wiki:DSP/Interpolation

Version 1 (modified by dlambros, 9 years ago) ( diff )

Interpolation Tutorials

Introduction

Interpolation, also known as upsampling in the case of Digital Signal Processing, is a process that provides an approximation of the signal that would have been obtained if it had been sampled at a higher sample rate.

Before continuing with this tutorial for further reading for understanding Interpolation read the following resources:

Materials Required

Installing GNURadio

If running on a Ubuntu or Debian distribution of Linux use the following command for installation:

sudo apt-get install gnuradio

For other OS's follow the instructions from this guide.

Interpolation of a Sinusoidal Wave with GNURadio

In GNURadio on your computer implement the following flow chart to obtain the following FFT and Scope Plots:

Next add a Interpolation FIR Filter with an Interpolation of 3 as seen below:

Verify that the Scope and FFT plots are:

The waveforms can be seen with 3 zeros inserted from the Interpolation FIR Filter between every sampled point. Next apply a Low Pass Filter as seen below to smooth out the waveform.

Verify that the smoothed out signal plots resemble:

Interpolation of a .WAV File with GNURadio

For the following download the .WAV File and listen to the audio file. Then set up the following flowgraph in GNURadio: Go back to the original .WAV File and listen to the audio. Then listen to the output file and notice the difference and effects of upsampling an audio sample.

Interpolation of a Sinusoidal Wave with Octave

Attachments (18)

Download all attachments as: .zip

Note: See TracWiki for help on using the wiki.