A digital spectral analysis technique and its application to radio astronomy

An efficient, digital technique for the measure ment of the autocorrelation function and power spectrum of Gaussian random signals is described. As is well known, the power spectrum of a signal can be obtained by a Fourier transformation of its autocorrelation function. This report presents an indirect method of computing the autocorrelation function of a signal having Gaussian statistics which greatly reduces the amount of digital processing that is required. A review of the measurement of power spectra through the autocorrelation function method is given. The one-bit technique of computing the autocorrelation function is presented; in partic ular, the mean and variance of the resulting spectral estimate have been investigated. These results are then applied to the problem of the measurement of spectral lines in radio astronomy. A complete radio-astronomy system is described. (Author).