Error Margin Estimating in Repeaters

In this paper a new method of estimating error margin in
T
carrier repeaters is proposed. This estimate is based on two sets of data: (a) measurements from a commonly used test wherein bipolar violations are inserted into the line at an audio rate, and (b) the crosstalk environment in which the repeater is operating. An audio component due to violations in the bipolar signal causes a shift in the eye pattern resulting in a change of repeater error rate. This in turn changes the regenerated audio signal power by an amount depending on the initial undisturbed error rate of the repeater. This then gives a basis for extrapolating the operating error rate of a repeater from a test measurement. This error rate combined with a knowledge of the cable crosstalk parameters and number of operating systems during the test, is then used to estimate the error margin or eye opening of the repeater, assuming a Gaussian distribution for the interference. A method of ranking repeaters in a repeatered line to indicate their relative margin is proposed wherein the effect of errors on the audio signal to an intermediate test repeater is taken into account. Results presented are quite general and valid at any line rate and repeater spacing, and hence applicable for different
T
-carriers such as
T1, T1C, T2
, etc.