Feedforward Comb Filter

$$\begin{eqnarray*} b_0 &=& \hbox{Feedforward coefficient}\\ b_M &=& \hbox{Delay output coefficient}\\ M &=& \hbox{Delay-line length in samples} \end{eqnarray*}$$

Difference Equation

$$y(n) = b_0 x(n) +b_M x(n-M)$$

Transfer Function

$$H(z) = b_0 + b_M z^{-M}$$

Frequency Response

$$H(e^{j\omega T}) = b_0 + b_M e^{-jM\omega T}$$