GB665714A - Improvements in or relating to electronic pulse generators - Google Patents

Abstract

665,714. Digital electric calculating-apparatus. FARRER, J. O (Remington Rand, Inc.). Aug. 9, 1949, No. 20750/49. Class 106 (i). Apparatus for generating electrical pulse trains, e.g. to be selectively used in electrical calculating apparatus, comprises a multivibrator 14, started by an electronic switching stage 13 under control of a switch 10, frequency divider stages coupled to the multivibrator for producing some of the pulse trains one of which consists of a single pulse, and coupling means between the frequency divider stages and the stage 13 for turning off the multivibrator when the single pulse ends. In the apparatus described, one or more of the pulse trains are selected by a keyboard 28, Fig. 1, to enter digits into an electronic accumulator including counter stages 35 as described in Specification 665,707. In operation, a digit key is depressed and then the start switch 10. A condenser 42, Fig. 2, is then discharged and a sharp positive pulse is applied to the grid of a pulse-generating triode 40, which sends a negative pulse 26, Fig. 5, a, over conductor 25 to change the condition of an unbalanced trigger stage 12 comprising a double triode 43. The output pulse 27, Fig. 5, b, is applied over conductor 39 to cathode follower stage 21 to supply a " 1 " pulse to the keyboard over line 63, and over conductor 45 to change the state of the trigger stage 13 and raise the potential on line 48 as shown at 30, Fig. 5, c, thus starting the multivibrator to produce pulses 31, Fig. 5, d. The multivibrator output is fed to cathode follower stage 20 to supply " 8 " pulses over line 94 to the keyboard (each pulse representing " 2 "), and also fed to frequency divider stages 15 and 16 to supply " 4 " and " 2 " pulses, Fig. 5, e and f, from cathode follower stages 22, 21, respectively. The output from stage 16 is also fed back over conductor 18 to stage 13 so that the trailing edge of pulse 33, Fig. 5, f, returns the stage to its normal condition (left-hand triode conducting), thus switching off the multivibrator. Pulses 32 and 33, Fig. 5, e and f, are sent also to a mixer stage 23 to produce output pulses, Fig. 5, g, which are fed to an inverter stage 24 which supplies " 6 " pulses, Fig. 5, h, to the keyboard.