Lab 2: theory

Introduction

In the exercises that follow, you will explore some of the effects of multirate processing using the system in [link] . The sample-rate compressor ( $\downarrow (D)$ ) in the block-diagram removes $D-1$ of every $D$ input samples, while the sample-rate expander ( $\uparrow (U)$ ) inserts $U-1$ zeros after every input sample. With the compression and expansion factors set to the same value ( $D=U$ ), filters FIR 1 and FIR 3 operate at the sample rate $F_s$ , while filter FIR 2 operates at the lower rate of $\frac{F_s}{D}$ .

Later, you will implement the system and control the compression and expansion factors at runtime with an interfaceprovided for you. You will be able to disable any or all of the filters to investigate multirate effects. What purpose doFIR 1 and FIR 3 serve, and what would happen in their absence?