Behavioral test benches for digital clock and data recovery circuits using Verilog-A

This paper presents the behavioral implementation of jitter tolerance test benches for digital clock and data recovery circuits using Verilog-A. First, we encode a variable-length pseudo-random bit sequence (PRBS) generator. Such circuits are widely used to generate test data for a variety of circuits and systems. Using this PRBS generator, we set up a test bench for the evaluation of jitter tolerance. A novel simulation methodology is described that modulates the amplitude and frequency of the jitter sinusoid iteratively to find the jitter tolerance. We conclude with a comparison of jitter tolerance simulation results, computed using various PRBS lengths, for the data recovery circuit under test