Temporal resolution in information processing in an acousto-optic spectrumanalyzer with sequential readout of the information

The temporal resolving power of an acousto-optic spectrum analyzer is estim ated with allowance for the various types of distortions occurring in the i nstrument. Rapid variation of the spectrum of the input temporal signal dur ing a time shorter than the signal transit time across the cell and the: co mmutation time of the photodetector array leads to distortions that preclud e exact determination of the spectral distribution of the input signal. Len gthening the residence time tau of the signal in the cell, which increases the number of distinguishable spectral intervals, is shown to simultaneousl y decrease the usable signal duration and to degrade the temporal resolving power of a spectrum analyzer estimating the spectrum of a signal with a pe riodically varying composition. It is shown in which cases distortions that lower the resolving power can be weakened. (C) 2000 The Optical Society of America. [S1070-9762(00)00602-3].