Low cost high-speed test data acquisition: Accurate period estimation driven signal reconstruction using incoherent subsampling

In this paper, we propose a new algorithm to estimate the fundamental period (frequency) of a highspeed pseudo random bit sequence (PRBS) or multitone signal using incoherent subsampling. While incoherent subsampling suffers from spectral leakage due to the mismatch between the input test signal and the discrete Fourier transform (DFT) basis, the proposed algorithm efficiently resolves the spectral leakage problem using a back-end signal process. The approach requires incoherent digitization of the periodic sequence using at least two clocks running at different speeds. No additional hardware to synchronize the input signal frequency with the sampling clock frequency is needed. A new discrete frequency shifting approach for determining the period of the input signal is proposed that is computationally efficient. The signal reconstruction approach has been tested with experimental results.