Patent ID: 8081674

Claim:
A method for determining whether distortion or noise is the dominant impairment on an impaired communication channel, comprising the steps of: establishing a sample size (N), a test duration, and a query rate for developing a complementary cumulative density function (CCDF) statistical measure of test signal measurements on a test channel; selecting and remotely instructing a network element to transmit test signals on the test channel; monitoring test signals at a headend of the test channel and recording measurements of signal-to-noise ratio (SNR) and Receive Power Level (Pr) on the test channel for samples 1 to N at the established query rate for the established duration; developing a CCDF for Receive Noise Power Level (Nr) from samples 1 to N, where Nr=Pr−SNR for each sample; obtaining a theoretically expected CCDF of Receive Noise Power Level for an Additive White Gaussian Noise (AWGN) dominated impairment on the test channel; and comparing the CCDF for Receive Noise Power Level developed from samples 1 to N relative to the theoretically expected CCDF of Receive Noise Power Level for an AWGN-dominated impairment and concluding therefrom whether the dominant impairment is distortion or noise.