Abstract: The detector circuit (11) of a radiation-sensitive sensor (10) with capacitive high pass coupling (14) between a pre-amplifier (13) and a signal amplifier (15) is blocked for a prolonged period of time (T2) even after termination of an overexcitation effect, because of the high filter time constant of the series capacitor (25), because the capacitor (25) only slowly experiences charge reversal and therefore the signal amplifier (15) following it initially still remains overdriven until the capacitor (25) has reversed charge again to a dc voltage level in the actuation range (39) of the signal amplifier (15). That dead time period (T2) is however curtailed to a short fraction (T1) if upon termination of overexcitation at the input side the capacitor (25) at the output side, that is to say upstream of the signal amplifier (15), is forcibly returned to the—virtual—ground potential at the amplifier input, for potential reduction purposes, by way of a low-resistance switching section (31).

Abstract: Described is a testing system which has a target point light source (12), a tracking light source (18) and therebetween a projection wall (24). Associated with the target point light source (12) is a two-axis deflection device (28) which is connected together with a target point computer (14). Associated with the tracking light source (18) is a two-axis scanner device (30) which is connected together with a tracking computer (20). Provided between the tracking light source (18) and the two-axis scanner device (30) is a beam splitter (32) with which a sensor device (42) is associated.

Abstract: A target acquisition apparatus (10) having a laser beam source (12), wherein associated with the laser beam source (12) is an opto-mechanical tracking device (14) having a receiver (38) for reception of the laser beam which is reflected by a target (28). For evaluation of the signals of the receiver (38) there is provided an electronic evaluation device (18) which is connected together with the opto-mechanical tracking device (14). The receiver (38) has a photovoltaic four-quadrant detector (36) by which two orthogonal spatial direction co-ordinates (X, Y) are established. In order to compensate for dissimilar performance on the part of the quadrant detectors (E1, E2, E3, E4) of the four-quadrant detector (36) as is not to be ruled out for example due to temperature-induced or ageing-induced drift, the electronic evaluation device (18) is provided with switches (S1, S2, S3, S4) for signal inversion purposes.