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List: gnuradio-discuss
Subject: =?gb18030?B?u9i4tKO6ILvYuLSjuiC72Li0o7ogUHJvYmxlbXMg?= =?gb18030?B?aW1wbGVtZW50aW5nIFVTUlAgYjIxMCBkd
From: "=?gb18030?B?xNzK6cTc0dQ=?=" <2127629883 () qq ! com>
Date: 2022-12-21 9:21:39
Message-ID: tencent_1AB52AA3855D50B41AC1465DC5ABACC9E90A () qq ! com
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Sorry I forgot to put the file
------------------ ÔʼÓʼþ ------------------
·¢¼þÈË: \
"ÄÜÊéÄÜÑÔ" \
<2127629883@qq.com>; ·¢ËÍʱ¼ä: 2022Äê12Ô 21ÈÕ(ÐÇÆÚÈý) Ï Îç5:18
ÊÕ¼þÈË: "Marcus \
M¨¹ller"<mueller@kit.edu>;"discuss-gnuradio"<discuss-gnuradio@gnu.org>;
Ö÷Ìâ: »Ø¸´£º »Ø¸´£º »Ø¸´£º Problems implementing USRP b210 dual channel \
transceiver
Hi,
I'm sorry that I was delayed last week. I conducted some experiments \
again (test_tx, test_rx in the attachment). I found that the two signals have been \
successfully separated under this setting and will not interfere with each other. \
Therefore, I believe that the cause of high bit error rate may be somewhere else. The \
other two GRCs in the attachment are what I want to achieve. I found this phenomenon: \
I removed one of the "FEC extended decoders" on the receiving end (rx), \
and the other one performed very well. However, as long as the two "FEC extended \
decoders" modules existed at the same time, the bit error rate would become extremely \
high. I don't know what happened. I also didn't get a detailed explanation about this \
module from the official website. Best Regards,
linge93
------------------ ÔʼÓʼþ ------------------
·¢¼þÈË: \
"Marcus M¨¹ller" \
<mueller@kit.edu>; ·¢ËÍʱ¼ä: 2022Äê12Ô 8ÈÕ(ÐÇÆÚËÄ) ÍíÉÏ6:23
ÊÕ¼þÈË: "discuss-gnuradio"<discuss-gnuradio@gnu.org>;
Ö÷Ìâ: Re: »Ø¸´£º »Ø¸´£º Problems implementing USRP b210 dual channel transceiver
On 12/7/22 13:49, ÄÜÊéÄÜÑÔ wrote:
> The number of data packets in ¢Ù is not correct, but the number of \
> data packets in ¢Ú is correct. Therefore, to avoid more problems, I
> choose ¢Ú.
You were probably operating on a different frequency than you've thought!
> By viewing the pictures in the attachment and your explanation, f_ RF
> is LO frequency? Then the two channels share one LO, so setting f_
> Offset adjusts the frequency to f_ target?
Exactly!
> I tried the following:
> freq1= 2.4G
> freq2= 2.39G
> lo_off1= 5M
> lo_off2= -5M
> samp_rate=300K
> But the problem still exists, and the bit error rate is very high \
: ( well, there might be many reasons for that; one might be that the
sampling rate of 300 kHz is very low for the USRP, so filtering might be
suboptimal.
> Another thing I forgot to say is that I did a dual channel
> transmission experiment before (I call it experiment A. ), and the
> parameter settings are the same as when I first set them£¨freq1 = 2.4G,
> freq2=2.39G, lo_off1=2M, lo_off2=-2M,samp_rate=300k£©,which performs
> very well.
But you cannot have been operating on the frequencies you thought you
were using, so that success is a bit meaningless?
Best regards,
Marcus
> The only difference between experiment A and this experiment now is
> that the modulation of the signals on the RFA and RFB of experiment A
> are different. I copied the USRP sink and USRP source components
> directly from the GRC of experiment A, and the parameter settings are
> the same, experiment A performed very well, but in this experiment a
> high BER occurred, so now I am confused where the problem lies
> Best regards£¡
>
>
> ------------------ ÔʼÓʼþ ------------------
> *·¢¼þÈË:* "Marcus M¨¹ller" <mmueller@gnuradio.org>;
> *·¢ËÍʱ¼ä:* 2022Äê12Ô 7ÈÕ(ÐÇÆÚÈý) Ï Îç5:37
> *ÊÕ¼þÈË:* "discuss-gnuradio"<discuss-gnuradio@gnu.org>;
> *Ö÷Ìâ:* Re: »Ø¸´£º Problems implementing USRP b210 dual channel
> transceiver
>
> Sorry, typo, hit ctrl-enter to send accidentally when trying to fix
> it. Let me say it
> correctly:
>
> Re: ¢Ù But you receive packets! So that's a good thing, I guess?
