[Laser] Mystery Modulated Light

[MICHAEL COUTURE]

Hi Steve & Group,

I don't know if it has been suggested before but there is a FREE audio spectrum program that will look at signals in the dirt all the way up to kHz range. Here's the url:
http://www.weaksignals.com/

It's called Spectran and works GREAT. Just download and install it. Hope that helps.

Mike C.

--- On Sat, 6/30/12, steve kavanagh <skavanagh73 at yahoo.ca> wrote:

From: steve kavanagh <skavanagh73 at yahoo.ca>
Subject: [Laser] Mystery Modulated Light
To: laser at mailman.qth.net
Date: Saturday, June 30, 2012, 6:14 PM

There's not a whole lot to record....it sounds just like a constant frequency tone.  My receiver has significant rolloff above 2 kHz, so the harmonics I hear are probably at lower levels than in the raw signal.  But it might be worth taking a look with an oscilloscope at the receiver output instead of a spectrum analyzer, to see what the waveform is like (duty cycle of pulse, or is it a triangle wave, etc.).

I agree with Stuart that most of the LED drivers I have seen data sheets for operate above 30 kHz.  I did see one that was FM-ed at a 1 kHz rate to minimize EMC spectral density problems.  

Maybe there is someone running a beacon with no ID !

73,
Steve VE3SMA


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