METHOD FOR MODELING DISPERSION ANALYZERS OF LOW-FREQUENCY SIGNAL SPECTRUM

摘要

A method for modeling dispersion analyzers of low-frequency signal spectrum involves simulation of analyzer of effective spectrum and analyzer of active spectrum with determination of effective spectrum by correlation meter. A dispersive delay line (DDL) of both analyzers has linear function of group delay time (GDT) which is simulated in Mathcad, wherein a table of parameters and zeroes of Hurwitz polynomial of DDL sections is obtained, each having one first order phase contour and specified number of second order phase contours. In the analyzer of effective spectrum, which DDL line has nonlinearly-monotone function of GDT with specified number of first order phase contours, DDL response function is multiplied by formulaor frequency correction of this response is performed by function of the same formula. Optimal number of low frequency DDL sections and number of second order phase contours of each section are determined by computer modeling in analyzers of first and second variants. In the analyzer of third variantparameter of GDT contour function and number n thereof are determined with the determination of better use of formula. In the second variant of analyzer simulating is performed in VisSim using optimization block when analyzing known (classical) concept of active spectrum, but while using new concept of active spectrum determined is an envelope functionby means of Hilbert transformation according to prescribedphase function by simulating in Mathcad, and correlation thereof withphase function is checked. Effective spectrum is determined by obtained spectral functionof that envelope, therefore autocorrelation functionis simulated in Mathcad, or in VisSim Comm autocorellation block Sliding Correlate is used.