A fast parallel approach to the spectral analysis of a time-varying signal is presented. The technique, which uses a light emitting diode array and an integrating photodiode array, can offer the potential of a thousand or more spectral points and data rates beyond 10 MHz.
T. W. Cole, "Spectral analysis of a temporal signal with incoherent optics," Appl. Opt. 20, 145-148 (1981)