Patent ID: 8379702

Claim:
A transmission line pre-emphasis circuit, comprising: a primary signal path coupled to receive a digital data stream to be transmitted and provide a primary differential output current indicative of the digital data stream; a secondary signal path incorporating a network implementing a specific transient response, the secondary signal paths receiving the digital data stream and generating a secondary differential output current representing an overshoot signal indicative of the transient response of the respective network and synchronized with transitions of the digital data stream, the secondary differential output current being summed with the primary differential output current of the primary signal path; and an output loading stage coupled to receive the summed differential output current to generate a pre-emphasized digital output signal to be transmitted onto a transmission line indicative of the overshoot signal added to the digital data stream, wherein the secondary signal path comprises: a scaling sage having a pair of differential input terminals receiving the digital data stream and a pair of differential output terminals generating a scaling stage differential output signal, the scaling stage having variable scaling control being set by a respective DC programming signal; and a pulse shaping stage having a pair of differential input terminals receiving the scaling stage differential output signal and a pair of differential output terminals generating the secondary differential output current, the pulse shaping stage incorporating the network implementing the transient response being an overshoot pulse, wherein the overshoot pulses generated at the pulse shaping stage are summed with the primary differential output current to generate the pre-emphasized digital output signal having the overshoot pulses synchronized with transitions of the digital data stream, the overshoot pulses having a variable pulse width modified by the DC programming signal.