A
transmission line equalizer, communication
system, and method are provided for adaptively compensating for changes in transmission
path length and transmission path medium. Within the
equalizer is a filter that exhibits a high pass characteristic and, more specifically, has an inverse
frequency response to that of the transmission path. The
inverse filter can include a pair of
amplifier stages coupled in parallel, with a mixer chosen to adaptively select portions of
one stage over than of the other. The
dual stage inverse filter can, therefore, adapt to greater transmission path lengths and / or attenuation. A feedback architecture is used to set the
inverse filter response by measuring the amplitude of a communication
signal output from the inverse filter during periods of
low frequency. A peak
detector will capture a peak-to-peak
voltage value during those periods, and adjust the output of the slicer to match a launch amplitude of the communication
signal. The peak
detector within the feedback architecture helps ensure the predicted amplitude matches the launch amplitude to minimize over-compensation or under-compensation even though a different
integrator might register no difference in integrated
voltage or energy at the output of the inverse filter compared to the output of the slicer.