Abstract: Pulse detection apparatus for optical signal pulses including ultra-violet and infra-red frequencies. A photoconductive detector cell has four ohmic output electrode terminals disposed in a rhombic pattern and a centrally disposed input electrode terminal coupled to a source of direct current bias signal. Each pair of oppositely disposed output terminals defines an axis orthogonal to that defined by the other pair. Each pair of output terminals is coupled to a signal translation device such as a transformer with a center tapped primary or a differential amplifier. A pair of output signals are produced indicative of the degree of unbalance of the cell due to an optical signal impinged thereon.

Abstract: Optical detecting, tracking and indicating apparatus for producing a target angular position signal independent of target intensity. A photoconductive detector element has four outer electrodes disposed in a rhombic pattern and a centrally disposed inner electrode. A pair of quadrantly phased, alternating current primary bias signals are coupled to oppositely disposed electrode pairs. The central electrode is coupled through a load impedance and a source of secondary bias signal at a second frequency differing from the first bias signal frequency. A composite signal including both phase and frequency components of the primary bias signals appears in the output. The composite signal varies with target position and intensity. A secondary output signal at the second frequency varies only with intensity. A divider circuit divides the composite signal by the secondary signal to produce an output signal which varies only in accordance with the relative position of radiant energy impingent on the photoconductor.