A Signal generation and correction circuit with an LED diode (D1) and a photo-transistor (Q1) having corresponding inputs and outputs (d1e, d1a and q1e, q1a), as well as connecting lines (1, 2) leading to current terminals (A, B). The inputs and outputs (d1e, d1a) and/or (q1e, q1a) of the diode (D1) and the photo cell (Q1) arc connected so as to form a parallel circuit, wherein a resistor (R2) is arranged in the photo-transistor line (3) between the output (q1a) and the node (K) with the connecting line (2) and wherein a resistor (R1) is arranged in the line (2) between the node (K) and the current terminal (B). A transistor (Q2) is connected with its base (q2b) to the output (q1a) or the photo-transistor line (3), whereas the collector terminal (q2c) is connected via a resistor (R3) to the connecting line (1). The collector current has a value of 0 when a photo current flows in the photo transistor (Q1). A signal with a constant, adjustable magnitude is produced on the emitter side (q2e) of the transistor (Q2) in the absence of a photo current.
A gear-reduction device for measuring and transmitting the movements of a rotary object has a sequential arrangement of wheel/pinion pairs. Each wheel/pinion pair consists of a gear wheel and a pinion that are rigidly connected to a common gear axle. At least part of the gear wheels lie in different parallel planes that are inclined at an oblique angle in relation to the plane of rotation of the rotary object. The gear wheels are of equal diameter, and each of the pinions drives the next following gear wheel. The first wheel in the sequence of wheel/pinion pairs is driven by the rotary object, while the last of the pinions drives a swivel-mounted optical angle-measuring device.