Re: [Discuss-gnuradio] E312 receiver gets stuck
I used Ettus USRP B210.
I had this issue, no matter what modulation schemes I was implementing.
What I noticed was the fact that if the signal power drops below a value, the
whole receiver stopped and even the constellation was not updating.
I think the receiver block diagrams couldn’t recover after a signal drop.
Sent from Mail for Windows 10
From: Niloofar Toorchi
Sent: 19 February 2018 15:39
To: mansourabadi.mojt...@gmail.com
Cc: discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] E312 receiver gets stuck
Thank you Mansour, Which USRP did you use? E312? I know some one who used
flowgraph in E310 but did not face any problem. I do not know whether this is
related to USRP version or is a software issue.
Best,
Niloofar
On Mon, Feb 19, 2018 at 8:05 AM, wrote:
I had the same problem. Even when I built the flowgraph the problem remained.
I think it’s coming from the stages related to signal clock/phase/frequency
recovery. Most of these blocks are working as a state machine. For any reason,
when the received signal power drops, they probably go to an unknown state.
Unfortunately these blocks have no reset input to initialise them so what you
have to do is to re-run the program.
There might be a solution if you use code. But I haven’t used coding.
Sincerely,
Mansour.
On 18 Feb 2018, at 20:49, Niloofar Toorchi wrote:
Hi All,
I am using USRP E312. I used the available examples by Gnuradio,
benchmark_{rx,tx}.py to have a simple communication between transmitter and
receiver. I noticed that when the transmitter pauses sending, the receiver
freezes somehow and when the transmitter resumes packet transmission, the
receiver cannot receive anymore. Has any one experienced the same problem? Do
you think building flowgarph can solve this issue?
Thanks for your help,
Niloofar
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Re: [Discuss-gnuradio] Fwd: USRP Packet Decoder and Encoder
If you have access to the examples available in GNURadio package, please check: \examples\digital\packet Or \example\digital\demod The parameters are straight forward though. Samples Per Symbol for your case is 2. Filter Rollof Factor of 0.35 is fine. Prototype Filter Size of 44 or 45 does the job. Loop Bandwidth is the famous constant of 2*pi/100. I use these values and the flowgraph seems to be fine. I hope they do the same for you. Cheers. Sent from Mail for Windows 10 From: Brian Sent: 04 July 2017 19:12 To: Mojtaba Mansour Abadi Subject: RE: [Discuss-gnuradio] Fwd: USRP Packet Decoder and Encoder Thanks How do I configure the fll band edge From: Mojtaba Mansour Abadi Sent: 04/07/2017 18:53 To: discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] Fwd: USRP Packet Decoder and Encoder Hi Brian, Good work you attached the flowgraphs. My suggestion is to either 1- add an FLL Band-Edge block before the Polyphase Clock Recovery block at Rx; so your Rx side looks like this: USRP Source -> FLL Band-Edge -> Polyphase Clock Recovery -> CMA Equalizer -> ... Or 2- Instead of low level blocks for modulation and demodulation, use PSK Mod and PSK Demod from GNURadio. So the Tx looks like: File Source -> Packet Encoder -> PSK Mod -> USRP Sink And RX looks like: USRP Source -> PSK Demod -> Repack Bits -> Packed to Unpacked -> Packed Decoder -> File Sink Of course PSK Mod/Demod are deprecated but I found them to be quite robust and functional. I hope it helps. Cheers. Sent from Mail for Windows 10 From: Brian Clark Sent: 04 July 2017 18:34 To: discuss-gnuradio@gnu.org Subject: [Discuss-gnuradio] Fwd: USRP Packet Decoder and Encoder Hi All, I have gone through my flow graph and can confirm that with no USRPs connected I can successfully transmit a file which includes encoding and QPSK modulation at the transmitter, and the reverse at the receiver. The attached flow graph is my file. Moving on and using my successful flow graph I have now split this and introduces USRP radios. This is the second flowgraph, you will notice that I have disabled the transmitter side (the opposite is true on my other file on my transmitting usrp) The results I have monitored include; 1. A file is created with 0B - even before the transmitter is turned on 2. The QT GUI Sink on the receiver appears to raise the noise floor to -40db (quite wide and not limited to the band). The transmitter shows a fairly well defined signal 3. At no point does there appear to be an output from the Demodulator My Thoughts are now that the blocks are working, but there is a problem with the transmission of the signal over USRP. I have tested both USRP as a sinmple FM RXer and FM Txer successfully. Could this be a syncronisation problem? or a saturation one? This would lead to signal being received and the access