Pulsar Central


Pulsars are rapidly rotating neutron stars which sweep out a beam of electromagnetic radiation like a light house.  These exotic stars were only discovered in the late 1960's when their pulsing signatures were found by then graduate student Jocelyn Bell Burnell when searching miles of radiotelescope strip charts for signals of a different type.  

 

It is possible for amateur radio astronomers to detect some of the stronger pulsars by use of digital signal processing techniques given an adequate gain antenna.However this is a project best pursued after gaining considerable experience. One trick derives from knowing the period of the pulsar in advance. We then sample the signal using a time base that is some integral fraction of the period. Each sample taken during the duration of a single pulse period is assigned to a bin.  The samples can then be folded back so that samples from corresponding bins are added together.

 Each time we add a new series of bin values for the ongoing totals, we "renormalize" by subtracting an an amount from all of the bins so that the weakest bin value is brought back to zero. Random noise in each bin tends to average out and bins which have even slightly higher averages will gradually "grow" above the others. A picture then emerges which shows how the average strength of the pulsar signal varies over it's period.  

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The following links to .WAV files will allow you to hear the audio frequency modulation of radio noise generated by pulsars. If your .WAV file player has a scope function on it you will be able to see the regular nature of the waveforms. These files are quite long (some close about .5 meg).

PSR 0329+54


PSR 0950+08


PSR 0833 (Vela Pulsar)


CP0834 (very faint... for fun, try DSP on this one).


Pulsar Links

European Pulsar Network Data Archive

USNO Pulsar Data Archive

Jodrell Bank Pulsar Page

What is a Pulsar?

 

Oleg Doroshenko has free timing and catalog software for pulsars.


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