US Patent 7138835 Method and apparatus for an equalizing buffer

A programmable, equalizing buffer is provided having feedback transistors used to vary the transfer function of the equalizing buffer, such that a low pass response of a transmission channel is substantially equalized. A zero in the buffer's transfer function is established by a conductive state of transistors caused by signal feedback. Multiple transistors establish increased flexibility for establishing the location of the zero, while a cascade of buffer stages provides a second order transfer function effective to cancel second order channel effects.