1 October 2011 Clock drift-tolerant optical bit pattern monitoring technique in asynchronous undersampling system
Huixing Zhang, Wei Zhao
Author Affiliations +
Abstract
Based on an asynchronously undersampling system, we present a novel bit pattern monitoring technique in terms of its performance analysis and the implementation aspects. Relying upon an finite impulse response (FIR) filter assisted fine synchronization of the acquired samples, the technique can significantly reduce the random walk clock drift between data signal and sampling source compared to a conventional fine synchronization using a fixed time step. For the performance analysis of this technique, we first present an intuitive understanding of the principle of the FIR filter method under consideration of the filter frequency response. We find that the frequency response of the FIR filter simply serves to extract the spectral component at the aliasing frequency found in the periodogram and diminish all other frequency components. Then we test the tracking limit and discuss the optimized filter length choice of the new bit pattern monitoring technique through numerical examples. It turns out that the optimal filter length is chosen as the one which minimized the measured jitter and can be found iteratively. Finally, we present an experimental verification of this FIR bit pattern synchronization method by measuring and reconstructing bit patterns of 40 Gb/s nonreturn-to-zero and 160 Gb/s return-to-zero data signals, respectively.
©(2011) Society of Photo-Optical Instrumentation Engineers (SPIE)
Huixing Zhang and Wei Zhao "Clock drift-tolerant optical bit pattern monitoring technique in asynchronous undersampling system," Optical Engineering 50(10), 105008 (1 October 2011). https://doi.org/10.1117/1.3640828
Published: 1 October 2011
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KEYWORDS
Clocks

Finite impulse response filters

Optical filters

Electronic filtering

Eye

Digital signal processing

Data acquisition

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