Patent GB-826718-A (GB)
Title: Improvements in or relating to permutation code signal transmitters
IPC: H04L13/14
Filed: 1957-12-10
Abstract: 826,718. Printing-telegraph transmitters. WESTERN ELECTRIC CO. Inc. Dec. 10, 1957 [Dec. 31, 1956], No. 38375/57. Class 40 (3). A permutation code signal transmitter comprises a number of signal element storage devices interconnected in tandem with a signal relaying device associated with and controllable by the end one of the storage devices of which the remaining storage devices are selectively conditioned according to the marking and spacing elements of a permutation code signal combination, timing means including an oscillator and a multivibrator circuit which is adapted to generate a predetermined number of operative cycles per cycle of said oscillator, beginning under control of the oscillator at a predetermined point in a cycle thereof, for transferring said marking or spacing conditions along the tandem interconnections of the said storage devices and successively into said end storage device for correspondingly operating said relaying device. The character timing univibrator comprising the valve V2 is controlled by a phaseshift oscillator valve Vi operating at a frequency determined by one of four networks 100 connected in the anode-grid circuit of the lefthand (l.h.) section of the valve V1 by the contact bank B1 to four-level switch 101. The system is brought into operation by the movement of the switch 109, Fig. 2, to its terminal 2 so that the right-hand (r.h.) side of the valve V1 can pass amplified pulses to operate the character timer valve V2 acting as a univibrator whose period is controlled by capacitor 115 connected by contacts 1; 2 of the bank B2. Normally the l.h. triode of the valve V2 is conducting, and the r.h. triode non-conducting, but a negative pulse from the anode circuit of the oscillator valve V1 applied via capacitor 115 reverses the valve V2 which restores after a time corresponding to 6¢ element periods. A filter network 112, 118 delays conduction of the r.h. side of the valve VI following the operation of the switch 109. When the valve V2 changes over, a positive pulse from the l.h. triode of V2 is passed to the grid of the r.h. triode of the valve V5 which conducts for a period of 25 m.secs. and over conductor 158 operates a relay 159, Fig. 2, energizing a stepping magnet 301 which feeds the tape 302 so that its code perforations are sensed by the pins P1 ... P5. A positive pulse at the cathode circuit 119 of the valve V2 is also applied to the l.h. grid of the valve V4 which passes a negative pulse over conductor 123 to the l.h. grids of the valves V6 ... V11 which are all set to the spacing condition with the l.h. triodes non-conductive. Also, a negative pulse is applied with a delay effected by elements 126, 127, 128 over a conductor 129 leading to five gates each comprising a diode 204 and a network of resistors 205 ... 208, effective to reverse the register valves V6 ... V10 corresponding to those pins P1 ... P5 which are in engagement with their marking contacts M. When the l.h. triode of the valve V2 is made non-conducting, the grid of the righthand triode of the valve V3 changes towards positive so that its negative clamp is removed. Also the negative pulse over conductor 123 is passed to the grid of the l.h. triode of the element-timer valve V3 via contacts 1, 2 of the bank B3 and capacitor 140 so that the l.h. section is cut off and the r.h. section made conductive by a pulse passed over capacitor 141 and contacts 6, 7 of the bank B3. The negative pulse at the anode of the r.h. section is passed via capacitor 140 and contacts 1, 2 of bank B3 maintaining the grid of the l.h. section negative for a period dependent on the capacitor 140 and resistor 142. The capacitors 140, 141 have equal values and determine the element period which is correlated with the character time period as determined by the setting of the switch 101. Each time that the r.h. side of the valve V3 conducts a positive pulse is applied via capacitor 149 to the r.h. triode of the valve V4 which conducts and passes a negative pulse over conductor 153 to control the shifting of the pulses which have been established in response to the set-to-space and read-in impulse to the shiftregister. The back-bias on diodes such as 209, 210 connected between the double triodes V 10, V11 is determined by the conditions stored on these two valves, and if, for example, V11 is in the spacing condition and V10 is marking, the biases are such that the shift pulse is able to reverse the valve VI to the marking condition. If the valves V1 and V10 are in like conditions, the valve VI is unchanged, and in all cases a register valve assumes the condition of the next lower-numbered stage. Delay circuits such as 212, 213 and 214, 215 are provided to act as memory circuits for the transfer of the condition of a triode to the succeeding stage of the register. To provide the stop element, a condition simulating the marking condition of a triode of the register is set up on resistors 217, 218, 219 and the first shift pulse brings the triode V6 to the marking condition which is successively stepped so that on the sixth shift pulse the register triodes V6 ... V10 and the sixth stage triode V11 of the register are all in the marking condition. The output network between the valve V11 of the register and the l.h. triode of the valve V5 provides a marking output to the relay 227 when the valve V11 is in the marking condition or when the univibrator tube V2 is in the rest condition. In the arrangement shown the marking condition of the valve V11 or the rest condition of the valve V2 produces a negative voltage on the grid of the l.h. triode of the valve V5 so that relay 227 is operated to its contact M by a biasing winding. A spacing condition renders the l.h. section of the valve V5 conducting to operate relay 227 to its contact S. The output network may be modified so that the l.h. triode of the valve V5 is rendered conducting for the marking condition.