System for digital communication error measurements including shift registers with identical feedback connections

Claim 1

A SYSTEM FOR DIGITAL COMMUNICATION ERROR MEASUREMENT INVOLVING A TRANSMITTER TERMINAL, CHANNEL UNDER TEST, AND RECEIVER TERMINAL, A FIRST SHIFT REGISTER AT SAID TRANSMITTER TERMINAL HAVING A SIGNAL INPUT, SHIFT INPUT, AND STAGE OUTPUTS, A TIMING MEANS CONNECTED TO SAID SHIFT INPUT, AND FEEDBACK MEANS FROM CERTAIN STAGE OUTPUTS TO SAID SIGNAL INPUT, WHEREBY A QUASI-RANDOM BINARY FUNCTION OF A LENGTH DETERMINED BY THE NUMBER OF SHIFT REGISTER STAGES AND THE SELECTED FEEDBACK CONNECTIONS IS GENERATED AT THE SHIFT REGISTER INPUT, SAID FUNCTION ALSO BEING APPLIED THRU SAID COMMUNICATION CHANNEL TO SAID RECEIVER TERMINAL, A SECOND SHIFT REGISTER, TIMING SOURCE MEANS, AND IDENTICAL FEEDBACK MEANS AT SAID RECEIVER TERMINAL, WITH MEANS TO SYNCHRONIZE SAID RECEIVER TIMING MEANS TO THE FUNCTION RECEIVED THRU SAID CHANNEL, AND MEANS TO COMPARE THE FUNCTION GENERATED AT SAID RECEIVER WITH THE FUNCTION RECEIVED THRU SAID CHANNEL, WHEREIN THE INPUT CONNECTION TO SAID RECEIVER SHIFT REGISTER INCLUDES MEANS TO SWITCH FROM ONLY THE FUNCTION GENERATED AT SAID RECEIVER FEEDBACK MEANS TO INCLUDE THE FUNCTION GENERATED AT SAID TRANSMITTER TERMINAL AND APPLIED THRU SAID CHANNEL TO SAID RECEIVER TERMINAL AND THEN TO RESTORE CONNECTION TO ONLY SAID FEEDBACK MEANS, WHEREBY OPERATION OF SAID RECEIVER SHIFT REGISTER IS SYNCHRONIZED TO SAID TRANSMITTER SHIFT REGISTER, AND SYNCHRONIZED OPERATION OF SAID TRANSMITTER AND RECEIVER FEEDBACK REGISTERS IS MAINTAINED BY SAID TIMING SOURCES.

Claim 2

A SYSTEM FOR DIGITAL COMMUNICATION ERROR MEASUREMENT INVOLVING A TRANSMITTER TERMINAL, CHANNEL UNDER TEST, AND RECEIVER TERMINAL, A FIRST SHIFT REGISTER AT SAID TRANSMITTER TERMINAL HAVING A SIGNAL INPUT, SHIFT INPUT, AND STAGE OUTPUTS, A TIMING MEANS CONNECTED TO SAID SHIFT INPUT, AND FEEDBACK MEANS FROM CERTAIN STAGE OUTPUTS TO SAID SIGNAL INPUT, WHEREBY A QUASI-RANDOM BINARY FUNCTION OF A LENGTH DETERMINED BY THE NUMBER OF SHIFT REGISTER STAGES AND THE SELECTED FEEDBACK CONNECTIONS IS GENERATED AT THE SHIFT REGISTER INPUT, SAID FUNCTION ALSO BEING APPLIED THRU SAID COMMUNICATION CHANNEL TO SAID RECEIVER TERMINAL, A SECOND SHIFT REGISTER, TIMING SOURCE MEANS, AND IDENTICAL FEEDBACK MEANS AT SAID RECEIVER TERMINAL, WITH MEANS TO SYNCHRONIZE SAID RECEIVER TIMING MEANS TO THE FUNCTION RECEIVED THRU SAID CHANNEL, AND MEANS TO COMPARE THE FUNCTION GENERATED AT SAID RECEIVER WITH THE FUNCTION RECEIVED THRU SAID CHANNEL, WHEREIN THE INPUT CONNECTION TO SAID RECEIVER SHIFT REGISTER INCLUDES MEANS TO SWITCH FROM ONLY THE FUNCTION GENERATED AT SAID RECEIVER FEEDBACK MEANS TO INCLUDE THE FUNCTION GENERATED AT SAID TRANSMITTER TERMINAL AND APPLIED THRU SAID CHANNEL TO SAID RECEIVER TERMINAL AND THEN TO RESTORE CONNECTION TO ONLY SAID FEEDBACK MEANS, WHEREBY OPERATION OF SAID RECEIVER SHIFT REGISTER IS SYNCHRONIZED TO SAID TRANSMITTER SHIFT REGISTER, AND SYNCHRONIZED OPERATION OF SAID TRANSMITTER AND RECEIVER FEEDBACK REGISTERS IS MAINTAINED BY SAID TIMING SOURCES.