Abstract: In a digital angle coder, a revolving disc bears a first series of marks ularly spaced around its axis, capable of being read by two diametrically-opposed fixed heads, and a second series of marks equal in number to the first, regularly spaced around the axis and capable of being read by two diametrically opposed movable heads. Each of the heads includes, for example, a grid reproducing a portion of the series of marks, a photo-emission element and a photo-receiving element. A first auxiliary mark may be read by a fixed auxiliary head and a second auxiliary mark may be read by a movable auxiliary head.

Abstract: An electronic device for amplifying, with automatic gain control by discr values, analogue signal samples and thereafter preferably effecting analogue-to-digital conversion of the samples, consists of an amplifier circuit, a comparator circuit, and a delay store circuit. The amplifier has a basic gain during a gain control or gain ranging operation, and supplies an output sample amplified with sufficient gain to bring it into the region of a predetermined voltage. The comparator circuit compares the output of the amplifier circuit with a reference and supplies an output in accordance with the result of the comparison. For analogue-to-digital conversion the amplifier circuit supplies for an input signal U an output signal 2U - VQ, where VQ is the quantification voltage, or, in other embodiments a signal 2U.