GB866237A - Improvements in or relating to integrating apparatus - Google Patents

Abstract

866,237. Photo-electric evaluating apparatus. PHILIPS ELECTRICAL INDUSTRIES Ltd. Jan. 31, 1957 [Feb. 3, 1956], No. 3430/57. Class 40(3) [Also in Group XXXVI] In apparatus for integrating a record function Y of an independent variable (time), periodic electric pulses are counted during a variable part of a counting period which corresponds to one revolution of a surface which is scanned, the variable part being determined by scanning means which senses the presence or absence of a local quality upon the surface along a scanning path determined by the value of a first function X of the independent variable. A light source 12 is focused on to a cylindrical surface 20 from which it is reflected and focused on to a photoelectric cell 15 which actuates a switch 17 to permit pulses from a generator 18 to be fed to a counter 19. The cylinder is rotated, at constant speed, by electric motor 21; and part of its surface is blackened, the boundary corresponding to a function Y=f(X) where X, Y are the first and second functions of the independent variable (time), to prevent reflection of the light beam on to the cell 15. The scanning means, comprising the light source 12, lenses 13, 14, and cell 15, is attached to a carriage which is moved parallel to the cylinder axis by a screw spindle 10 rotated by servomotor 9; this motor being controlled by the output voltage across the tappings on potentiometers 2, 3 of a bridge circuit; the carriage 11 is thus caused to move along the spindle 10, carrying one tapping along the potentiometer 3 until the bridge is balanced. Thus, as the tapping on potentiometer 2 is moved in accordance with the variable X, the carriage 11 moves similarly to select the corresponding scanning path on the rotating cylinder 20; the pulse counter 19 providing a value of the integral of Y with respect to the independent variable, time. In a second embodiment, Fig. 3 (not shown), a glow-lamp serves both as light source and pulse generator. Alternatively, a steady light source may be used and the reflecting part of the rotating cylinder shaded in parallel bands, Fig. 5 (not shown), to periodically interrupt reflection and thus provide pulses of reflected light. In a third embodiment, Fig. 8, the surface of revolution is a transparent disc 28 part of which is covered with an opaque sheet 27 representative of the function Y=f(X), the disc being rotated by motor 21. A tubular light source 29 extends radially beneath the disc, and light transmitted through the disc is focused on to the cell 15 by the lens 14. The cell operates a relay 17 which on closing causes the pulse generator 18 to operate, the pulses being counted as before. In a fourth embodiment, Fig. 6 (not shown), the opaque sheet is of insulating material, and the rotary disc is of conductive material. The photo-electric scanning mechanism is replaced by an electric contact which rides on the disc and thereby connects the pulse generator to the pulse counter unless the insulating sheet breaks the circuit.