[Spooks] XSL Question

[Leif Dehio]

At 09:24 29.10.2011, you wrote:
>Thanks very much Leif,
>
>Is it a PSK waveform while idle, or just when transmitting data, or both?
>
>The idling sound pattern is what is intriguing to me, and it got me
>thinking about it being a radar, or something else that act similarly.
>I've heard the data sound pattern and it does sound exactly like STANAG
>4285 data transmissions as you mention.  However, the chop-chop part of
>the idle sound seems remarkably like the Russian "woodpecker" and other
>OTH radars I've heard.  It didn't seem beyond possibility that the
>additional tone patterns were laid on top of (or interleaved with) the
>"chop-chop" part, and I was curious about it.
>
>There are lots of examples of signals embedded, or interleaved with other
>signals which are then later stripped out.  X10 devices might be a good
>example, which use signalling over the 110v AC power lines.  Another
>example might be IP over AC power lines.
>
>I'm very new to this, so I'm sure this has been brought up before and
>dismissed for various reasons.  I just couldn't find any discussion about
>it in my Google searches.
>
>Thanks again,
>Mike


Hi Mike,

the station sends 1500 Bd QPSK also in it's idle state.
I suppose the additional tone frequencies that are visible
when the station is in idle mode, are used to synchronize
and align the modems on the remote side.

Some basic info on the waveform can be found here:

http://www.signals.taunus.de/FFT/J-NY_1500Bd_QPSK.HTML

BRGDS

//Leif


and  during the



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