Changes between Version 1 and Version 2 of DSP/Interpolation


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Timestamp:
Jun 2, 2015, 12:38:03 AM (9 years ago)
Author:
dlambros
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  • DSP/Interpolation

    v1 v2  
    99* [http://dspguru.com/dsp/faqs/multirate/interpolation DSPGuru - Interpolation]
    1010* [http://en.wikipedia.org/wiki/Upsampling Wiki - Upsampling]
     11
    1112== Materials Required ==
    1213* [http://www.orbit-lab.org/userManagement/register Orbit Account]
    … …  
    1415* Reservation on Orbit Lab
    1516* WAV File 
     17
    1618== Installing GNURadio ==
    1719If running on a Ubuntu or Debian distribution of Linux use the following command for installation:
    … …  
    2123
    2224For other OS's follow the instructions from this [http://gnuradio.org/redmine/projects/gnuradio/wiki/InstallingGR guide].
     25
    2326== Interpolation of a Sinusoidal Wave with GNURadio ==
    2427In GNURadio on your computer implement the following flow chart to obtain the following FFT and Scope Plots:
    25 [[Image(img1.png)]]
    26 [[Image(img2.png)]][[Image(img3.png)]]
     28
     29[[Image(img1.png,650px)]]
     30
     31[[Image(img2.png, 500px)]][[Image(img3.png, 500px)]]
    2732
    2833Next add a Interpolation FIR Filter with an Interpolation of 3 as seen below:
    29 [[Image(img4.png)]] [[BR]]
     34
     35[[Image(img4.png,650px)]] [[BR]]
    3036
    3137Verify that the Scope and FFT plots are:
    32 [[Image(img5.png)]][[Image(img6.png)]]
     38
     39[[Image(img5.png, 500px)]][[Image(img6.png, 500px)]]
    3340
    3441The 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.
    35 [[Image(img7.png)]]
     42
     43[[Image(img7.png, 650px)]]
    3644
    3745Verify that the smoothed out signal plots resemble:
    38 [[Image(img8.png)]] [[Image(img9.png)]]
     46
     47[[Image(img8.png, 500px)]][[Image(img9.png, 500px)]]
    3948== Interpolation of a .WAV File with GNURadio ==
    4049For the following download the .WAV File and listen to the audio file. Then set up the following flowgraph in GNURadio:
    41 [[Image(img10.png)]]
     50
     51[[Image(img10.png, 650px)]]
     52
    4253Go 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.
    4354== Interpolation of a Sinusoidal Wave with Octave ==