Application of pulse-width modulated pre-emphasis in closely-spaced transmission lines with additional discontinuities

Transmitter pre-emphasis techniques to overcome high-slope losses of printed circuit board (PCB) with closely-spaced copper interconnect are presented. The pre-emphasis technique based on pulse-width modulation (PWM) using a timing resolution instead of an amplitude resolution to adjust the filter transfer function is presented. In addition only one coefficient can be used to set the equalizer transfer function depending on channel properties. The standard approaches to transmitter pre-emphasis, receiver equalization and PWM pre-emphasis are compared in advanced PCB backplane models.