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The STiD135 is an amazing chip. The last time I checked they weren't interested in talking to anyone that didn't have a huge requirement. That may have changed. DVB-S2x also supports down to 5% rolloff.<br>
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Howie AB2S<br>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Ground-Station <ground-station-bounces@lists.openresearch.institute> on behalf of Ron Economos via Ground-Station <ground-station@lists.openresearch.institute><br>
<b>Sent:</b> Saturday, August 24, 2019 9:30:09 AM<br>
<b>To:</b> ground-station@lists.openresearch.institute <ground-station@lists.openresearch.institute><br>
<b>Subject:</b> Re: [Ground-station] DVB-S2 or -X bandwidth ?</font>
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<div class="PlainText">It used to be that demodulator chips didn't go below 1 Msym/s, but more
<br>
recent chips do. On QO-100, folks are using 500 and 333 ksym/s and even <br>
lower. The STiD135 that I posted about previously is specified down to <br>
100 ksym/s.<br>
<br>
The actual bandwidth of a DVB-S2 signal is the symbol rate times the <br>
roll-off factor + 1. The typical roll-off used is 0.2, so a 1 Msym/s <br>
signal is 1.2 MHz wide. A 1 MHz bandwidth would require a 833 ksym/s signal.<br>
<br>
Ron W6RZ<br>
<br>
On 8/24/19 05:49, KC9SGV via Ground-Station wrote:<br>
> Hi All,<br>
> Is 1 MHz wide enough for DVB-S2 transmissions ?<br>
> I cannot attach a picture here, but look on page 17 of this old TAPR paper.<br>
> Seems like 2 MHz is the minimum bandwidth required ?<br>
><br>
> <a href="https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.tapr.org%2Fpdf%2FDCC2009-DATV-KB6CJZ-W6HHC.pdf&data=02%7C01%7C%7Cb8f5db9595734bb3f39008d7289802a9%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637022505662404251&sdata=YCKEQI2f%2Bhjk374WaNG8gxIiKCyL%2FLYChSGocDRLwNQ%3D&reserved=0">
https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.tapr.org%2Fpdf%2FDCC2009-DATV-KB6CJZ-W6HHC.pdf&data=02%7C01%7C%7Cb8f5db9595734bb3f39008d7289802a9%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637022505662404251&sdata=YCKEQI2f%2Bhjk374WaNG8gxIiKCyL%2FLYChSGocDRLwNQ%3D&reserved=0</a><br>
><br>
> Maybe only legacy ham Linear modes will be supported by our 1 MHz Rent-a- GEO effort ?<br>
><br>
> Bernard,<br>
> KC9SGV<br>
><br>
><br>
> Sent from my iPad<br>
><br>
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