Patent GB-814138-A (GB)
Title: Improvements in or relating to electric signal generators
Inventor: HURR ERNEST ROY
IPC: H03K5/00
Filed: 1956-03-14
Abstract: 814,138. Pulse generating circuits. RANK CINTEL Ltd. March 13, 1957 [March 14, 1956], No. 7967/56. Class 40 (6). [Also in Group XIX] A pulse signal generator for producing pulses in any of a sequence of given time positions comprises a series of sequentially connected pulse counters each comprising a number of stages from each of which output signals are delivered in succession and a number of coincidence circuits supplied with the signals so as to select predetermined ones of them to develop pulse signals when energized simultaneously from a number of the outputs. Fig. 1 shows a pulse generator in which an oscillator 1 generates a signal having a predetermined period which is passed into a shaping circuit 2 to produce a pulse train which is applied to a repetitive counter 3 which assumes sequentially ten stable positions, outputs from each of the ten stages of the counter being available for selection by switch 4. The output of the last stage passes via delay circuit 5 to a further ten stable state counter 6, the output of each stage being available at switch 7. The final output of counter 6 is fed to coincidence circuit 12 as is also the final output from counter 3 so that when these two signals coincide an output signal is produced to operate counter 8, the output from the ten stages of which is available at selector switch 9. The selected outputs from switches 4, 7, 9 are fed to a coincidence circuit 10 which produces an output signal at 11 only when inputs are present at its three input terminals simultaneously. Thus if the timing signals generated by shaper 2 have a period of, for example 1 ms. then an output signal can be generated at any multiple of this interval up to 999 ms. after oscillator 1 operates. Fig. 2 shows a counter circuit suitable for any of the counters 3, 6, 8, Fig. 1, comprising counting tubes 21, 31 ... 41, 51 and cathode follower stages 23, 33 ... 43, 53. The circuit parameters are such that only one counting tube is operative at any one time and every positive input pulse supplied at terminal 72 causes the previously operated tube to be cut off and the next counting tube in the sequence to become operative. Terminals 61-70 are connected to the associated selector switch while the output from 73 is taken to the succeeding counter circuit. The counter may be re-set by operation of the push button 74. The negative output pulses are delivered at terminal 61- 70 having a duration equal to the interval between successive timing signals. For higher repetition rates counter circuits such as that described in Specification 779,882 may be used. Fig. 3 shows a coincidence or AND circuit to perform the functions of unit 10, Fig. 1. When any of the tubes 81, 82, 83 are operative the thyratron 85 does not strike but when all the tubes are cut off by negative pulses applied via selector switches from the associated counters thyratron 85 strikes to develop a negative output signal at terminal 11. Switch 87 operates to re-set the circuit to its initial condition, the input to tube 81 is fed via a differentiating circuit 88, 89. Fig. 5 shows a coincidence circuit to perform the functions of unit 12, Fig. 1, in which tubes 93, 94 are normally conducting. When both tubes are cut off by input pulses applied at A, B, tube 91 is rendered conducting the negative signal at its anode being applied to the counter 8, Fig. 1. In a modification shown in Fig. 4 the signals selected from timers 3, 6, 8 by switches 4, 7, 9 control a triple coincidence gate 12A which opens to allow a signal from shaping circuit 5 to pass to output terminal 11 only when gate-opening signals are received simultaneously from all three counters, thus the slight timing error which otherwise arises due to the finite operating time of counter 3 is avoided. Specification 572,884, [Group XL], also is referred to.