periods, which results in an ENOB = −0.1051 bits for the 100 MHz directly synthesized signal, while the ENOB improved up to 4.0136 bits using shift synthesis. In addition, the peak limit method (PLM) and normalization processing were introduced to reduce the impacts of signal peak jitter and power inconsistency between two channels, which further improve the ENOB of the 100 MHz signal up to 4.5668 bits. All signals were analyzed and discussed in both time and frequency domains. The 21.1 GHz signal was also collected and converted using the established two-channel PADC system with the data correction method, combining the PLM, normalization, and shift synthesis, showing that the ENOB increased from the initial −0.9181 to 4.1913 bits, which demonstrates that our method can be effectively used for signal recovery in channel-interleaved PADCs.

A Method of Reducing Errors Due to Sampling in the Measurement of Electric Power

“…Rigorous identity between the components on each phase is not required, as a software calibration of the entire assembly can be performed in the first phase. The calibration consists in finding weighting coefficients for each size, so that the displayed value corresponds to the measured value [9][10][11][12][13].…”

“…Any method to approximate the signal variation between two successive samples could be used (polynomial, logarithmic, etc. ), but due to the small distance between the samples and the ease of calculation, the linear approximation was chosen [9][10][11]. Of course, other sequences of the quantities of interest can be used, but in order to have close voltage and current on each phase, this arrangement was preferred [17].…”

“…Any method to approximate the signal variation between two successive samples could be used (polynomial, logarithmic, etc. ), but due to the small distance between the samples and the ease of calculation, the linear approximation was chosen [9][10][11].…”

“…Considering that the signal variations were linear between two successive moments, it is proposed to determine the studied values at the same moment in time by interpolation/extrapolation, obtaining intermediate values, with the necessary changes at the ends of the acquired value vectors. [ [9][10][11].…”