notwa/dsp
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

update 40

Browse Source
This commit is contained in:
Connor Olding 2018-02-21 04:04:24 -08:00
parent c2a3c65687
commit d903249930
2 changed files with 36 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
README.md
View File

@ -4,31 +4,51 @@ it's a bunch of half-baked python code that's kinda handy.
don't expect commits, docs, or comments to be any verbose. don't expect commits, docs, or comments to be any verbose.
feel free to modify and adapt the [autoupdate](autoupdate)
shell script for your own repos like this!
## the stuff ## the stuff
* a basic BS.1770-3 normalization implementation * a basic BS.1770-3 normalization implementation
— [bs.py](/lib/bs.py) — [bs.py](/lib/bs.py)
* biquad butterworth/chebyshev filters [(via DSPFilters)][dspf] * biquad butterworth/chebyshev filters
[(via DSPFilters)][dspf]
— [nsf.py](/lib/nsf.py) — [nsf.py](/lib/nsf.py)
* bilinear transformation: s-plane to z-plane * modified bilinear transformation: s-plane to z-plane
— [planes.py](/lib/planes.py) — [planes.py](/lib/planes.py)
* various functions for biquad filters * various functions for biquad filters
— [bq.py](/lib/bq.py) [\_\_init\_\_.py](/lib/__init__.py) — [bq.py](/lib/bq.py)
* some functions for state-variable filters [(via Raph Levien)][svf] * some functions for state-variable filters
[(via Raph Levien)][svf]
— [svf.py](/lib/svf.py) — [svf.py](/lib/svf.py)
* sine sweeps, and the Optimized Aoshima's Time-Stretched Pulse [(via here)][sweeps] * sine sweeps, and the Optimized Aoshima's Time-Stretched Pulse
[(via here)][sweeps]
— [sweeps.py](/lib/sweeps.py) — [sweeps.py](/lib/sweeps.py)
* a lot of stuff for magnitude plotting like tilting and smoothing * basic [cepstrum][cep] utilities like minimum-phase reconstruction
— [fft.py](/lib/fft.py) [smoothfft.py](/lib/smoothfft.py) [\_\_init\_\_.py](/lib/__init__.py) [(via Julius Smith)][jos3]
— [cepstrum.py](/lib/cepstrum.py)
* rough experiments with psychoacoustic equalization ("neon pink" and other crap) * utilities for magnitude plotting, including tilting and smoothing
— [data.py](/lib/data.py) [\_\_init\_\_.py](/lib/__init__.py) — [fft.py](/lib/fft.py) [smoothfft.py](/lib/smoothfft.py) [mag.py](/lib/mag.py)
* a couple hard-coded polyphase halfband IIRs for nonlinear-phase resampling
or approximating hilbert transforms
(read more: [Olli Niemitalo][olli])
— [piir.py](/lib/piir.py)
* a dozen windowing functions and utility functions for constructing them
— [windowing.py](/lib/windowing.py)
* ad-hoc experiments with psychoacoustic equalization
("neon pink" and other crap before i realized
"grey noise" was the term i was looking for)
— [data.py](/lib/data.py)
* miscellaneous matplotlib stuff * miscellaneous matplotlib stuff
— [plot.py](/lib/plot.py) — [plot.py](/lib/plot.py)
@ -36,9 +56,12 @@ don't expect commits, docs, or comments to be any verbose.
* miscellaneous utility functions * miscellaneous utility functions
— [util.py](/lib/util.py) [wav.py](/lib/wav.py) — [util.py](/lib/util.py) [wav.py](/lib/wav.py)
[dspf]: https://github.com/vinniefalco/DSPFilters/ [dspf]: //github.com/vinniefalco/DSPFilters/
[svf]: http://nbviewer.jupyter.org/github/google/music-synthesizer-for-android/blob/master/lab/Second%20order%20sections%20in%20matrix%20form.ipynb
[sweeps]: http://www.sound.sie.dendai.ac.jp/dsp/e-21.html [sweeps]: http://www.sound.sie.dendai.ac.jp/dsp/e-21.html
[svf]: http://nbviewer.ipython.org/urls/music-synthesizer-for-android.googlecode.com/git/lab/Second%20order%20sections%20in%20matrix%20form.ipynb [cep]: //en.wikipedia.org/wiki/Cepstrum
[jos3]: //ccrma.stanford.edu/~jos/fp/
[olli]: http://yehar.com/blog/?p=368
all wrapped up in a inconveniently named "lib" module! all wrapped up in a inconveniently named "lib" module!

8
lib/cepstrum.py
View File

@ -42,15 +42,11 @@ def fold(r):
return rw return rw
def minphase(s, pad=True, os=False): def minphase(s, pad=True):
# via https://ccrma.stanford.edu/~jos/fp/Matlab_listing_mps_m.html # via https://ccrma.stanford.edu/~jos/fp/Matlab_listing_mps_m.html
# TODO: actual oversampling # TODO: oversampling
if pad: if pad:
s = pad2(s) s = pad2(s)
if os:
s = np.r_[s, np.zeros(len(s))]
cepstrum = np.fft.ifft(np.log(clipdb(np.fft.fft(s), -100))) cepstrum = np.fft.ifft(np.log(clipdb(np.fft.fft(s), -100)))
signal = np.real(np.fft.ifft(np.exp(np.fft.fft(fold(cepstrum))))) signal = np.real(np.fft.ifft(np.exp(np.fft.fft(fold(cepstrum)))))
if os:
signal = signal[:len(signal)//2]
return signal return signal