Error measurement for digital systems
AssigneeThe Marconi Company Limited
InventorStephen Ronald Robson
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Abstract
The quality of a transmission link is demonstrated by the number of samples of predetermined bit length (N) containing more than one bit in error. The distribution of errors, as it is called is determined by detecting the occurrence of an error, counting the number of bits from one error to the next error, evaluating for each sequence i of errors in which no three consecutive errors span more than (N + 1) bits the sum ##EQU1## WHERE A.sub.J = THE NUMBER OF BITS FROM THE JTH ERROR TO THE (J + 1)TH ERROR IN THE SEQUENCE, AND M = THE NUMBER OF ERRORS IN THE SEQUENCE, AND GENERATING THE CUMULATIVE SUM ##EQU2##
Claims8
A method of determining the number of samples in which the error rate in a bit stream exceeds 1 in N, where N is a predetermined sample size, by the steps of detecting the occurrence of an error in the bit stream, counting the number of bits from each error to the next, evaluating for each sequence (i) of errors in which no three consecutive errors span more than (N + 1) bits, the sum ##EQU7## where a.sub.j = the number of bits from the jth error to the (j + 1)th error in the sequence, and
- m = the number of errors in the sequence, and generating the cumulative sum ##EQU8##
An apparatus for determining the number of samples in which the error rate in a bit stream exceeds 1 in N, where N is a predetermined sample size, including error detection means for detecting the occurrence of an error in the bit stream, counting means for counting the number of bits from each error to the next, summing means for evaluating, for each sequence (i) of errors in which no three consecutive errors span more than (N + 1) bits, the sum ##EQU9## where a.sub.j = the number of bits from the jth error to the (j + 1)th error in the sequence, and
- m = the number of errors in the sequence, and means for generating the cumulative sum ##EQU10##
Dependencies are inferred from the claim text.