Image:Triangle1000 spectrum.png

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Triangle1000_spectrum.png‎ (800 × 600 pixels, file size: 4 KB, MIME type: image/png)

[edit] Summary

Spectrum analysis of the uncompressed source for 5 seconds of triangle wave at 1000 Hz (help·info). Note the logarithmic frequency scale. The y-range of this graph may not be appropriate for comparison of similar waveforms; it is designed to match the frequency spectrum graphs for audio noises on Colors of noise.

The analysis was done using Audacity, and plotting with gnuplot. Transparency was touched up in GIMP to make the graph background pure white.

[edit] Instructions

Obtain the frequency analysis from Audacity, set the maximum number of windows, and use a Hamming window. The following script was used to generate the image:

set terminal png transparent font "/usr/share/fonts/truetype/ttf-bitstream-vera/Vera.ttf" size 800,600 enhanced
set output "triangle1000_spectrum.png"

# this seems to fix the trailers on the TTF font for the x-label
set bmargin 4

# enable grid
set grid
set grid mxtics

# set up x-axis
set logscale x 10
set xrange [100:22000]
set xlabel "Frequency (Hz)"
set xtics border nomirror

# set up y-axis
set yrange [-40:0]
set ylabel "Intensity (dB)"
set ytics border nomirror

# again to deal with bad bboxes on the TTF...
# here also avoid the graph
set key left height 1 box

# plot the output from Audacity
plot "triangle1000.txt" title "1KHz Triangle Wave" with filledcurves x1 3

[edit] Licensing

I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide.

In case this is not legally possible,

I grant any entity the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

File history

Click on a date/time to view the file as it appeared at that time.

	Date/Time	Dimensions	User	Comment
current	01:53, 14 March 2006	800×600 (4 KB)	Ktims (Talk \| contribs)	(Spectrum analysis of the uncompressed source for {{Audio\|Triangle_wave_1000.ogg\|5 seconds of triangle wave at 1000 Hz}}. Note the logarithmic frequency scale. The analysis was done using Audacity, and plotting with gnuplot. Transparency was touch)