Temporal heterodyne spectrum analysis requires the use of discrete photodetector arrays that have a large number of elements. Each element is generally followed by an amplifier, a bandpass filter, a demodulator, and nonlinear devices to handle the large dynamic range. When the number of elements in the array is of the order of 1000–2000, the readout hardware is difficult to implement. We consider decimating the array so that a much smaller number of elements are used. The spectrum is scanned across this array so that each element reads out o set of 3patial frequencies in a time division multiplexing fashion. In some cases there is no penalty in dynamic range; in others, the penalty is more strongly related to the reduction in the number of photodetectors. Similar techniques are applied to a cross-spectrum analyzer that uses temporal heterodyning to derive angle of arrival information from wideband signals.
© 1988 Optical Society of America
A. VanderLugt, "Use of decimated photodetector arrays in spectrum analysis," Appl. Opt. 27, 2061-2070 (1988)