GB1135718A - Code translator - Google Patents

Abstract

1,135,718. Codes. INTERNATIONAL STANDARD ELECTRIC CORP. 22 March, 1967 [29 March, 1966], No. 13459/67. Heading G4H. A coder for translating an n-digit code into another n-digit code includes three translating circuits which each translate an applied n-digit code into another n-digit code, the input signal being selectively fed to the circuits under the control of a programme stored in a memory. In the embodiment described (Fig. 6) the transformation which it is required to perform and which is the product of three transformations P, Q, R which are affected by circuits 20, 21, 22 is fed via a register 49 and AND gates 48 into the register 47 of a ferromagnetic matrix memory 50 causing read out in a subsequent time interval of one twenty-four bit row of the memory. Each two bits of the row represent one of the transformations P, Q, R and the contents of the register 43 are transferred to a shift register 40 which is shifted two bits at a time to successively enter the bits representing the transformation into a decoding circuit 39. The decoding circuit 39 enables one of the AND gates 32, 33, 34 to enable an n-digit number entered via OR gate 36 into a register 23 to be transformed in the associated circuit 20, 21, or 22 and then fed back into the register 23 to be operated on again in accordance with the next two bit digit entered into decoder 39. When two zero bits are stored in the left hand side of shift register 40, indicating that the programme is complete an output signal Fi from the decoder 39 enables an AND gate 37 so that the transformed n-digit code may be read out. If the programme comprises more than 12 successive transformations, it is stored in successive lines of the memory 50.