Abstract— Very-high-speed digital subscriber loop modems

operate in frequency bands, which coincide with many significant

radio-frequency interference sources, particularly commercial

AM radio. In these bands, the balance of most twisted-pair cables

is low enough to allow substantial interference to transfer to

differential mode, disrupting the transmitted information signal.

A novel wideband common-mode noise cancellation technique is

presented. Simulation results show that the common-mode noise

cancellation technique could provide 20- to 30-dB improvement

in those radio frequency bands. Construction and testing of a

hardware prototype are also presented. With finite-precision

effects, measured test results show that common-mode noise

cancellation in the order of 15–20 dB is achievable.