code not present therefore no output present -- Forwarded message -- From: Brian Date: 4 July 2017 at 10:38 Subject: RE: [Discuss-gnuradio] USRP Packet Decoder and Encoder To: Mojtaba Mansour Abadi Derek and Mojitaba, Thanks for your comments. I am not in front of my machines at the moment but I did attempt a single flow graph without usrp and that worked well. My usrp are connected via antenna and the rxer threshold is -120db with just noise and -40db with a signal. I will try your suggestions and let you know if unsuccesful I will upload the grc files. Thanks Brian From: Mojtaba Mansour Abadi Sent: 04/07/2017 10:15 To: discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] USRP Packet Decoder and Encoder Hi Brian, >From my experience, if packet decoder is not receiving any detectable preamble >bit sequence there will be no output. >From your email I realised that you’re receiving noise-like signal if decoder >is bypassed. So I also agree with Derek that either you probably are not >receiving any signal or the modulation/demodulation procedure is not performed >correctly. Try your system back-to-back without any packetisation mechanism. Use a very short length vector source with couple of numbers as data. Make sure you are receiving the same sequence at the Rx side. If you don’t. Try a loopback system without any USRPs and see if your data is received at the Rx side. Cheers. Sent from Mail for Windows 10 From: Derek Kozel Sent: 04 July 2017 08:48 To: Brian Cc: GNURadio Discussion List Subject: Re: [Discuss-gnuradio] USRP Packet Decoder and Encoder Hello Brian, It will be difficult to provide useful advice without seeing your flowgraph. Does your file correctly get written if you bypass the actual radios and simply connect the transmitter and receiver flowgraphs together? If it does then you probably need to add synchronization to your receiver. Another good check is to look at the received raw spectrum and ensure that the signal is being received
Re: [Discuss-gnuradio] Fwd: USRP Packet Decoder and Encoder
Hi Brian, Good work you attached the flowgraphs. My suggestion is to either 1- add an FLL Band-Edge block before the Polyphase Clock Recovery block at Rx; so your Rx side looks like this: USRP Source -> FLL Band-Edge -> Polyphase Clock Recovery -> CMA Equalizer -> ... Or 2- Instead of low level blocks for modulation and demodulation, use PSK Mod and PSK Demod from GNURadio. So the Tx looks like: File Source -> Packet Encoder -> PSK Mod -> USRP Sink And RX looks like: USRP Source -> PSK Demod -> Repack Bits -> Packed to Unpacked -> Packed Decoder -> File Sink Of course PSK Mod/Demod are deprecated but I found them to be quite robust and functional. I hope it helps. Cheers. Sent from Mail for Windows 10 From: Brian Clark Sent: 04 July 2017 18:34 To: discuss-gnuradio@gnu.org Subject: [Discuss-gnuradio] Fwd: USRP Packet Decoder and Encoder Hi All, I have gone through my flow graph and can confirm that with no USRPs connected I can successfully transmit a file which includes encoding and QPSK modulation at the transmitter, and the reverse at the receiver. The attached flow graph is my file. Moving on and using my successful flow graph I have now split this and introduces USRP radios. This is the second flowgraph, you will notice that I have disabled the transmitter side (the opposite is true on my other file on my transmitting usrp) The results I have monitored include; 1. A file is created with 0B - even before the transmitter is turned on 2. The QT GUI Sink on the receiver appears to raise the noise floor to -40db (quite wide and not limited to the band). The transmitter shows a fairly well defined signal 3. At no point does there appear to be an output from the Demodulator My Thoughts are now that the blocks are working, but there is a problem with the transmission of the signal over USRP. I have tested both USRP as a sinmple FM RXer and FM Txer successfully. Could this be a syncronisation problem? or a saturation one? This would lead to signal being received and the access code not present therefore no output present -- Forwarded message -- From: Brian Date: 4 July 2017 at 10:38 Subject: RE: [Discuss-gnuradio] USRP Packet Decoder and Encoder To: Mojtaba Mansour Abadi Derek and Mojitaba, Thanks for your comments. I am not in front of my machines at the moment but I did attempt a single flow graph without usrp and that worked well. My usrp are connected via antenna and the rxer threshold is -120db with just noise and -40db with a signal. I will try your suggestions and let you know if unsuccesful I will upload the grc files. Thanks Brian From: Mojtaba Mansour Abadi Sent: 04/07/2017 10:15 To: discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] USRP Packet Decoder and Encoder