Patent GB-872466-A (GB)
Title: Improvements in or relating to electric pulse distributors
Inventor: BREWSTER ARTHUR EDWARD
IPC: G11C7/02
Filed: 1959-11-09
Abstract: 872,466. Circuits employing bi-stable magnetic elements. STANDARD TELEPHONES & CABLES Ltd. Nov. 9, 1959, No. 37890/59. Class 40 (9). [Also in Group XL (c)] In an electric pulse distributer, a sequence of pulses 12 to 15, Fig. 3, is generated on reversal of a voltage E of constant magnitude applied to the series-connected trigger windings 5, Fig. 1, of a number of differently biased but otherwise identical cores 1 to 4. The pulses are generated in output windings 7 and are fed to terminals 12 to 15. Cores are represented by thick black lines. Thin lines sloping to the left and to the right respectively indicate windings wound in opposite senses. Bias windings 6 on cores 1 to 4 have m to 4m turns respectively. Relay 8 connects positive and negative batteries 9, 10 alternately to trigger windings 5. The output pulses are spaced further apart if they are taken from alternate cores as in Fig. 4. The spacer cores 43, 44, 45 have no output windings. Outputs are taken from cores 39, 40, 41, 42. The bias windings are wound in one sense on cores 39, 43 and 40 and in reverse on cores 41, 45 and 42. The bias windings on cores 40 and 41, 43 and 45, 39 and 42 have m, 2m, 3m turns respectively. A generator 47 periodically reverses the voltage E on the trigger windings 5. Each core 39 to 42 has two output windings of opposite sense. In one cycle of two voltage reversals, eight pulses are generated. The pulses appear on terminals 31 to 38. Each core is switched twice in a cycle and rectifiers 46A, 46B, &c., steer the pulses to one terminal only for each switching operation. The increase of current in the trigger windings 5 when all four cores are saturated after each voltage reversal is used to control the voltage generator. The two successive pulses generated by each of cores 42 and 39 do not overlap as the rate of change of flow changes sign when the control voltage is reversed and the output voltage must go through zero. Voltage generator.-Two PNP transistors 50A, 50B operate as a multivibrator which produces a periodic reversal of voltage on lead 58 at a frequency determined by the condensers 57A, 57B and the associated resistors when the switches 59A, 59B are set as shown. NPN transistors may be used. If the switches are connected to terminals 61A, 61B the transistors are linked to additional cores 62A, 62B, Fig. 6, in the distributer and are triggered whenever these cores are triggered at the end of each reversal. The flux change in the cores 62A, 62B is limited to about 10% of the flux change in an output core. The reversing windings may be wound on cores 39, 42. Synchronous working.-The distributer shown in Fig. 4 may be synchronized by a crystalcontrolled oscillator 68, Fig. 7, running at approximately the same frequency as the voltage generator. The oscillator is coupled through a transformer 67 to windings 66 which are wound in one sense on cores 39, 41 and reverse on cores 40, 42. The pulses 70 to 73, Fig. 8, introduced into the transformer circuit by the cores 39 to 42 form an approximately sinusoidal wave. The oscillator 68 is tightly coupled to the cores by windings 66 of low resistance. A resistor 69 loosens the coupling of the trigger windings 5 to the cores. The oscillator pulls the generator into step.