The Delay Line

The delay line models acoustic propagation delay.

Figure 13: The $M$-sample delay line.

The delay line introduces a time delay corresponding to $M$ samples between its input and output

$$y(n) = x(n-M), \quad n=0,1,2,\ldots$$

It is linear phase:

1. a phase delay of $M$ samples
2. delays all frequencies by this amount
3. IR is symmetric about $M^{th}$ sample