Hi Brian, >From my experience, if packet decoder is not receiving any detectable preamble >bit sequence there will be no output. >From your email I realised that you’re receiving noise-like signal if decoder >is bypassed. So I also agree with Derek that either you probably are not >receiving any signal or the modulation/demodulation procedure is not performed >correctly. Try your system back-to-back without any packetisation mechanism. Use a very short length vector source with couple of numbers as data. Make sure you are receiving the same sequence at the Rx side. If you don’t. Try a loopback system without any USRPs and see if your data is received at the Rx side. Cheers. Sent from Mail for Windows 10 From: Derek Kozel Sent: 04 July 2017 08:48 To: Brian Cc: GNURadio Discussion List Subject: Re: [Discuss-gnuradio] USRP Packet Decoder and Encoder Hello Brian, It will be difficult to provide useful advice without seeing your flowgraph. Does your file correctly get written if you bypass the actual radios and simply connect the transmitter and receiver flowgraphs together? If it does then you probably need to add synchronization to your receiver. Another good check is to look at the received raw spectrum and ensure that the signal is being received at an appropriate power level. How do you have the two USRPs connected? Antennas or coax with an attenuator? Regards, Derek On Mon, Jul 3, 2017 at 11:29 PM, Brian wrote: I have a flow graph that currently has a packet encoder at the transmitter and an encoder at the receiver. I am attempting to send a file from one usrp to the other. On investigating the output of the receiver it would not appear that it is processing anything possibly because of the access code but I have conformed they match and are suitably long and random. The file I get out is 0bytes. If I bypass the decoder a large file is created, although large and unusable (noise) Any advice on how to proceed will be gratefully received and a pre-configured tx and rx flow graph will be most welcome. ___
Re: [Discuss-gnuradio] USRP Packet Decoder and Encoder
Hi Brian, >From my experience, if packet decoder is not receiving any detectable preamble >bit sequence there will be no output. >From your email I realised that you’re receiving noise-like signal if decoder >is bypassed. So I also agree with Derek that either you probably are not >receiving any signal or the modulation/demodulation procedure is not performed >correctly. Try your system back-to-back without any packetisation mechanism. Use a very short length vector source with couple of numbers as data. Make sure you are receiving the same sequence at the Rx side. If you don’t. Try a loopback system without any USRPs and see if your data is received at the Rx side. Cheers. Sent from Mail for Windows 10 From: Derek Kozel Sent: 04 July 2017 08:48 To: Brian Cc: GNURadio Discussion List Subject: Re: [Discuss-gnuradio] USRP Packet Decoder and Encoder Hello Brian, It will be difficult to provide useful advice without seeing your flowgraph. Does your file correctly get written if you bypass the actual radios and simply connect the transmitter and receiver flowgraphs together? If it does then you probably need to add synchronization to your receiver. Another good check is to look at the received raw spectrum and ensure that the signal is being received at an appropriate power level. How do you have the two USRPs connected? Antennas or coax with an attenuator? Regards, Derek On Mon, Jul 3, 2017 at 11:29 PM, Brian wrote: I have a flow graph that currently has a packet encoder at the transmitter and an encoder at the receiver. I am attempting to send a file from one usrp to the other. On investigating the output of the receiver it would not appear that it is processing anything possibly because of the access code but I have conformed they match and are suitably long and random. The file I get out is 0bytes. If I bypass the decoder a large file is created, although large and unusable (noise) Any advice on how to proceed will be gratefully received and a pre-configured tx and rx flow graph will be most welcome. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] TUN/TAP PDU not working
