<div dir="ltr">To me, decimation is what we do in order to channelize in the payload. <br><br>I don't think that's exactly what I'm being asked about in the ground station receiver, though. <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 4:14 PM Ron Economos <<a href="mailto:w6rz@comcast.net">w6rz@comcast.net</a>> 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>I'm not sure we are talking about the same thing yet. So what
exactly do you expect to decimate and why?<br>
</p>
<p>Ron W6RZ<br>
</p>
<div class="gmail-m_8520444453280004698moz-cite-prefix">On 1/25/19 16:07, Michelle Thompson
wrote:<br>
</div>
<blockquote type="cite">
<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-m_8520444453280004698gmail_signature">
<div dir="ltr">
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<div dir="ltr">
<div dir="ltr">-Michelle W5NYV<br>
<br>
<div dir="ltr"><br>
</div>
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<div dir="ltr" class="gmail-m_8520444453280004698gmail_attr">On Fri, Jan 25, 2019 at 3:52
PM Ron Economos via Ground-Station
<a class="gmail-m_8520444453280004698moz-txt-link-rfc2396E" href="mailto:ground-station@lists.openresearch.institute" target="_blank"><ground-station@lists.openresearch.institute></a> 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">
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<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_8520444453280004698gmail-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_8520444453280004698gmail-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_8520444453280004698gmail-m_-6643074664132559776ydp1f38d99eyahoo-style-wrap">
<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_8520444453280004698gmail-m_-6643074664132559776ydp40e62e6byahoo_quoted_8708381549" class="gmail-m_8520444453280004698gmail-m_-6643074664132559776ydp40e62e6byahoo_quoted">
<div>
<div> On Friday, January 25, 2019, 2:41:54 PM PST,
Michelle Thompson via Ground-Station <a class="gmail-m_8520444453280004698gmail-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_8520444453280004698gmail-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_8520444453280004698gmail-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>
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</div>
</div>
</div>
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