https://github.com/sarfata/learning-dsp

Very naive C implementations of basic DSP functions
https://github.com/sarfata/learning-dsp

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Very naive C implementations of basic DSP functions

• Host: GitHub
• URL: https://github.com/sarfata/learning-dsp
• Owner: sarfata
• Created: 2013-03-27T19:24:54.000Z (almost 12 years ago)
• Default Branch: master
• Last Pushed: 2013-03-27T19:38:08.000Z (almost 12 years ago)
• Last Synced: 2024-11-08T15:00:30.727Z (about 2 months ago)
• Language: C
• Size: 512 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Learning DSP

Some very basic and crude implementation of DSP functions to test my understanding of signal processing.

Currently includes:

 * A Discrete Fourier Transform (DFT) function

 * Hanning Window when performing the DFT

 * Spectral magnitude calculation

And some useful tidbits to play with it:

 * Wave file loader

 * ASCII representation of a spectrum

# Usage

First parameter is a wave file, and the second parameter is the number of samples to perform a DFT on (the DFT will have that same length).

Wave file must be 16 bits, 1 channel only. I have tested mostly at 11025kHz although other bitrates should work too.

    $ ./fftfun samples/sine-3200.wav 512

    ./fftfun: put some DSP classes to work

    ChunkId   : RIFF

    Format    : WAVE

    Audio Format: 1

    Num Channels: 1

    Sample Rate: 11025

    Byte Rate: 22050

    Block Align: 2

    BitsPerSample: 16

    Data size: 44100

    NumSamples: 22050

    File duration: 2.000000

    Power @     0 Hz: -134.98 dB Magnitude: 0.00000

    Power @    22 Hz: -126.56 dB Magnitude: 0.00000

    ...

    Power @  2993 Hz:  -71.25 dB Magnitude: 0.00027 #############################

    Power @  3015 Hz:  -68.37 dB Magnitude: 0.00038 ################################

    Power @  3036 Hz:  -65.11 dB Magnitude: 0.00056 ###################################

    Power @  3058 Hz:  -61.40 dB Magnitude: 0.00085 #######################################

    Power @  3079 Hz:  -57.03 dB Magnitude: 0.00141 ###########################################

    Power @  3101 Hz:  -51.78 dB Magnitude: 0.00258 #################################################

    Power @  3122 Hz:  -45.13 dB Magnitude: 0.00554 #######################################################

    Power @  3144 Hz:  -35.98 dB Magnitude: 0.01588 #################################################################

    Power @  3165 Hz:  -20.51 dB Magnitude: 0.09428 ################################################################################

    Power @  3187 Hz:   -4.06 dB Magnitude: 0.62672 ################################################################################################

    Power @  3208 Hz:   -2.81 dB Magnitude: 0.72369 ##################################################################################################

    Power @  3230 Hz:  -14.71 dB Magnitude: 0.18384 ######################################################################################

    Power @  3252 Hz:  -33.45 dB Magnitude: 0.02126 ###################################################################

    Power @  3273 Hz:  -43.43 dB Magnitude: 0.00674 #########################################################

    Power @  3295 Hz:  -50.49 dB Magnitude: 0.00299 ##################################################

    Power @  3316 Hz:  -56.00 dB Magnitude: 0.00159 #############################################

    Power @  3338 Hz:  -60.51 dB Magnitude: 0.00094 ######...

# Author

Thomas Sarlandie - @sarfata - github.com/sarfata

# License

Public domain code. Do whatever you want with it. Comes with no warranty, etc.