Write channel equalization level control in magnetic recording device

A system for controlling write equalization levels in a magnetic recording device, comprising:

• a write equalization encoding apparatus having an input receiving a write data signal and a first output producing a write data signal and write equalization signal combination and having a second output producing a write equalization level signal;
• a digital-to-analog converter connected to receive both said write data signal and write equalization signal combination from said write equalization encoding device and said write equalization level signal from said write equalization encoding device, said converter being operable to convert digital write and equalization signals to analog signals, said digital-to-analog converter having an output signal of a first impedance for said write data signal, said digital-to-analog converter having an output signal of a second impedance for said write equalization level signal;
• a transmission line connected to receive an output of said digital-to-analog converter, said transmission line having a predetermined impedance at said input;
• and
• a write head connected at an output of said transmission line for receiving said analog write and equalization signals.