Hi, These are the output of the commands: PC1: enp0s31f6 Link encap:Ethernet HWaddr f4:8e:38:b3:42:db UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:19 Memory:f7e8-f7ea enp5s0Link encap:Ethernet HWaddr 00:0a:f7:93:1a:93 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:18 loLink encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:8305 errors:0 dropped:0 overruns:0 frame:0 TX packets:8305 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1 RX bytes:617488 (617.4 KB) TX bytes:617488 (617.4 KB) tap0 Link encap:Ethernet HWaddr 02:89:56:03:96:e1 inet addr:192.168.200.1 Bcast:192.168.200.255 Mask:255.255.255.0 inet6 addr: fe80::89:56ff:fe03:96e1/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:10 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:732 (732.0 B) PC2: enp0s31f6 Link encap:Ethernet HWaddr d4:81:d7:9b:de:e5 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:16 Memory:ef30-ef32 loLink encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:1428 errors:0 dropped:0 overruns:0 frame:0 TX packets:1428 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1 RX bytes:108539 (108.5 KB) TX bytes:108539 (108.5 KB) tap0 Link encap:Ethernet HWaddr 86:2f:2a:03:4c:35 inet addr:192.168.200.10 Bcast:192.168.200.255 Mask:255.255.255.0 inet6 addr: fe80::842f:2aff:fe03:4c35/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:10 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:732 (732.0 B) wlp2s0Link encap:Ethernet HWaddr 14:ab:c5:3c:96:73 inet6 addr: fe80::2c1a:98d8:1f9f:9d23/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:618 errors:0 dropped:0 overruns:0 frame:0 TX packets:128 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:75975 (75.9 KB) TX bytes:14759 (14.7 KB) I also noticed something odd. When I run the flowgraph on the machines. Tx and Rx LEDs are one on both USRPS. However as soon as I assign an IP Address to the virtual eth cards, the Rx LED on one of the USRPs goes off. It happens randomly so sometimes it is PC1 side and sometimes PC2. Cheers. On 14 June 2017 at 23:05, Cinaed Simson wrote: > On 06/14/2017 12:15 AM, mansourabadi.mojt...@gmail.com wrote: > > I don't know exactly what you mean by bringing up interfaces. > > > > Let's say I assign 192.168.200.1 to PC1. > > For sure I can ping 192.168.200.1 on PC1. > > But from PC2, this destination is unreachable. > > > > I don't know what the issue could be. Since. I'm just a Linux user (not > an expert) I have no clue where the problem is. > > I'm going to assume the B210 isn't using the IP address > > 192.168.200.1 > > Can you ping the B210 from PC1? > > The B210 should be using the IP address > > 192.168.200.2 > > Unless you create a virtual Ethernet device on PC2 you'll never be able > to ping the PC1 or the B210 from PC2. > > Also, post the outputs of > > ifconfig > > for PC1 and PC2. > > Also, I don't know anything about the B210 - it may not be possible to > do what you're trying to do - but try it anyway. > > -- Cinaed > > > > > > > Cheers. > > > > Sincerely, > > Mansour. > > > >> On 14 Jun 2017, at 00:39, Cinaed Simson > wrote: > >> > >>> On 06/13/2017 12:41 PM, Mojtaba Mansour Abadi wrote: > >
Re: [Discuss-gnuradio] TUN/TAP PDU not working
I think I found out the possible source of problem. Toda I found out the following issues with “Packet Encoder/Decoder” blocks. I replaced the TUNTAP PDU block with a Wav File Source and Audio Sink blocks at the transmitter and receiver, respectively. I noticed that always the receiver side must be executed after the transmitter side. Otherwise I cannot hear any audio. Now I wonder how I can solve this problem. BTW, I also tried to use the gnuradio tunnel.py example in /example/digital/narrowband; But it won’t work and it always give an error. The other tunnel.py example in /examples/digital/ofdm, however, works fine. But still I cannot ping the machines. Cheers. Regards, Mansour. https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 Mojtaba Mansour Abadi Editorial Board Journal of Advanced Engineering IGRPS http://igrps.org/journal-of-advanced-engineering.php From: Cinaed Simson Sent: 14 June 2017 00:39 To: discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] TUN/TAP PDU not working On 06/13/2017 12:41 PM, Mojtaba Mansour Abadi wrote: > Hi Everyone, > > > > I am trying to connect two PCs using B210 USRPs and tunnelling method. > > > > After going through examples and documents I came ups with the attached > flowgraph. > > > > I run the flowgraph on both machines and once the virtual Ethernet card > is created I use “ifconfig” command to assign an IP address to it. > > > > However the machines cannot ping each other. Did you bring up the interfaces? Are the IP addresses of the tuntaps reachable with a ping from your PC? -- Cinaed > > > > I use USB GNURadioLiveDVD > <https://wiki.gnuradio.org/index.php/GNURadioLiveDVD> as the OS. > > > > I wonder which part is not right. The flowgraph is also attached to the > email. > > > > > > Regards, > Mansour. > > https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 > > Mojtaba Mansour Abadi > Editorial Board > Journal of Advanced Engineering > IGRPS > > http://igrps.org/journal-of-advanced-engineering.php > > > > > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Streaming Live Video
