Patent GB-779883-A (GB)
Title: Improvements in or relating to high-speed electronic counters
Inventor: NUTTALL THOMAS CAYTON
IPC: H03K23/82
Filed: 1954-10-21
Abstract: 779,883. Electronic counters; patternmovement stepping registers. CINEMATELEVISION, Ltd. Nov. 18, 1955 [Oct. 21, 1954], No. 30336/54. Class 106(1). A counter or shifting register comprises a ring- connected plurality of stages each comprising a balanced artificial transmission line, a first pair of normally operative valves having- their control grids energized in antiphase by the transverse signal voltage at a first point on the transmission line, and a second pair of normally inoperative valves having their control grids energized in antiphase by the transverse signal voltage at a second point on the transmission line, applied signals for stepping along the pattern of transverse voltages rendering the first pair of valves inoperative and the second pair of valves operative for the.duration of each signal. In the described embodiment a ring of five stages may be operated as a shifting register or as a counter decade. Two stages of the ring are shown in Fig. 1. The effect of each input pulse is to momentarily raise the potential on terminals 5, 5<SP>1</SP>, &c., thus cutting off the conducting one of the cross-connected valves 1, 2, 1<SP>1</SP>, 21, &c., and to lower the potential on terminals 6, 6<SP>1</SP>, &c., so as to allow one of the normally non-conducting, cross-connected valves 3, 4, 31, 41, &c., to conduct. At the termination of an input pulse the circuit is left with one valve of each pair 1, 2, 1<SP>1</SP>, 2<SP>1</SP>, &c., conducting and all the other valves blocked. The manner in which the condition of each stage is transmitted to the next stage is illustrated by a transfer from stage I to stage II, Fig. 1. Initially valves 1 and 1<SP>1</SP> are assumed to be conducting and therefore anode current flowing through elements 10, 12, 14 and 26 from H.T. terminal 27 produces a cut-off potential at the grid of valve 2, and similarly in the case of valve 2<SP>1</SP>. Although both pairs of valves 3, 4 and 31, 41 are cut-off by the potential communicated to their cathodes from terminals 6 and 61, valves 4 and 41 are both subject, in addition, to lower control grid potentials by virtue of the anode currents mentioned above. Thus, when an input pulse is applied to all the stages simultaneously, cutting off all valves 1, 2, 1<SP>1</SP>, 21, &c., and preparing for one valve of each pair 3, 4, 3<SP>1</SP>, 4<SP>1</SP>, &c., to conduct, the valves 3 and 3<SP>1</SP> will be the first to respond. The changeover of conductance from valve 1<SP>1</SP> to valve 3 will leave undisturbed the current flow through elements 10<SP>1</SP>, 121, 141 and 261, so that, upon the termination of the input pulse, valve 1<SP>1</SP> of stage II will respond and recommence conduction to represent the condition transferred from stage I, valve 3 once again becoming non-conductive. If, initially, valves 2 and 1<SP>1</SP> were operative, valve 4 will become conductive when an input pulse is applied, and this will lead to the valve 2<SP>1</SP> of stage II becoming conductive at the termination of the input pulse. A cross-over connection 31 may be made between two of the stages of the ring to provide for a counting cycle of ten pulses as indicated in Fig. 3 (not shown). Other arrangements are described. The shunt capacitance at those points in the delay lines to which a valve electrode is connected is comprised mainly by the self- and inter-electrode-capacitance of the valve. Specifications 779,881 and 779,882 are referred to.