Digital spectra of nonuniformly sampled signals: theories and applications-measuring clock/aperture jitter of an A/D system

Theories and applications of a digital spectrum analysis technique for a class of nonuniformly sampled signals are described. A method based on asynchronous spectral averaging is presented to measure the standard deviation of a clock/aperture jitter of an A/D (analog/digital) system. A sine wave with frequency f₀ is used as the input test signal to an A/D system. Spectral averaging is performed on many asynchronously acquired data records with length N. The jitter standard deviation is calculated from the measured signal-to-noise (S/N) floor ratio. The expression which relates the S/N to the standard deviation, σ_r, of the jitter, r, is derived in closed form. Graphs showing good agreement between the theoretical equation and the simulation results are presented