Abstract: An articulated viewing apparatus (10) has a pair of elevational actuators (56, 78), one of which is a coarse-position actuator (56) and the other of which is a fine-position actuator (78), and each of which pivots a mirror head (28) about respective parallel elevational axes (54, 66'). Pivotal movements of the mirror head (28) direct the line of sight of a viewer looking outwardly through a window (22). The window (22) may be formed in the wall of a vehicle or may be at the upper end of a periscope tube, for example, and includes a transparent material (24). This window (22) may admit light to an optical sensor or to the user's eye directly. The coarse-position elevational actuator (56) is positioned so that its axis (54) is located as close as possible to an edge of the mirror head (28) and close to the inner surface of the window glazing (24) so that the size of the window (22) is minimized with respect to the size of the optical aperture and field of view provided to the user of the apparatus (10).

Abstract: A DC to AC inverter that includes a first capacitor (11) and a first inductor (13) connected in series between a positive voltage supply node and a central node; a first active switch switching (15) connected across the first capacitor and driven with a first periodic drive signal of a predetermined frequency; a second capacitor (21) and a second inductor (23) connected in series between a negative voltage supply node and the central node; a second active switch (25) connected across the second capacitor and being driven with a second periodic signal of said predetermined frequency and being out of phase by 180 degrees relative to the first periodic drive signal; a bandpass filter (31, 33) connected between the central node and an output node; and a load (47) connected between the output node and ground.