FIR Filters

Finite Impulse Response Filters

Above is shown the Tap Delay Line version of an FIR filter. It can actually be created in an analog circuit using transmission lines for the T Delay, resistors, an opamp, and an inverting summer to sum them all together. In the digital sense whats really happening here is that the output of the FIR filter (y(l)) is the convolution of h(l) with x(l) as shown below.

It can simply be viewed as a multiply and accumulate becuase we are simply taking a predifined impulse function h(l) which will filter the signal how you want and multiplying it by x(l).