Equalization of Skin Effect Loss Dominated Channels using Pulse-Width Modulation (PWM) Pre-Emphasis

A digital transmitter pre-emphasis technique is presented that is based on pulse-width modulation, instead of finite impulse response (FIR) filtering. The technique fits well to future high-speed low-voltage CMOS processes. A 0.13μm CMOS transmitter achieves more than 5Gb/s (2-PAM) over 25m of standard RG-58U low-end coaxial copper cable. The test chip compensates for up to 33dB of channel loss at the fundamental signaling frequency (2.5GHz), which is the highest figure compared to literature