>
> Re: ¢Ú So, maybe the attached figure helps. The offset is the
> difference between the
> physical LO frequency f_{RF}, and the center frequency of what becomes
> your baseband.
>
> So, I incorrectly said "the offsets need to add up to 10 MHz"; correct
> would be to say that
> freq1-offset1 = freq2-offset2.
> Now, since freq2 = freq1 - 10 MHz follows
> freq1-offset1 = freq1 - 10 MHz - offset2
> 10 MHz = offset1 - offset2
>
> Note that offsets can be negative.
>
> Best regards,
> Marcus
>
> On 07.12.22 10:30, Marcus M¨¹ller wrote:
> > Your LO offset still don't add up to the difference between freq1
> and freq2. What
> > frequency is the physical LO supposed to have? It cannot have
> frequency 2.4 GHz - 5 MHz
> > and 2.39 + 2 MHz at the same time. These are different numbers!
> >
> > Best regards,
> > Marcus
> >
> > On 07.12.22 09:09, ÄÜÊéÄÜÑÔ wrote:
> >> Hi,
> >> Thank you for your reply, based on your suggestion \
I have > tried the following:
> >> ¢ÙNo LO offset set (no uhd.tune_request)
> >> Ch0:Center Freq : freq1
> >> Ch1:Center Freq : freq2
> >> £¨freq1 = 2.4G, \
freq2=2.39G,samp_rate=300k£© > >> ¢ÚSet LO Offset
> >> Ch0:Center Freq : \
uhd.tune_request(freq1,lo_off1) > >> \
Ch1:Center Freq : uhd.tune_request(freq2,lo_off2) > >> \
£¨freq1 = 2.4G, freq2=2.39G, lo_off1=5M, > \
lo_off2=5M,samp_rate=300k£© > >> or £¨freq1 = \
2.4G, freq2=2.396G, lo_off1=2M, > lo_off2=2M,samp_rate=300k£©
> >> or £¨freq1 = 2.4G, freq2=2.396G, lo_off1=2M,
> lo_off2=-2M,samp_rate=300k£©
> >>
> >> for ¢Ù£º
> >> In this case, the number of packets received is \
incorrect and > the problem becomes
> >> more serious.
> >> for ¢Ú£º
> >> In this case the BER is still very high (I don't \
think it's my > system because the
> >> transmit power is set to 1 (Normalized) and the BER is quite low
> when using one RF
> >> channel, but I still think I'm using the USRPB210's dual channel
> transmission mode
> >> incorrectly)
> >> Best Regards£¡
> >>
> >> ------------------ ÔʼÓʼþ ------------------
> >> *·¢¼þÈË:* "Marcus M¨¹ller" <marcus.mueller@ettus.com>;
> >> *·¢ËÍʱ¼ä:* 2022Äê12Ô 6ÈÕ(ÐÇÆÚ¶þ) ÍíÉÏ8:49
> >> *ÊÕ¼þÈË:* "discuss-gnuradio"<discuss-gnuradio@gnu.org>;
> >> *Ö÷Ìâ:* Re: Problems implementing USRP b210 dual channel transceiver
> >>
> >> There's only one physical TX LO; so either you just don't specify
> offsets, OR they must
> >> add up to the difference between the two target frequencies.
> >>
> >> In your case, the difference is 10 MHz, but your offsets don't add
> up to 10 MHz, and
> >> you're requesting something impossible.
