Multirate Filtering: Introduction

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Multirate Filtering: Introduction 2.21 2001/05/31 2009/06/03 15:24:34.539 GMT-5 Douglas L. Jones Douglas L. Jones dl-jones@uiuc.edu Swaroop Appadwedula Swaroop Appadwedula appadwed@uiuc.edu Matthew J. Berry Matthew Berry mjberry@uiuc.edu Mark A. Haun Mark Haun markhaun@uiuc.edu Jake Janevitz Jake Janovetz jake@janovetz.com Michael L. Kramer Michael Kramer kramer@ifp.uiuc.edu Dima Moussa Dima Moussa dmoussa@uiuc.edu Daniel Grobe Sachs Daniel Sachs sachs@uiuc.edu Brian Wade Brian Wade bwade@uiuc.edu Douglas L. Jones Douglas L. Jones dl-jones@uiuc.edu Swaroop Appadwedula Swaroop Appadwedula appadwed@uiuc.edu Matthew J. Berry Matthew Berry mjberry@uiuc.edu Daniel Grobe Sachs Daniel Sachs sachs@uiuc.edu Mark D. Butala Mark Butala butala@uiuc.edu Ricardo Anthony Radaelli-Sanchez Ricardo Radaelli-Sanchez ricky@alumni.rice.edu Robert L. Morrison Robert Morrison rlmorris@uiuc.edu Douglas L. Jones Douglas L. Jones dl-jones@uiuc.edu Swaroop Appadwedula Swaroop Appadwedula appadwed@uiuc.edu Matthew J. Berry Matthew Berry mjberry@uiuc.edu Mark A. Haun Mark Haun markhaun@uiuc.edu Jake Janevitz Jake Janovetz jake@janovetz.com Michael L. Kramer Michael Kramer kramer@ifp.uiuc.edu Dima Moussa Dima Moussa dmoussa@uiuc.edu Daniel Grobe Sachs Daniel Sachs sachs@uiuc.edu Brian Wade Brian Wade bwade@uiuc.edu decimation downsample DSP interpolation multirate sampling multirate system sample-rate compressor sample-rate expander upsample Science and Technology A sample-rate compressor removes (D-1) of every D input samples. A sample-rate expander inserts (U-1) zeros after every input sample. en

Introduction In the exercises that follow, you will explore some of the effects of multirate processing using the system in . The sample-rate compressor ( ↓ D ) in the block-diagram removes D 1 of every D input samples, while the sample-rate expander ( ↑ 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 F s D .

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