Ilia replied to the topic 'Custom driver for unidimensional fluxes (radio/photons)' in the forum. yesterday

Yes! I also tried to build an optical intensity interferometer but got stuck on timing issues.
Please allow some time to add at least some receiver, initially I'd add radio receiver, mostly due to transfer bottlenecks and timing limitations. After some radio receiver photon detectors could be added.
Regarding this project, it's a common dream for interferometry passionates I think, Hanbury Brown had this dream probably, and others still too. I think that LibINDI is the right place where to start. Somebody should start a thread here where to discuss about this, and RTL-SDR receiver could be of much help here, since of their versatility and wide range. If nobody will propose a driver for these I'll do it.
There is already a project named OpenVLBA , we'd have to contact the author and propose him to bring that project INDI compliant.
Ilias

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Ilia replied to the topic 'Custom driver for unidimensional fluxes (radio/photons)' in the forum. 3 days ago

Hi Radek,
Why do you need such resolution? Anything like VLBI ;) ? In such case, when having the possibility to get a optical fibre link, you can reach good resolutions and stability looking at White Rabbit , which is open-source and open-hardware, but this needs very special hardware. Otherwise one can point to sub-microsecond using PTP, this could be a possible implementation but there should be many on the web: www.meinbergglobal.com/english/products/ptp-ieee-1588.htm
Ilias.

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Ilia replied to the topic 'Custom driver for unidimensional fluxes (radio/photons)' in the forum. 6 days ago

Hi Kaczorek,
Instead of reaching raster high-speed fluxes one could log timestamps of pulses, or timing differences between peaks of waves. I studied a way to achieve such timing resolutions, however. Possible solutions could be Hydrogen Masers (very expensive) or Rubidium Standards. These clock types are really performant, keep in mind that Rubidium standards are the atomic clocks that the GPSs are equipped with.
The problem is how to log the pulses or waves. Since photon pulses are random one could use a TDC to keep logging the delays between pulses with a resolution of some picoseconds. There are also FPGA implementations (and open codes) of such devices so one could build with a single chip the capture and log sections.
In radio interferometry one could simply mix the two feeds using a common mixer in an analogue way and plot only the amplitude of the resulting signal, managing delays using longer or shortening cables.
Ilias.

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Ilia replied to the topic 'Custom driver for unidimensional fluxes (radio/photons)' in the forum. 6 days ago

Hi Jasem, I think I'm ready.. err.. I'm about new to github.. how can I submit a PR to indi?

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Ilia replied to the topic 'Issues with indi_eqmod and custom MC' in the forum. 7 days ago

Hi Jean-Luc
I made some progress:
You were right, the interrupt routine was continuosly called by the timer, and it couldn't end its cycle, so I disabled interrupts into the isr, and re-enabled them at the end of the call.
It's now working! Tracking, gotos are doing what expected.
There is another problem now: when I try to abort, it starts StopWaitMotor and it can't end, my firmware is always telling that the motors are running. I should investigate about this.
By the way, thanks for your help, and if you have any other suggestion.. you're welcome!
Ilias

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Ilia replied to the topic 'Custom driver for unidimensional fluxes (radio/photons)' in the forum. 7 days ago

I'd like to add a library with some functionalities and math operations used in Astronomy, like signal processing operations:
-Fourier transforms.
-Wavelets.
-Autocorrelation.
-Convolution/Deconvolution.
-Here the guiding algorithm could find place.
-Notch/Band pass filters.
-Others.
I collected most of these function into a C# library called ADPASDK (not well documented), which is part of my software, but I'd be happy to port them to INDI.

Ilias.

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Ilia replied to the topic 'Custom driver for unidimensional fluxes (radio/photons)' in the forum. 1 week ago

Jasem, As far as you know, do you think these properties suffice?

-Bandwidth (Hz, number)
-Observed Frequency (Hz, number)
-Sample Frequency (Hz, number)
-Bits per Sample (8, 16, 32, Number)
-Capture Duration (Sec, Number)
-Capture (blob, captured data, length=CaptureDuration*SampleFrequency[*Bpp])
---
I personally would add these ones, since the receiver I'm about to buy reads very slowly (Radioastrolab RAL10):
-BufferSize/Heartbeat (Number, for framed input)
-Raw wave/Intensity (Switch - maybe unnecessary as it can be done in hardware)
-Spectrum1 (Blob)
-Small library for FFT, Graphs, imaging and statistics into:
-Render1 (Blob)

Let me know your opinion,
Ilias.

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Ilia replied to the topic 'Custom driver for unidimensional fluxes (radio/photons)' in the forum. 1 week ago

I quickly created a new class named Detectors. I modified commit 4e1d1584181245471912d4059f630f39f65863ba from git, I added a new driver interface and enlarged the size of get/setDriverInterface type to uint32_t.
Added also two files: indidetector.cpp and indidetector.h.
All is provvisory, I successfully compiled it, but it misses many things, still incomplete, but it is a start.

Ilias.

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Ilia replied to the topic 'Issues with indi_eqmod and custom MC' in the forum. 1 week ago

To be honest I don't know if there's no reading. I don't think so however. Maybe it's a timing issue. Could a separate thread for reading from the MC help?

Ilias.

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Ilia replied to the topic 'Issues with indi_eqmod and custom MC' in the forum. 1 week ago

I solved by now by commenting out any read_eqmod after all SetXXX commands. It can now track and goto. I found some other bugs in my firmware but at least I can continue developing.

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Ilia replied to the topic 'Custom driver for unidimensional fluxes (radio/photons)' in the forum. 1 week ago

I'll do happily this work, please allow some day because I'm full of work in this moment.
I'll add the minimum required in a base class for monodimensional detectors (like Detectors class), then some sub-class could be "Analog Detectors" and "Pulse Detectors" (general, because one could use PMTs or APDs, or else Radio receivers).

If any other type of these kind of devices comes in your mind, you're welcome to contribute :D
Ilias.

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Ilia replied to the topic 'Issues with indi_eqmod and custom MC' in the forum. 1 week ago

Hi Jean-Luc, and thanks for the response.
I will try to do like you said (setting the minimum at command reception), but if you see into SetMicrostep() (called after a StartMotion) the step period is set to a minimum of 30. Also gotos are not limited in speed and this applies in both motion mode cases. When I issue a goto from the SynScan, speed is set automatically at maximum, and I got no problem.
I tried also to check if there is any issue with signed types in my code, with no luck.

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