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Date: Fri, 6 Mar 2009 20:13:32 +0000
Message-ID: <fc7eccec0903061213s74f81514xdfdbe7318968bf74@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: Multi-function beacon
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Not strictly -
Look at it in th efreqeuncy domain.  A 500us pulse has its first zero at
2000/pi = 637Hz, so most of the energy is within 1300Hz bandwidth, and a
substantial part will pass though the Rx filter.  It will be extended in
time and flattenned, but the detection algorithm finds the peak, in effect
applying an inverse transform of the SSB filter.

Andy  G4JNT
www.g4jnt.com


>
> Nb   the  pulse width , 500uS .. that's a bit  sharp for a ssb filter ,
> only  1.5 cycles at 3 Khz ... ?
>
>
>
>
>

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<div>Not strictly - </div>
<div>Look at it in th efreqeuncy domain.=A0 A 500us pulse has its first zero=
 at 2000/pi =3D 637Hz, so most of the energy is within 1300Hz bandwidth, and=
=A0a substantial part will pass though the Rx filter.=A0 It will be extended=
 in time and flattenned, but the detection algorithm finds the peak, in effe=
ct applying an inverse transform of the SSB filter.</div>

<div><br clear=3D"all">Andy =A0G4JNT<br><a href=3D"http://www.g4jnt.com">www=
.g4jnt.com</a><br><br></div>
<div class=3D"gmail_quote">
<blockquote class=3D"gmail_quote" style=3D"PADDING-LEFT: 1ex; MARGIN: 0px 0p=
x 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div style=3D"PADDING-RIGHT: 10px; PADDING-LEFT: 10px; PADDING-TOP: 15px" na=
me=3D"Compose message area">
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2">Nb =A0 the=A0 pulse width , 500uS .. th=
at&#39;s a bit=A0 sharp for a ssb filter , only=A0 1.5 cycles at 3 Khz ... ?=
</font></div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div style=3D"FONT: 10pt Tahoma">=A0</div></div></blockquote></div>

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