Hi Everyone, Is it possible to stream a live video in GNURadio? What I want to do is to transmit the video over air (using a pair of USRP) for demonstration purposes. Even if the video is from a file, it would be perfect. Cheers. -- Regards, Mansour. https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Correlation Estimator Block
Hi Cinaed, Thanks a lot for the complete reply. I appreciate it. I will implement your suggestions and see what the output will be and let you know. Cheers. On 25 May 2017 at 09:56, Cinaed Simson wrote: > Suppose someone asked you to implement your flow graph on a transmitter > and receiver separated by an air gap. > > Where would you tap into the signal with the Correlation Estimator? > > I would tap into the signal at the end of the receiver - at the virtual > source with the decoded signal - or the very end of the flow chart. > > And you've already demonstrated the output of the flow graph is the same > as input, i.e., you can reliably transit and receive a BPSK signal. > > Instead of trying to cram all these block into 1 flow graph, there's an > easier way. > > Replace the entire flow graph with a Channel Model. Use a complex vector > equal to the sum of the data and preamble. Feed the complex vector into > a complex Stream to Tagged Stream block and then feed the tagged stream > into the Channel Model. Place the Correlation Estimator on the other > side of the Channel Model and you have something that begins to look like > > /share/gnuradio/examples/digital/pack > /example_corr_est.grc > > Use your Constellation Object to configure the Modulate Vector for BPSK. > > And after you've work out all the details of the Correlation Estimator, > you can graph it back onto the original flow graph. > > -- Cinaed > > > On 05/24/2017 10:32 AM, Mojtaba Mansour Abadi wrote: > > Hi Everyone, > > > > > > I am trying to benefit "Correlation Estimator" block to tag the preamble > > of the transmit bit sequence in a QPSK-based system > > > > > > The modulation is done as: > > Data + Preamble -> Constellation Modulator > > > > > > The way I am doing the demodulation is: > > AGC -> FLL Band-Edge -> Correlation Estimator -> Correlation Estimator > > -> Polyphase Clock Sync -> CMA Equaliser -> Costas Loop > > > > The hard decoding is done as: > > Constellation Decoder -> Differential Decoder -> Map -> Unpacked to > Packed > > > > After I execute the flowgraph, for a few seconds everything works fine > > and I receive the correct sequences. However, after a while, the > > received bits are not correct and their pattern changes periodically. > > > > When I bypass the "Correlation Estimator" block, everything works fine > > and I receive the correct data. > > > > I am confused. Is the correlation block suppose to deteriorate the > > demodulation performance? > > > > The flowgraph is attached to the email. > > > > > > -- > > Regards, > > Mansour. > > > > https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 > > > > > > ___________ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -- Regards, Mansour. https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Correlation Estimator Block
Hi Everyone, I am trying to benefit "Correlation Estimator" block to tag the preamble of the transmit bit sequence in a QPSK-based system The modulation is done as: Data + Preamble -> Constellation Modulator The way I am doing the demodulation is: AGC -> FLL Band-Edge -> Correlation Estimator -> Correlation Estimator -> Polyphase Clock Sync -> CMA Equaliser -> Costas Loop The hard decoding is done as: Constellation Decoder -> Differential Decoder -> Map -> Unpacked to Packed After I execute the flowgraph, for a few seconds everything works fine and I receive the correct sequences. However, after a while, the received bits are not correct and their pattern changes periodically. When I bypass the "Correlation Estimator" block, everything works fine and I receive the correct data. I am confused. Is the correlation block suppose to deteriorate the demodulation performance? The flowgraph is attached to the email. -- Regards, Mansour. https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 PSK_Mod_Demod.grc Description: Binary data ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] qt_gui not found
Hi Ali, First of all, based on the documentations provided by GNURadio, it's better to use QT GUIs rather than Wx GUIs. It looks like in the upcoming versions, the are going to put Wx GUIs aside. Anyway, if you are using GNURadio Companion, just double click on "Options" block which is by default on the top left corner of your canvas. In the popped up window, select the graphical interface you want by changing the "Generate Options" parameter. Note that in a single file you only can use either QT or Wx. You cannot use them both together. I hope it helps. On 22 May 2017 at 11:50, Ali Khanjani wrote: > hi there, When i want to use wx gui scope i encounter to the error that > qt_gui not found so what should i do i this case? > please help me > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- Regards, Mansour. https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] PSK/QAM Demodulation Issue
