To: rsgb_lf_group@blacksheep.org
From: dl4yhf@freenet.de
User-Agent: freenetMail
MIME-Version: 1.0
Message-Id: <E1NuNl6-0006Wa-4e@www20.emo.freenet-rz.de>
Date: Wed, 24 Mar 2010 11:24:20 +0100
Subject: Re: LF: Re: DK7FC's 3rd VLF transmission
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: quoted-printable
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org


Hi Jim,

you asked:
For this reason, the filter was added to
>=20
> reduce the level of the powerful VLF utilities, and the lower frequency=
=20
> mains noise, and TV line timebases etc., in the sound card input signal.=
 I=20
> think it should be possible to configure Spectrum Lab to do the necessar=
y=20
> filtering, along with limiting and FFT, but I have not yet been able to=
 get
>=20
> it to do all this at the same time as a high resolution complex FFT cent=
ered
>=20
> on 9kHz - perhaps Wolf could comment?
>=20

Yes, that's possible. There are various noiseblankers which can be include=
d in the signal path before the analyser.=20
The most simple one is in each "DSP blackbox" (the square objects labelled=
 with a question mark).=20
I think Markus has already used them to defeat QRN with some success.

BTW The "soundcard sampling rate calibrator" has been modified in SL V2.75=
 b6 .  It has an immediate effect now, after entering a reference frequenc=
y, and the measured frequency. For the next release, the 'continuous' samp=
le rate calibrator will support synchronizing to the ALPHA beeps; I am sti=
ll working on that (either with a boxcar integrator, or with a sufficientl=
y narrow-band detector).


Cheers,
  Wolf .





Unbegrenzter Speicher, Top-Spamschutz, 120 SMS und eigene E-MailDomain ink=
l.
http://office.freenet.de/dienste/emailoffice/produktuebersicht/power/mail/=
index.html