Estimating zero-crossings of uniformly sampled data

Analysis of the zero-crossing times of angle-modulated signals provides a computationally efficient means of implementing a number of processing functions, including demodulation and spectral estimation. Unfortunately, the sampling of a bandlimited signal is typically accomplished using uniformly spaced amplitude samples rather than detecting the zero-crossing times. The authors investigate the use of linear interpolation to estimate zero-crossing times from the uniformly sampled data. The statistical properties of the errors due to interpolation, additive Gaussian noise, and quantization are considered as functions of the sampling interval