> >>
> >> Best regards,
> >> Marcus
> >> On 06.12.22 12:45, ÄÜÊéÄÜÑÔ wrote:
> >> > Hi,
> >> > I am using OFDM + USRPB210 for data \
transmission. I am > using two USRPB210s, one
> >> being
> >> > used as a transmitter and the other as a receiver. When I \
use > only one of the channels
> >> > (RFA or RFB) the data can be transmitted properly. I needed \
to > transmit two different
> >> data
> >> > at the same time, so I used both the USRP RFA and RFB. the
> baseband processing part
> >> of the
> >> > link was the same for both channels (including channel \
coding, > modulation, FFT,
> >> etc.), but
> >> > at this point I found that I was transmitting data with a \
very > high BER (for both
> >> links).
> >> > again, mentioning that there was no problem when sending on \
one > channel alone, I The
> >> USRP
> >> > Sink and Source settings are shown in the attached picture.
> >> > where
> >> > freq1=2.4G
> >> > freq2=2.39G
> >> > lo_off1=2M
> >> > lo_off2=-2M
> >> > samp_rate=300K
> >> > The two signals are separated using \
different frequencies, I > don't think there
> >> should
> >> > be any interference between them, and I have troubleshot \
errors > other than USRP
> >> source and
> >> > sink, so I think there is something wrong with my parameter
> settings, or I am using the
> >> > two RF channels in an incorrect way. How should I modify
> this?Looking forward to your
> >> > response£¡
> >> >
> >> > Best Regards!
> >> >
[Attachment #5 (text/html)]
<meta http-equiv="Content-Type" content="text/html; charset=GB18030"><div>Sorry I \
forgot to put the file</div><div style="position: \
relative;"><div><br></div><div><br></div><div style="font-size: 12px;font-family: \
Arial Narrow;padding:2px 0 2px \
0;">------------------ ÔʼÓʼþ ------------------</div><div \
style="font-size: 12px;background:#efefef;padding:8px;"><div><b>·¢¼þÈË:</b> \
"ÄÜÊéÄÜÑÔ" \
<2127629883@qq.com>;</div><div><b>·¢ËÍʱ¼ä:</b> 2022Äê12Ô 21ÈÕ(ÐÇÆÚÈý) Ï \
Îç5:18</div><div><b>ÊÕ¼þÈË:</b> "Marcus \
M¨¹ller"<mueller@kit.edu>;"discuss-gnuradio"<discuss-gnuradio@gnu.org>;<wbr></div><div></div><div><b>Ö÷Ìâ:</b> »Ø¸´£º \
»Ø¸´£º »Ø¸´£º Problems implementing USRP b210 dual channel \
transceiver</div></div><div><br></div><div>Hi,</div><div> I'm sorry that \
I was delayed last week. I conducted some experiments again (test_tx, test_rx in the \
attachment). I found that the two signals have been successfully separated under this \
setting and will not interfere with each other. Therefore, I believe that the cause \
of high bit error rate may be somewhere else. The other two GRCs in the attachment \
are what I want to achieve. I found this phenomenon:</div><div> I \
removed one of the "FEC extended decoders" on the receiving end (rx), and the other \
one performed very well. However, as long as the two "FEC extended decoders" modules \
existed at the same time, the bit error rate would become extremely high. I don't \
know what happened. I also didn't get a detailed explanation about this module from \
the official website.</div><div style="position: relative;"><div>Best \
Regards,</div><div>linge93</div><div><br></div><div style="font-size: \
12px;font-family: Arial Narrow;padding:2px 0 2px 0;">------------------ ÔʼÓʼþ \
------------------</div><div style="font-size: \
12px;background:#efefef;padding:8px;"><div><b>·¢¼þÈË:</b> \
"Marcus M¨¹ller" \
<mueller@kit.edu>;</div><div><b>·¢ËÍʱ¼ä:</b> 2022Äê12Ô 8ÈÕ(ÐÇÆÚËÄ) \
ÍíÉÏ6:23</div><div><b>ÊÕ¼þÈË:</b> "discuss-gnuradio"<discuss-gnuradio@gnu.org>;<wbr></div><div></div><div><b>Ö÷Ìâ:</b> Re: \
»Ø¸´£º »Ø¸´£º Problems implementing USRP b210 dual channel \
