--
Scilab & TclTk scripts------------------------------------------------------------
Please use these scripts in a
correct way. Give credits to the author and quote this site.
General
directions for use:
These script are
conceived for tutorial purposes. Read comments carefully
before using them, in order to clearly understand the operation.
Scilab scripts,
directions for use:
First, install
Scilab.
Decompress these
files everywhere you want.
Double-click on the
file having suffix ".sce". Scipad will open and show
the script. You can modify it, if needed.
From the scipad
menu "Execute", click on "Load into scilab".
The script will run.
Very
simple Scilab script to generate a sinusoid.
A
hopefully soft introduction to the usage of Scilab, to generate
a sinusoid.
Table oscillator.
Generate
a sinusoid both rounded or interpolated. Experiment changing the
table size
Producing
sound frames starting from single samples (something like a
precursor of granular synthesis) in Scilab.
I a frame
of 1 sec you can place pulses everywhere you want. Shows a
plot of the frame, tohether with its spectrum, and the result is
saved into a wave file. (from a suggestion of
Michelangelo Lupone.).
A
more complex Scilab script to estimate transfer functions.
Characterization
of linear systems. The stimulus in the left channel, the
response in the right channel.
The
script is interactive (from the Scilab console) and shows
the transfer function.
Click
here to download a zip file of these scripts
This
Scilab script demonstrates causal and anticausal filtering.
Relationships
between amplitude and phase of a transfer function are important
in order to achieve a causal behavior, i.e. in order for a
transfer function to be computable in actual real time. As a
further exercise, try to modify the script in order to apply to
the low-pass filter the phase of an high-pass filter, i.e.
changing the sign of the phase. [Updated 24/7/2005]
Click
here to get a zip file of the script.
A
TclTk script to plot pitch and formants in a (hopefully) useful
way.
Wavesurfer
is a very good tool for pitch-formant analysis. It has
nevertheless some limitation in showing data. Pitch is plotted in
the maximum range of 400 Hz, which is not enough for both sing and
speech, nor for musical instruments. Moreover, of formants
you can't see the bandwidth. The plot area is very small, so that
it is quite hard to get quantitative information. The
underlying TclTk package - SNACK - computes nevertheless more data
than those showed, particularly probability of voicing and
autocorrelation (for pitch), and bandwidth (for formants). In
Wavesurfer you can save this information in ASCII (text) files by
right-clicking on the corresponding pane. Pitch data are saved in
".f0" files, while formants data are saved into ".frm"
files. This script make use of these files to show pitch and
formant data in different ways. You can particularly choose the
frequency upper limit, and the linear or logarithmic (octave)
frequency scale.
Being a
script, you can open and see it using any text editor (avoid word
processors!). it is also multiplatform (Windows, Linux, Solaris,
MacIntosh). You must only have TclTk installed in your system
(tested with 8.4 version).
Click
here to download this TclTk script.
A
Scilab script which shows the four main lop-pass filters of the
first order, and related eletronic circuits.
This
script shows the Bode diagram of the four filters, which are all
causal, being them a simulation of an electronic analog actual
discrete circuit. This script makes use of the Scilab embedded
TclTk interpreter to show a figure of the corresponding electronic
circuits. So, be sure that all these three files are present in
the same folder. [Updated 24/7/2005]
Click
here to download these scripts
A
Scilab script to show the frequency response and the step response
of a resonant, 2° order damped system.
This
script lets you interactively choose the cut-off (resonant)
frequency and the damping factor. It shows the Bode plot and the
step response of the system. This script makes use of the Scilab
embedded TclTk interpreter to show a figure of a corresponding
electronic circuit. So, be sure that all these two files (script
and figure) are present in the same folder.
Beware: for unknown reasons, this script runs very slow (it uses a
lot of CPU time) in version 3.1.1. It works fine under version 3.0
instead. [Updated 24/7/2005]
Click
here to get a zip of these files.
A
simple Scilab Script to illustrate the convolution with an Impulse
Response.
This Scilab
script allows - even if in a quite rude way - the convolution of
short sounds (few tenths of seconds) with an Impulse Response. You
can in this way for instance ear your sound as it would be
heard in a Concert Hall or a Theatre. Impulse Response of
Theatres, Churches and Concert Halls as well as anechoic sounds
are available on the Internet, here
for instance (thanks to Angelo Farina). As usual, read the
comments before use [Updated 24/7/2005].
Click
here to download the script
Scilab Script to show two Sonic
Visualiser features files superimposed on the same plot.
You can load a couple of ASCII files coming from feature
analysis and see them as two superimposed curves on the same
plot. Let follow the comments to further personalize the script.
Click
here to download the script
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