Abstract: A pseudo random noise code generator in which a modular type shift register includes a multiplexer selecting the input for every stage thereof and a flipflop, whose input is the output of the multiplexer, the flipflop serving as the highest stage of the modular type shift register and feeding back the output thereof to each of the stages, and it is possible to control the number of stages of said shift register in operation by address-controlling the modular type shift register.

Abstract: A control circuit such as a microcomputer sets only the starting address of the memory in which initial information for generating a maximum length recurring sequence is stored and the number of chips of the maximum length recurring sequence and the initial information for generating a maximum length recurring sequence is set from the memory in the maximum length recurring sequence generator by a hardware. The hardware for accessing the memory is constructed by a counter working with a high speed clock. The number of chips of the maximum length recurring sequence set by the external control circuit is counted by a counter working with a high speed clock.

Abstract: A maximum length shift register sequence generator capable of changing the format and phase of an M code known as maximum length shift register sequences in the transmitter and receiver. The register is most suitable for use in spread spectrum communication systems adapted to effect transmission by correlation between an M code from the transmitter and such an M code generated in the receiver. The generator includes a latch for storing the format and initial phase of an M code to be generated subsequently, and a microprocessor for setting in the latch necessary data required for changing the M code. A change of the M code is effected by a strobe signal lasting for a time equal to the lasting time of one clock pulse.