transceiver</div></div><div><br></div><br>On 12/7/22 13:49, ÄÜÊéÄÜÑÔ wrote:<br>> \
The number of data packets in ¢Ù is not correct, but the number of \
<br>> data packets in ¢Ú is correct. Therefore, to avoid more problems, I <br>> \
choose ¢Ú.<br>You were probably operating on a different frequency than you've \
thought!<br>> By viewing the pictures in the attachment and your explanation, f_ \
RF <br>> is LO frequency? Then the two channels share one LO, so setting f_ \
<br>> Offset adjusts the frequency to f_ target?<br>Exactly!<br>> \
I tried the following:<br>> freq1= \
2.4G<br>> freq2= 2.39G<br>> \
lo_off1= 5M<br>> \
lo_off2= -5M<br>> samp_rate=300K<br>> \
But the problem still exists, and the bit error rate is very high : \
(<br>well, there might be many reasons for that; one might be that the <br>sampling \
rate of 300 kHz is very low for the USRP, so filtering might be \
<br>suboptimal.<br>> Another thing I forgot to say is that I did a dual channel \
<br>> transmission experiment before (I call it experiment A. ), and the <br>> \
parameter settings are the same as when I first set them£¨freq1 = 2.4G, <br>> \
freq2=2.39G, lo_off1=2M, lo_off2=-2M,samp_rate=300k£©,which performs <br>> very \
well.<br><br>But you cannot have been operating on the frequencies you thought you \
<br>were using, so that success is a bit meaningless?<br><br>Best \
regards,<br><br>Marcus<br><br>> The only difference between experiment A and this \
experiment now is <br>> that the modulation of the signals on the RFA and RFB of \
experiment A <br>> are different. I copied the USRP sink and USRP source \
components <br>> directly from the GRC of experiment A, and the parameter settings \
are <br>> the same, experiment A performed very well, but in this experiment a \
<br>> high BER occurred, so now I am confused where the problem lies<br>> Best \
regards£¡<br>><br>><br>> ------------------ ÔʼÓʼþ \
------------------<br>> *·¢¼þÈË:* "Marcus M¨¹ller" \
<mmueller@gnuradio.org>;<br>> *·¢ËÍʱ¼ä:* 2022Äê12Ô 7ÈÕ(ÐÇÆÚÈý) Ï \
Îç5:37<br>> *ÊÕ¼þÈË:* "discuss-gnuradio"<discuss-gnuradio@gnu.org>;<br>> \
*Ö÷Ìâ:* Re: »Ø¸´£º Problems implementing USRP b210 dual channel <br>> \
transceiver<br>><br>> Sorry, typo, hit ctrl-enter to send accidentally when \
trying to fix <br>> it. Let me say it<br>> correctly:<br>><br>> Re: ¢Ù \
But you receive packets! So that's a good thing, I guess?<br>><br>> Re: ¢Ú So, \
maybe the attached figure helps. The offset is the <br>> difference between \
the<br>> physical LO frequency f_{RF}, and the center frequency of what becomes \
<br>> your baseband.<br>><br>> So, I incorrectly said "the offsets need to \
add up to 10 MHz"; correct <br>> would be to say that<br>> freq1-offset1 = \
freq2-offset2.<br>> Now, since freq2 = freq1 - 10 MHz follows<br>> \
freq1-offset1 = freq1 - 10 MHz - offset2<br>> 10 MHz = offset1 - \
offset2<br>><br>> Note that offsets can be negative.<br>><br>> Best \
regards,<br>> Marcus<br>><br>> On 07.12.22 10:30, Marcus M¨¹ller \
wrote:<br>> > Your LO offset still don't add up to the difference between freq1 \
<br>> and freq2. What<br>> > frequency is the physical LO supposed to have? \
It cannot have <br>> frequency 2.4 GHz - 5 MHz<br>> > and 2.39 + 2 MHz at \
the same time. These are different numbers!<br>> ><br>> > Best \
regards,<br>> > Marcus<br>> ><br>> > On 07.12.22 09:09, ÄÜÊéÄÜÑÔ \
wrote:<br>> >> Hi,<br>> >> Thank you for your \
reply, based on your suggestion I have <br>> tried the following:<br>> >> \
¢ÙNo LO offset set (no uhd.tune_request)<br>> >> \
Ch0:Center Freq : freq1<br>> >> \