Thanks a lot Cinaed for the tips, in particular, the symmetry order and CMA equaliser. I did what you suggested about sps variable. However, it didn't help. Besides as far as I know form GNURadio documentation, samples/symbol is referring to the samples representing a single constellation symbol so increasing this parameter is equivalent to interpolating the signal. It doesn't have to do anything with the modulation scheme. Please correct me if I am wrong. Cheers, Mansour. On 17 May 2017 at 21:43, Cinaed Simson wrote: > m-psk for m=2, has 2 samples/symbol and log2(m)=1 - or 1 bit per symbol. > > Also, the polyphase clock has an input of 4 samples and output of 1 sps. > It should have input of 2 sps and output of 1 sps. > > Just change the sps everywhere to 2. > > Also, note there are only 2 symbols in the symbol map of the > Constellation object so for sps equal to 2 the symmetry is 2 - or there > will be 2 clusters on a horizontal straight line. > > Except when you use a tap in the Channel Model of 1+1j which will > probably rotate the line by 45 degrees to the horizontal. > > In any case, this is known as bpsk - or your case dbpsk - differential > bpsk. > > I would add the CMA Equalizer between the Polyphase clock and Costa Loop. > > -- Cinaed > > > > On 05/17/2017 08:59 AM, Mojtaba Mansour Abadi wrote: > > Hi Everyone, > > > > The flowgraph I am implementing is simple and straight forward. I am > > modulating a set of data plus preamble. The modulations I am looking at > > are either PSK or QAM. After a block of "Channel Model" in the > > flowgraph, I want to demodulate the signal and obviously, for fair SNR > > values I should receive the same preamble and data values. > > > > Now the problem is that when I use the deprecated "PSK/QAM Mod" and > > "PSK/QAM Demod", everything works fine. However, based on the examples > > in "/digital/demod" and "/digital/packet" shiped with > > gnuradio companion, when I try to use the "FLL Band-Edge" followed by > > "Correlation Estimator", "Polyphase Clock Sync", and "Costas Loop" to > > compensate the channel for PSK modulation, the results I am getting are > > not correct (see the attached picture and file). > > > > It would be your kind if you could answer my questions please: > > > > 1- What is the correct way of demodulating the received signal? > > 2- In the provided examples, no equalizer is used after "Polyphase Clock > > Sync", whereas in a tutorial available at Gnuradio website a "CMA > > Equaliser" is needed there. So which one is the correct one? > > 3- If I move to QAM modulation, the only thing I need to do would be > > replacing "Costas Loop" with a "Constellation Receiver", right? > > > > Cheers. > > > > Regards, > > Mansour. > > > > https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 > > > > > > ___ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -- Regards, Mansour. https://www.linkedin.com/in/mojtaba-mansour-abadi-4311b451 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Performing the required compensation steps for PSK/QAM modulations at the receiver
Hi Everyone, The flowgraph I am implementing is simple and straight forward. I am modulation a set of data and a known preamble. The modulations I am looking at are either PSK or QAM. After a block of "Channel Model", I want to demodulate the signal and obviously, for fair SNR values I should receive the same preamble and data values. Now the problem is that when I use the deprecated "PSK/QAM Mod" and "PSK/QAM Demod", everything works fine. However, based on the examples in "/digital/demod" and "/digital/packet", when I try to use the "FLL Band-Edge" followed by "Correlation Estimator", "Polyphase Clock Sync", and "Costas Loop" to compensate the channel for PSK modulation, the results I am getting are not correct. It would be your kind if you could answer my questions please: 1- What is the correct way of demodulating the received signal? 2- In the provided examples, no equalizer is used after "Polyphase Clock Sync", whereas in a tutorial available at Gnuradio website a "CMA Equaliser" is needed there. So which one is the correct one? 3- If I move to QAM modulation, the only thing I need to do would be replacing "Costas Loop" with a "Constellation Receiver", right? Cheers. PS: the flowgraph I am using is attached to this email. Test.grc Description: Binary data ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
