A method and apparatus are provided for channel equalization with a digital finite
impulse response (DFIR) filter using a pseudo random sequence. A readback signal
of a pseudo random bit sequence is obtained. Samples are obtained from the readback
signal of the pseudo random bit sequence. Tap gradients are calculated responsive
to the obtained samples. The tap weights of the digital finite impulse response
(FIR) filter are modified responsive to the calculated tap gradients. Dibit samples
and error samples are obtained from the readback signal of the pseudo random bit
sequence and applied to a tap gradients calculator. Tap gradients are calculated
by a bitwise multiplier and accumulation tap gradient calculation circuit. An attenuation
function attenuates the calculated tap gradients by a programmable attenuation value.