Question: An alternative method for designing an FIR filter that approximates the desired channel characteristics is based on the window method. To be specific, if the desired channel response is C(j) for If I ; W and C(j) = 0 for If I > W, the impulse response of the channel is
An equivalent digital filter may be implemented by sampling h(t) at t = nTs, where Ts is the sampling interval and n = 0, ±1, ±2, ... . Let us now design an FIR filter with W = 2000 Hz and F5 = l/T5 = 10 KHz.