Ch1:Center Freq : freq2<br>> >> \
£¨freq1 = 2.4G, freq2=2.39G,samp_rate=300k£©<br>> \
>> ¢ÚSet LO Offset<br>> >> \
Ch0:Center Freq : uhd.tune_request(freq1,lo_off1)<br>> \
>> Ch1:Center Freq : \
uhd.tune_request(freq2,lo_off2)<br>> >> \
£¨freq1 = 2.4G, freq2=2.39G, lo_off1=5M, <br>> \
lo_off2=5M,samp_rate=300k£©<br>> >> or £¨freq1 = \
2.4G, freq2=2.396G, lo_off1=2M, <br>> lo_off2=2M,samp_rate=300k£©<br>> >> \
or £¨freq1 = 2.4G, freq2=2.396G, lo_off1=2M, <br>> \
lo_off2=-2M,samp_rate=300k£©<br>> >><br>> >> \
for ¢Ù£º<br>> >> In this case, the number of packets \
received is incorrect and <br>> the problem becomes<br>> >> more \
serious.<br>> >> for ¢Ú£º<br>> >> \
In this case the BER is still very high (I don't think it's my <br>> system \
because the<br>> >> transmit power is set to 1 (Normalized) and the BER is \
quite low <br>> when using one RF<br>> >> channel, but I still think I'm \
using the USRPB210's dual channel <br>> transmission mode<br>> >> \
incorrectly)<br>> >> Best Regards£¡<br>> >><br>> >> \
------------------ ÔʼÓʼþ ------------------<br>> >> *·¢¼þÈË:* "Marcus \
M¨¹ller" <marcus.mueller@ettus.com>;<br>> >> *·¢ËÍʱ¼ä:* 2022Äê12Ô \
6ÈÕ(ÐÇÆÚ¶þ) ÍíÉÏ8:49<br>> >> *ÊÕ¼þÈË:* \
"discuss-gnuradio"<discuss-gnuradio@gnu.org>;<br>> >> *Ö÷Ìâ:* Re: \
Problems implementing USRP b210 dual channel transceiver<br>> >><br>> \
>> There's only one physical TX LO; so either you just don't specify <br>> \
offsets, OR they must<br>> >> add up to the difference between the two \
target frequencies.<br>> >><br>> >> In your case, the difference is \
10 MHz, but your offsets don't add <br>> up to 10 MHz, and<br>> >> you're \
requesting something impossible.<br>> >><br>> >> Best \
regards,<br>> >> Marcus<br>> >> On 06.12.22 12:45, ÄÜÊéÄÜÑÔ \
wrote:<br>> >> > Hi,<br>> >> > \
I am using OFDM + USRPB210 for data transmission. I am <br>> using two \
USRPB210s, one<br>> >> being<br>> >> > used as a \
transmitter and the other as a receiver. When I use <br>> only one of the \
channels<br>> >> > (RFA or RFB) the data can be transmitted \
properly. I needed to <br>> transmit two different<br>> >> data<br>> \
>> > at the same time, so I used both the USRP RFA and RFB. the \
<br>> baseband processing part<br>> >> of the<br>> >> > \
link was the same for both channels (including channel coding, <br>> modulation, \
FFT,<br>> >> etc.), but<br>> >> > at this point I found \
that I was transmitting data with a very <br>> high BER (for both<br>> >> \
links).<br>> >> > again, mentioning that there was no problem when \
sending on one <br>> channel alone, I The<br>> >> USRP<br>> >> \
> Sink and Source settings are shown in the attached picture.<br>> \
>> > where<br>> >> > \
freq1=2.4G<br>> >> > \
freq2=2.39G<br>> >> > lo_off1=2M<br>> \
>> > lo_off2=-2M<br>> >> > \
samp_rate=300K<br>> >> > The two \
signals are separated using different frequencies, I <br>> don't think \
there<br>> >> should<br>> >> > be any interference between \
them, and I have troubleshot errors <br>> other than USRP<br>> >> source \
and<br>> >> > sink, so I think there is something wrong with my \
parameter <br>> settings, or I am using the<br>> >> > two RF \
channels in an incorrect way. How should I modify <br>> this?Looking forward to \
your<br>> >> > response£¡<br>> >> ><br>> \
>> > Best Regards!<br>> >> ><br></div></div>
["test_rx.pdf" (application/octet-stream)]
["test_tx.pdf" (application/octet-stream)]
["semantic_demo_tx_double.pdf" (application/octet-stream)]
["semantic_demo_rx_double.pdf" (application/octet-stream)]
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