Method and system for detecting non-linear devices

摘要

To assist with the detection of unfiltered device(s), a system observes how the received noise changes between two links as the transmit signal is changed. Harmful unfiltered nonlinear devices will generate significant noise that depends on the transmitted signals; therefore, this additional noise can be quantified to some extent by comparing the observed noise for two different transmit signals. The total noise can be determined from the SNR if the received signal is known. The received signal may be read directly in some non-standard systems, or it may be determined from the known transmit signal and channel attenuation, which is sometimes the case in standard-compliant links, but often with a relatively large error. To circumvent this problem, certain embodiments of this invention only consider the change in noise between two links with the same channel attenuation. This differential comparison makes it unnecessary to accurately know the channel attenuation.

主权项

1. An unfiltered device detection method, implemented by an unfiltered device detection system, comprising:
initiating a first link with a first power spectral density (PSD) profile; obtaining and storing, in a memory, first signal to noise ratio (SNR) and transmit power levels based on the first link; initiating a second link with a second PSD profile different than the first PSD profile; obtaining and storing, in a memory, second SNR and transmit power levels based on the second link; and identifying, by processing circuitry, at least one unfiltered device by comparing the first SNR and transmit power levels to the second SNR and transmit power levels, wherein the comparison of the first SNR and transmit power levels to the second SNR and transmit power levels is made to determine a ratio of a noise on the first link, N1, to a noise on the second link, N2, as follows:
N1 /N2=(S1*SNR2)/(S2*SNR1), where S1 and S2 are the respective transmit power levels on the first link and second link, and SNR1 and SNR2 are the respective SNR values on the first link and second link, and the at least one unfiltered device is determined to be present when the value of N1/N2 is above a predetermined threshold value.