Patent GB-922590-A (GB)
Title: Improvements in or relating to electronic control apparatus
Inventor: NICHOLS JOHN WINFRITH DE LISLE
IPC: G01S1/68
Filed: 1958-07-22
Abstract: 922,590. Electric selective signalling systems. NATIONAL RESEARCH DEVELOPMENT CORPORATION. July 15, 1959 [July 22, 1958], No. 23540/58. Class 40 (1). A radio beacon control system causing the emission of a coded station identifying signal and a long uninterrupted signal used for bearing-obtaining purposes employs multicathode counting tubes as programme control devices. As shown, Fig. 1, a master oscillator O produces pulses at 8 kc./s. which are fed to a divider DV1 to produce basic pulses at the rate of four per second, a second divider DV2 producing pulses at one per minute. The output of the divider DV2 is fed to a counter CTR1 to produce six separate outputs connected to terminals BBHH on a connector panel CP, a selected terminal being connected to a terminal t to apply a control pulse of one minute duration to a gate G1 which is also supplied with basic pulses from the divider DV1. Five other similar beacon stations have their CTR1 counters initially synchronized by means not described, and operate sequentially by suitable selection of outputs from the counters CTR1. The terminal t is connected to a pulse generator PG1, which is operated when the terminal t is marked, the resulting output causing a ring counter RTR to step from its condition with stage 4 operative to the condition where stage 1 is operative. The stage 1 output of the ring counter RTR opens a gate G2 to allow basic pulses to pass to a ten-step counter CTR2. The ten outputs of the counter CTR2 are connected to three groups A-L, M-X, Y-f of 10, 10, 8 respectively terminals on the connector panel CP. The completion of each cycle of the counter CTR2 steps on a three-step counter CTR3, the outputs of which control three pairs of gates G5, G6; G7, G8; G9, G10, the other inputs to which are derived from terminals j, k; m, n; p, r, on the control panel CP which are cross-connected to selected ones of the terminals A-L &c. in accordance with the desired station identifying signal. The outputs of the gates G5, G7, G9 are commoned to a " mark rail " ML to turn on a trigger TRC and the outputs of the gates G6, G8, G10 are commoned to a " space rail " SL to turn off the trigger TRC, the trigger TRC controlling a relay C/2 which in turn controls the modulation of the radio transmitter (not shown) of the beacon. The characteristic station signal is a series of morse code dots and dashes. Thus the sequence of energization and de-energization of the relay C/2 is in accordance with the cross-connections on the control panel CP. The output of the counter CTR3 is to a counter CTR4 which has four outputs connected to terminals v-z, the connection of which to a terminal s which in turn is connected to a stage of the pulse generator PG1 determines the number of repetitions of the station identifying signal, the transmission of this signal ceasing when a pulse from the pulse generator PG1 causes the ring counter RTR to step on to stage 2, thereby closing the gate G2 and opening a gate G3. This causes application of the basic pulses to a further tenstep counter CTR5, the first step of which is connected to the mark rail ML to turn on the trigger TRC. Once each cycle of the counter CTR5, a twelve-step counter CTR6 is stepped, the eleventh output of which is connected to the space rail SL to turn the trigger SL off. Thus, since the basic pulses are at the rate of four per second, this arrangement causes an uninterrupted constant-amplitude signal of 25 seconds duration to be transmitted. The eleventh output of the counter CTR6 is fed also to a gate G4, whereby a slightly later output from the counter CTR5 provides an output to the stage 1 of the pulse generator PG1 and also resets the counters CTR5, CTR6. The ring counter RTR is thus stepped on to its stage 3 whereby a repetition of the transmission of the station identifying signal is initiated. When this transmission is completed, a further stepping pulse is applied to the ring counter RTR to step it to its stage 4 controlling the normal quiescent condition of the whole apparatus. Means are provided to reset the counter CTR2 at any chosen instant in the third of its three operation cycles if the whole period is not needed for code-signalling purposes. This is effected by connecting the terminal h on the panel CP to one of the terminal group Y-f. A connection of a further terminal AA to the appropriate terminal of the group v-z controls resetting of the counter CTR4 at the end of the operation. A detailed circuit for the apparatus is described (Figs. 2-7, not shown), the counters CTR1-CTR6 being multicathode gas discharge tubes, and the ring counter RTR and pulse generator PG1 each comprising four gasfilled trigger tubes. Means are provided whereby the apparatus may be operated continuously instead of for one minute in every six. The control arrangement described may be used in other applications, e.g. the control of machine tools.