Abstract: An inter-symbol interference (ISI) loss filter device emulates frequency dependent losses to an electrical signal. The ISI loss filter device includes amplifier stages connected in series for cascading programmable poles or zeros in a signal path carrying the electrical signal. Each amplifier stage includes a high performance bypass path, a bandwidth limited path parallel to the high performance bypass path, a controllable signal router for routing a variable first and second portions of the electrical signal through the high performance bypass path and the bandwidth limited path, respectively, and a summing junction to combine outputs of the high performance bypass path and the bandwidth limited path for outputting a test signal with high and low frequency content. The high performance bypass path transmits an entire bandwidth of the first portion of the electrical signal, and the bandwidth limited path transmits a controllable limited bandwidth of the second portion of the electrical signal.