Circuit for detecting word sequences in a modem

摘要

A device for identifying a determined repetitive sequence of predetermined signals arriving on a modem. The device includes a delay circuit so that all the words of a sequence are simultaneously present; a combination circuit for providing a combined word; a circuit for calculating the modulus of each combined word and for comparing this modulus with a threshold; a circuit for counting clock pulses corresponding to the rate at which words arrive; a circuit for inhibiting the counting circuit when the modulus of the combined word is lower than the threshold; and a circuit for providing an identification signal when a predetermined number of clock signals is counted.