<div dir="ltr">The beginning of wisdom being the definition of terms and all, it would be good to make sure we're all talking about the same thing. <br><br>So far, I've used LNBs and USRPs for receive, with the LNB doing an IF at 618MHz (LNB-on-a-Stick) and giving reasonable performance. <br><br>Decimation to me is a DSP thing, or used to reduce power consumption when you don't need to sample as high as you can. <br><br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr">-Michelle W5NYV<br><br><div dir="ltr"><br></div></div></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jan 25, 2019 at 3:52 PM Ron Economos via Ground-Station <ground-station@lists.openresearch.institute> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF">
<p>The standard IF for DVB-S2 receivers is 950 to 2150 MHz.</p>
<p>DB6NT was selling a down-converter from 10489-10500 MHz to
1129-1140 MHz for P4A.</p>
<p><a class="gmail-m_-6643074664132559776moz-txt-link-freetext" href="https://shop.kuhne-electronic.com/kuhne/en/shop/new/MKU+LNC+10+OSCAR+P4A/?card=1832" target="_blank">https://shop.kuhne-electronic.com/kuhne/en/shop/new/MKU+LNC+10+OSCAR+P4A/?card=1832</a></p>
<p>I'm not sure what decimation has to do with receiving DVB-S2. The
entire 10 MHz signal needs to be demodulated. Individual baseband
frames will be selected for processing, but I call that
de-multiplexing.<br>
</p>
<p>Ron W6RZ<br>
</p>
<div class="gmail-m_-6643074664132559776moz-cite-prefix">On 1/25/19 15:32, David Vieira via
Ground-Station wrote:<br>
</div>
<blockquote type="cite">
<div class="gmail-m_-6643074664132559776ydp1f38d99eyahoo-style-wrap" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:13px">
<div>Michelle - Thanks for posting. I'll frame some of the
questions.<br>
</div>
<div><br>
</div>
<div>Typical 10 GHz terrestrial contesting rigs are Heterodyne;
that is a Mixer works with a Local Oscillator (LO) to take the
RF down to an IF (Intermediate Frequency).</div>
<div>For an SDR, that IF can be digitized by an Analog-Digital
Converter.</div>
<div><br>
</div>
<div>The most popular IF for contesting/SSB rigs is 144 MHz. </div>
<div>For a data BW of 10 MHz that may or may not be a fast
enough IF carrier. If we can digitize and recover the data,
it would allow a lot of re-use of existing equipment.</div>
<div><br>
</div>
<div>I've heard suggestions/proposals up to the 1.2 GHz Ham
band.</div>
<div>In some sense, the IF carrier could be 144/220/440/915/1200
MHz, or even any Non-Ham frequency in between.</div>
<div><br>
</div>
<div>There are a lot of proof of existence designs for a 10 GHz
Mixed down to an IF; and lots of off the shelf ADC
dev-boards. (catch me off thread for details).</div>
<div><br>
</div>
<div>Some questions I have are: </div>
<div>---from an FPGA side of the SDR, what data rate(s) can the
FPGA absorb in to a decimator? </div>
<div><br>
</div>
<div>Must we decide upfront on a single frequency; or </div>
<div>preferably allow flexibility in the RF front end design
(ie, Mixer, PLL and Local Oscl hardware choices) by allowing a
wide and programmable variety of ADC and decimation rates?</div>
<div><br>
</div>
<div>{This is where RF and Digital folks must communicate across
walls.} ;-)</div>
<div><br>
</div>
<div>Comments welcome.</div>
<div><br>
</div>
<div>regards,</div>
<div>David</div>
<div>KI6CLA</div>
<div><br>
</div>
<div><br>
</div>
</div>
<div id="gmail-m_-6643074664132559776ydp40e62e6byahoo_quoted_8708381549" class="gmail-m_-6643074664132559776ydp40e62e6byahoo_quoted">
<div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:13px;color:rgb(38,40,42)">
<div> On Friday, January 25, 2019, 2:41:54 PM PST, Michelle
Thompson via Ground-Station
<a class="gmail-m_-6643074664132559776moz-txt-link-rfc2396E" href="mailto:ground-station@lists.openresearch.institute" target="_blank"><ground-station@lists.openresearch.institute></a> wrote: </div>
<div><br>
</div>
<div><br>
</div>
<div>
<div id="gmail-m_-6643074664132559776ydp40e62e6byiv6388574106">
<div dir="ltr">
<div dir="ltr">While we are striving to enable all sorts
of wonderful designs by putting prototypes into GNU
Radio, a central goal is to design our own hardware.<br>
<br>
We've had a lot of progress on the protocol and
algorithm front (GSE, LDPC, some of the polyphase). <br>
<br>
Some fundamental decisions about our own hardware need
to be made.<br>
<br>
When we receive, we expect to have to decimate. This
is because we are receiving at a relatively high
frequency (10GHz).<br>
<br>
Our bandwidth is (up to) 10MHz. For DVB-S2/X, we fix
our sampling rate, depending on what bandwidth we want
to support. We have a lot of freedom here.<br>
<br>
Picking the right frequencies for the receive chain is
therefore important.<br>
<br>
What are our options? <br>
<br>
What options make the best sense?<br>
<br>
I'd like to build and test as soon as possible, so
let's get some discussion going.<br>
<br>
<div>
<div dir="ltr" class="gmail-m_-6643074664132559776ydp40e62e6byiv6388574106gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div dir="ltr">-Michelle W5NYV<br>
<br>
<div dir="ltr"><br>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
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