A broad-band power spectrum analyzer based on twin-channel delayed sampling

This paper describes a power spectrum analyzer whose bandwidth is not limited by the mean sampling time. The procedure is based on the estimation of the spectral components of the autocorrelation function of the input signal through the simultaneous random sampling of the given input signal and its randomly “delayed copy.” The samples are therefore randomly taken in a double-dimension space, time, and delay. By using a random process in the time domain with a recursive mean previously introduced by the authors in order to avoid any bandwidth limitation due to the sampling strategy, it is shown both theoretically and through simulation that the estimate of the power spectral components is asymptotically unbiased on the unique hypothesis of a synchronized random sampling in the delay domain, i.e., the sampling delays are uniformly distributed in an interval equal to the period of the input signal. The simulation results confirm the theoretical findings.