Re: Radio Astronomy Raspberry Pi image with GNU Radio 3.10.1
Great news On Friday, February 25, 2022, Glen Langston wrote: > Hello Aficionados, > > Franco Venturi has been busy cleaning up the Raspberry Pi Operating > system for use with Radio Astronomy. GnuRadio version 3.10.1.1 is > installed in the > Raspberry Pi operating system is now on the cutting edge. > > The Operating system is now 64bit, which is supposed to increase the > efficiency of the software. > > The installation guide and operating system are available for download > in this shared Google Drive: > > https://drive.google.com/drive/folders/1t2soWvGIgze7wg- > 7QGlVgB0m3Q-BR3C-?usp=sharing > > The document and OS are tagged with date 22Feb24. > The operating system is compressed to 2.26 Giga-Bytes: > NsfGR310-22Feb24.img.xz > The guide name is: > RadioAstronomyWithRaspberry-2022Feb24.pdf > > Hope this is helpful > > Glen > > This version is tested with these SDRs: > > AIRSPY R2, Mini, > SDRPLay RSP1A > RTL-SDR > PlutoSDR > > > -- Dr. Robert W McGwier, Ph.D. Adjunct Faculty, Virginia Tech ARDC Member of Board N4HY: ARRL, TAPR, AMSAT, EARC, CSVHFS Sky: AAVSO, SkyHub, Auburn AS, Skyscrapers
Radio Astronomy Raspberry Pi image with GNU Radio 3.10.1
Hello Aficionados, Franco Venturi has been busy cleaning up the Raspberry Pi Operating system for use with Radio Astronomy. GnuRadio version 3.10.1.1 is installed in the Raspberry Pi operating system is now on the cutting edge. The Operating system is now 64bit, which is supposed to increase the efficiency of the software. The installation guide and operating system are available for download in this shared Google Drive: https://drive.google.com/drive/folders/1t2soWvGIgze7wg-7QGlVgB0m3Q-BR3C-?usp=sharing The document and OS are tagged with date 22Feb24. The operating system is compressed to 2.26 Giga-Bytes: NsfGR310-22Feb24.img.xz The guide name is: RadioAstronomyWithRaspberry-2022Feb24.pdf Hope this is helpful Glen This version is tested with these SDRs: AIRSPY R2, Mini, SDRPLay RSP1A RTL-SDR PlutoSDR
Re: Add tags without copying samples?
Forgot to add: propagating tags from all inputs to the output is the default tag propagation policy, so B has to do essentially nothing if it doesn't itself care for the tags. On 25.02.22 21:55, Marcus Müller wrote: Hi Thomas, sadly, within the GNU Radio 3.x framework, this isn't possible. There's one possible "lower effort" solution. Assume you have this Source -> A -> B -> Sink where A is the block that currently needs to copy items just to add tags. We can now do Source --> B -> Sink \-> A -/^ where B is doing some functionality that you needed anyway. Now, B just gets a second input, that it completely ignores – except for the tags. A gets modified in that it doesn't copy the input, but simply says "hey, I produced items", without actually producing items; B would ignore them anyways. A, however, adds the tags. Not quite sure this helps you much... Best regards, Marcus On 25.02.22 17:36, Thomas Lorblanchès wrote: Hi all, I have some custom blocks that do not change the samples but only add tags in the output stream. At very high sampling rates, all these "memcpy" operations to copy the input samples to the output stream take a lot of time and put a lot of memory pressure on the system, and are completly useless on an algorithmic point of view. Is there a clever way to add tags without copying the samples? Thanks for your answers. Thomas
Re: Add tags without copying samples?
Hi Thomas, sadly, within the GNU Radio 3.x framework, this isn't possible. There's one possible "lower effort" solution. Assume you have this Source -> A -> B -> Sink where A is the block that currently needs to copy items just to add tags. We can now do Source --> B -> Sink \-> A -/^ where B is doing some functionality that you needed anyway. Now, B just gets a second input, that it completely ignores – except for the tags. A gets modified in that it doesn't copy the input, but simply says "hey, I produced items", without actually producing items; B would ignore them anyways. A, however, adds the tags. Not quite sure this helps you much... Best regards, Marcus On 25.02.22 17:36, Thomas Lorblanchès wrote: Hi all, I have some custom blocks that do not change the samples but only add tags in the output stream. At very high sampling rates, all these "memcpy" operations to copy the input samples to the output stream take a lot of time and put a lot of memory pressure on the system, and are completly useless on an algorithmic point of view. Is there a clever way to add tags without copying the samples? Thanks for your answers. Thomas
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Re: Sudden signal jumps
On 2022-02-25 11:26, Zentarra, Michael wrote: Hello everyone, I was experimenting with two USRPs and encountered something I could not explain. The setup is: HostA -> B210 -> Cable+Attenuator -> N310 -> HostB. GNURadio on the TX side is simply playing a signal via the signal source block into the UHD USRP Sink. On the RX side the USRP Source block is saving the signal through a head block into a file sink. The received signal seems to contain sudden, periodic jumps as can be seen in the picture below. For the attached picture the raw I and Q signal is plotted. The jumps happen at different tested sample rates, frequencies and gains on both sides. In the depicted example the signal source block sent a constant with amplitude one. Center frequency was set to 2,48 GHz with sample rates on both sides at 25,6 MHz. One can see the center frequency offset as expected but the signal is sometimes jumping in 2 adjacent samples which indicates to me that the receiver is adjusting something. This effect can also be seen at other sent waveforms. Does somebody know what causes such a behavior? Thank you in advance! Kind regards Michael Try backing off the baseband amplitude a little bit. Also, if you're sending a constant, that may cause the DC removal to "kick in". Are you getting any "U" on the TX side or "O" on the RX side?
Sudden signal jumps
Hello everyone, I was experimenting with two USRPs and encountered something I could not explain. The setup is: HostA -> B210 -> Cable+Attenuator -> N310 -> HostB. GNURadio on the TX side is simply playing a signal via the signal source block into the UHD USRP Sink. On the RX side the USRP Source block is saving the signal through a head block into a file sink. The received signal seems to contain sudden, periodic jumps as can be seen in the picture below. For the attached picture the raw I and Q signal is plotted. The jumps happen at different tested sample rates, frequencies and gains on both sides. In the depicted example the signal source block sent a constant with amplitude one. Center frequency was set to 2,48 GHz with sample rates on both sides at 25,6 MHz. One can see the center frequency offset as expected but the signal is sometimes jumping in 2 adjacent samples which indicates to me that the receiver is adjusting something. This effect can also be seen at other sent waveforms. Does somebody know what causes such a behavior? Thank you in advance! [cid:image001.png@01D82A67.B01872E0] Kind regards Michael
Add tags without copying samples?
Hi all, I have some custom blocks that do not change the samples but only add tags in the output stream. At very high sampling rates, all these "memcpy" operations to copy the input samples to the output stream take a lot of time and put a lot of memory pressure on the system, and are completly useless on an algorithmic point of view. Is there a clever way to add tags without copying the samples? Thanks for your answers. Thomas
