07-28-2008 12:22 PM - last edited on 08-01-2008 02:57 PM by Support
08-01-2008 05:43 PM
03-24-2009 11:41 AM
04-06-2009 09:05 AM
You can find the filter spec mentioned in the soecification doc that comes along with the installer.
The IQ Fractional Resampler has an issue with handling the "ready for output" signal and hence you might be getting bad signals. This is being fixed and will be on NI-labs very soon.
See screenshot to make changes on your own to make it work.
Create a copy of the following VI and rename it to a suitable name
..\vi.lib\addons\_RF Fixed Point\M-PSK Demodulators\common\niFPGARFv2 Demodulator FIFO U32.vi
Add this VI to the IQ Fractional Resampler code and connect the terminals as shown in the screenshot.
06-19-2009 12:04 AM
I don't know much about Reed Solomon, but it looks like the function you have wouldn't work for CCSDS packets. Do you have plans to provide Reed Solomon decoders/encoders for CCSDS or maybe a VI that can do generic Reed Solomon? CCSDS is the standard for satellite telemetry used by most non-military satellites. Having CCSDS Reed Solomon support would allow us to get rid of some very overpriced boxes.
06-19-2009 12:46 AM
Yes, you are right that the RS encoder/decoder in the library is not generic. We would definitely look into developing CCSDS specific code. May I know what hardware are you using or planning to use as target?
06-19-2009 02:07 PM
We don't have hardware right now. We're still in the info gathering stage. I can tell you it would most likely be one of the Virtex-5 cRIO chassis.The complete system would have to do the following:
Viterbi decoding, convolution encoding
Frame Sync (with ability to detect signal inversion)
We have a site license for a FIPS certified AES IP core, Frame Sync & NRZ is something we could do ourselves if VIs don't exist. Convolution encoding isn't that difficult. Your Viterbi looks like it would work. It is the R-S that worries me. We could buy an IP core to do the work, but this project is price sensitive.
11-03-2009 03:53 AM
I am also thinking of using Reed Solomon decoder for CCSDS. Can I modify the code to make it work for CCSDS? Can you please provide some detail information of the working of current decoder?
11-19-2009 11:04 PM
CCDS seems to have more than one Reed Solomon configuration. Can you let me know which configuration do you want to implement?
Changing it manually might be huge task. The following material will be helpful if you want to try building the code on your own
Hope this helps
11-20-2009 09:50 PM
Thanks for your reply. I know it would be difficult to modify the existing IP for every configuration. What about just making it work on different field generator polynomial?
I was looking at the code and i could not understand the implementation of Galois field multipliers. Can you please tell what method is being used here?