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<DIV style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif">I see some UDP packet performance issues in my laptop (but not in my desktop computer). Will the common (interleave multiple receives) UDP link helps?<BR><BR>The issue is that fread for the second dongle in matlab get less data than expectation sometimes. Seem that fread for the first dongle works well.</DIV></DIV>
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<SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif; FONT-WEIGHT: bold">From: </SPAN><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif"><A href="mailto:sdrguru1@gmail.com">Sdr Guru</A></SPAN><BR><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif; FONT-WEIGHT: bold">Sent: </SPAN><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif">2014/1/2 5:39</SPAN><BR><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif; FONT-WEIGHT: bold">To: </SPAN><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif"><A href="mailto:osmocom-sdr@lists.osmocom.org">osmocom-sdr@lists.osmocom.org</A></SPAN><BR><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif; FONT-WEIGHT: bold">Subject: </SPAN><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: Calibri,sans-serif">Re: How to get IQ samples from multiple rtl-sdr dongles in asynchronized manner?</SPAN><BR><BR></DIV>
<DIV dir=ltr>Hi
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<DIV>rtl-sdr-relay<BR></DIV>
<DIV>Some of the recommendations.<BR></DIV>
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<DIV>Please add PPM error calculation, exactly like new rtl_test -p but multiple receivers simultaneously.</DIV></DIV>
<DIV>It provides immediate information if something is wrong with USB or dongles.<BR></DIV>
<DIV><A href="https://github.com/keenerd/rtl-sdr/commit/b5f89dcf40463130e717b6c9bb3a39a3c8b9535f">https://github.com/keenerd/rtl-sdr/commit/b5f89dcf40463130e717b6c9bb3a39a3c8b9535f</A><BR></DIV>
<DIV><A href="https://github.com/keenerd/rtl-sdr/blob/master/src/rtl_test.c">https://github.com/keenerd/rtl-sdr/blob/master/src/rtl_test.c</A><BR></DIV>
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<DIV>Please add automatic eeprom PPM calibration</DIV>
<DIV><A href="https://github.com/keenerd/rtl-sdr/commit/ecf267737ca52f5005b7a12a352307e8cd763ed6">https://github.com/keenerd/rtl-sdr/commit/ecf267737ca52f5005b7a12a352307e8cd763ed6</A><BR></DIV>
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<DIV>default sample rate 2.4M (28.8/12) or 1.2M (28.8/24), probably lower jitter</DIV>
<DIV>MAX_NUM_DEV 4->16 :)<BR></DIV>
<DIV><BR></DIV>
<DIV>Some nice to have features.<BR></DIV>
<DIV>ip binding<BR></DIV>
<DIV>multicast support<BR></DIV>
<DIV class=gmail_extra>one common (interleaved) stream of all the receivers</DIV>
<DIV class=gmail_extra>timestamped stream</DIV>
<DIV class=gmail_extra><BR></DIV>
<DIV class=gmail_extra>I'm trying to convert MATLAB script to Ocatve.<BR></DIV>
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<DIV class=gmail_extra>SG<BR><BR>
<DIV class=gmail_quote>On Mon, Dec 30, 2013 at 9:38 AM, Jiao Xianjun <SPAN dir=ltr><<A href="mailto:putaoshu@gmail.com" target=_blank>putaoshu@gmail.com</A>></SPAN> wrote:<BR>
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<DIV>Hi guys,<BR><BR></DIV>For the multiple dongles synchronization in signal level instead of bits/packets level, I setup a working repo in github, and write a initial demo framework. See below:<BR><BR><A href="https://github.com/JiaoXianjun/multi-rtl-sdr-udp-relay.git" target=_blank>https://github.com/JiaoXianjun/multi-rtl-sdr-udp-relay.git</A><BR><BR></DIV>You may find information and instruction of demo quickly by reading the README.<BR>
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<P style="WHITE-SPACE: normal; TEXT-TRANSFORM: none; WORD-SPACING: 0px; COLOR: rgb(51,51,51); FONT: 15px/25px Helvetica,arial,freesans,clean,sans-serif; MARGIN: 15px 0px; LETTER-SPACING: normal; TEXT-INDENT: 0px">My initial purpose is performing in-fly calibration for multiple dongles according to some pre-known signal (GSM, ADS-B?) to let them work together coherently.</P>
<P style="WHITE-SPACE: normal; TEXT-TRANSFORM: none; WORD-SPACING: 0px; COLOR: rgb(51,51,51); FONT: 15px/25px Helvetica,arial,freesans,clean,sans-serif; MARGIN: 15px 0px; LETTER-SPACING: normal; TEXT-INDENT: 0px">An ideal scheme may be that we should generate a very narrow band and very week signal in (or just located at the edge of) target working band of dongles, and perform the software in-fly calibration in background (or driver level). This would be user friendly.<BR></P>
<P style="WHITE-SPACE: normal; TEXT-TRANSFORM: none; WORD-SPACING: 0px; COLOR: rgb(51,51,51); FONT: 15px/25px Helvetica,arial,freesans,clean,sans-serif; MARGIN: 15px 0px; LETTER-SPACING: normal; TEXT-INDENT: 0px">I know it is far from final state currently, and many things are not clear yet (See TODO). But please join me if you also think this is a good idea. Just check out the demo and run it to have a look.</P>
<P style="WHITE-SPACE: normal; TEXT-TRANSFORM: none; WORD-SPACING: 0px; COLOR: rgb(51,51,51); FONT: 15px/25px Helvetica,arial,freesans,clean,sans-serif; MARGIN: 15px 0px; LETTER-SPACING: normal; TEXT-INDENT: 0px">Currently I just test the demo in Ubuntu-Linux.</P>
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<P style="WHITE-SPACE: normal; TEXT-TRANSFORM: none; WORD-SPACING: 0px; COLOR: rgb(51,51,51); FONT: 15px/25px Helvetica,arial,freesans,clean,sans-serif; MARGIN: 15px 0px; LETTER-SPACING: normal; TEXT-INDENT: 0px">BR</P><SPAN><FONT color=#888888>
<P style="WHITE-SPACE: normal; TEXT-TRANSFORM: none; WORD-SPACING: 0px; COLOR: rgb(51,51,51); FONT: 15px/25px Helvetica,arial,freesans,clean,sans-serif; MARGIN: 15px 0px; LETTER-SPACING: normal; TEXT-INDENT: 0px">Jiao Xianjun<BR></P></FONT></SPAN></DIV></DIV>
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