The AT76C001 Programmable Finite Impulse Response (FIR) Filter implements a 4th order FIR cell built around 4 multiplier-accumulators. It contains a dual-port RAM and a RAM which are used to implement FIR filters of up to 256 taps. High order filters are achieved by multiplexing the 4th order cell and accumulating the intermediate results up to 40 bits, so that there is no loss of accuracy. The maximum frequency of the AT76C001 is 27 MHz. For 4-tap FIR filter, the incoming sample rate can be as high as 27 MHz. For higher order FIR filters, the sample rate can be as high as the circuit frequency divided by the 4th order cell multiplexing factor.