Best wishes to you All,
To explain to my girlfriend and our children some more about pulsars, I decided to take our captured data and add a visual and audio interpretation of the pulsar.
From the period data 100 to 545 (fig1) we took the short range 100 to 200 periods; fig 2.
Next we selected periods 100 to 200 of the datastream and folded/added it in real time every period. You can see in the video that the pulse is rising from the noise. At the same time the peak above a certain level will generate a tone. This tone can also be so low in frequency that it gives the 'thumb' sound of a pulsar. The background sound can be set to a loud noise sound level or it can be set to attenuate completely.
The total presentation time is 100 periods of the B0329+54 pulsar, so about a minute.
Configuration is done with the Ap.cfg file; it contains the following:
0.------pulsar audio folding------------
1.pulsar name = B0329 SGRT
2.pulsar period time [s]=0.71463071463
3.spectrum file name without extension=z-100bt
4.fold period from =100
5.fold period to =205
6.audio pulse squelch level (0..1)=0.998
7.audio noise volume (0..1)=0.1
The tones were generated with an online tool from
Also we ripped sound from a youtube track with Audacity (first time for me).
We used the python pygame modules to handle the sounds. To run the python script you need pygame installed; see
More specific info:
The data captured in this session had a lot of RFI (Radio Frequency Interference ). Later we could trace that back to the LAN (Local Area Network) cables.
The source period files or spectrum files were generated by the 3pt-calc.exe program. Each file consists of a number of spectra for each bin range and one sum spectrum bin range. The sum of the spectra is also available in the sum bins (nr 10 or nr 20). The latest 3pt calc program splits the spectrum into 20 channels.
This audio script is loading the successive period files and scans the bins for the maximum value. Next it scans again to flag every bin with an amplitude higher than the squelch level. This flagged bin will generate an audio tone.
In the right side monitor window of 'spider' you can see info of each period.
The first value is the period number (from 100 to 200).
The second value is the bin number of the maximum found amplitude. In the beginning the bin numbers vary, but later, from period 130, the bin number is the stable number 65.
The third value is the period time of the audio period.
The horizontal line is the squelch level; noise can be heard when the amplitude rises above this level.
The video on youtube (first time for me) can be seen here:
A second video shows the same folding, but now the individual periods are also shown in red.
The amplitude of the individual period is actually 4 times larger, but in the graph reduced for clarity.
In preview the movie screen resolution is good, but via youtube it seems to reduce and also fullscreen does not work for me. But perhaps I have a lot to learn.
We have to find out how to minimize the size of the converted py script to an executable. At the moment it is huge (1GB).When it has a reasonable size, then it will be available here also.
This project is also added to the project list (nr 17) of the parac site.