PHOTON ENERGY DETECTOR GENERATING SIGNAL IN WHICH DURATIONS OF FIRST AND SECOND HALF CYCLES ARE RESPONSIVE TO PHOTON ENERGY AND DIODE CONTINUITY RESPECTIVELY

摘要

A relaxation oscillator produces a cyclical output signal having alternate first and second half cycles. The oscillator includes a timing circuit having a resistance-capacitance network. The resistance includes a PIN photo diode which exhibits a reverse leakage current responsive to the photon energy incident upon the diode. The photo diode defines the duration of the first half cycles as a function of the reverse leakage current of the diode and defines the duration of the second half cycles as a function of the forward drive current of the diode. The first and second half cycles of the output signal are averaged to provide an output level having a magnitude which is responsive to the photon energy incident upon the photo diode and is responsive to the continuity of the photo diode.