1. Introduction

     Sampling is essential to convert analog signal to digital signal. In this page, I would specifically
explain about downsampling. In digital signal processing, the decimator performs decimation, which is
downsampling a signal. In other words, when a digital signal is downsampled, the signal's sampling
rate would be reduced.
Intro1.jpg


2. Derivation


Sdf21le.jpg
Derivation2.jpg
Derivaa3.jpg 


3. Example


If) D = 2
Ex123.jpg
Ex4342e.jpg
Ex3g3le.jpg
Exam134gggge.jpg


4. Conclusion


      Downsampling reduces the magnitude by a factor of D, and increases the width of signals by D in the frequency domain. Moreover, it repeats it's signals every 2π and to prevent aliasing, decimator needs a lowpass filter before the downsampling.


Questions and comments

If you have any questions, comments, etc. please post them on this page.


Back to ECE438 slectures, Fall 2014

Alumni Liaison

has a message for current ECE438 students.

Sean Hu, ECE PhD 2009