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	<563FB84C.5050403@abelian.org>
Date: Tue, 10 Nov 2015 19:09:39 +0000
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From: Andy Talbot <andy.g4jnt@gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Coherent receivers and EbNaut
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Ok.

Enhanced .WAV is ideal - no need for yet another file format.

In fact, having a redundant original header block could be useful.  If, for
example, the sampling rate value in that is programmed for, say, 1000 times
the slow rate, it might provide possibilities for playing the .WAV back as
an audio file, speeded up without extra processing

I remember doing this many years ago with Dopplergrams generated via
Motorola DSP cards, and saving I/Q data at low sampling rates in a custom
format.  The data was then upconverted and played back at a suitable sample
rate.   The Ionospheric Doppler shifted carriers, originally consisting of
many hours of recording, generated some wonderfully surreal  sounds when
played back compressed into a couple of minutes.    Some were reminiscent
of whale noises.

Andy  G4JNT

On 8 November 2015 at 21:02, Paul Nicholson <vlf0403@abelian.org> wrote:

>
> > if I publish the serial protocol, would it be feasible for
> > Ebnaut to be modified to accept the data directly?
>
> Feasible yes, but I wouldn't recommend it.   I advise
> recording the signal first, then present the recording
> to the decoder.  This, so you can repeatedly run the
> decoder with different frequency and time offsets if
> necessary in order to cope with some clock or oscillator
> offset at the transmitter, or to try a 15 deg phase
> search if the 30 deg doesn't turn anything up.
>
> You don't have to use WAV.  Define your own file format
> in which to capture your serial data, and I'll make
> ebnaut-rx handle the file when it sees a .JNT extension.
>
> Hmm, also ebnaut-tx could have an option to output
> a .JNT file, for test purposes or to drive your tx.
> --
> Paul Nicholson
> --
>
>

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<div dir=3D"ltr">Ok.<div><br></div><div>Enhanced .WAV is ideal - no need fo=
r yet another file format.</div><div><br></div><div>In fact, having a redun=
dant original header block could be useful.=C2=A0 If, for example, the samp=
ling rate value in that is programmed for, say, 1000 times the slow rate, i=
t might provide possibilities for playing the .WAV back as an audio file, s=
peeded up without extra processing</div><div><br></div><div>I remember doin=
g this many years ago with Dopplergrams generated via Motorola DSP cards, a=
nd saving I/Q data at low sampling rates in a custom format.=C2=A0 The data=
 was then upconverted and played back at a suitable sample rate. =C2=A0 The=
 Ionospheric Doppler shifted carriers, originally consisting of many hours =
of recording, generated some wonderfully surreal =C2=A0sounds when played b=
ack compressed into a couple of minutes. =C2=A0 =C2=A0Some were reminiscent=
 of whale noises.</div><div><br></div><div>Andy =C2=A0G4JNT</div></div><div=
 class=3D"gmail_extra"><br><div class=3D"gmail_quote">On 8 November 2015 at=
 21:02, Paul Nicholson <span dir=3D"ltr">&lt;<a href=3D"mailto:vlf0403@abel=
ian.org" target=3D"_blank">vlf0403@abelian.org</a>&gt;</span> wrote:<br><bl=
ockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #=
ccc solid;padding-left:1ex"><br>
&gt; if I publish the serial protocol, would it be feasible for<br>
&gt; Ebnaut to be modified to accept the data directly?<br>
<br>
Feasible yes, but I wouldn&#39;t recommend it.=C2=A0 =C2=A0I advise<br>
recording the signal first, then present the recording<br>
to the decoder.=C2=A0 This, so you can repeatedly run the<br>
decoder with different frequency and time offsets if<br>
necessary in order to cope with some clock or oscillator<br>
offset at the transmitter, or to try a 15 deg phase<br>
search if the 30 deg doesn&#39;t turn anything up.<br>
<br>
You don&#39;t have to use WAV.=C2=A0 Define your own file format<br>
in which to capture your serial data, and I&#39;ll make<br>
ebnaut-rx handle the file when it sees a .JNT extension.<br>
<br>
Hmm, also ebnaut-tx could have an option to output<br>
a .JNT file, for test purposes or to drive your tx.<br>
--<br>
Paul Nicholson<br>
--<br>
<br>
</blockquote></div><br></div>

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