Looking for linux real-time DSP

[ON4CKM]

Hello,

I would like to connect the audio output of my receiver (IC706MKII) to the PC and then have some software do processing on the audio to improve the reception of weak signals (band filter, notch filter, etc). I run all my computers on Linux. Programs I find seem to be all for Windows.

Looking for people who want to share their experience. What software did you use? What are the results like?

My main goal is to improve RX audio. TX audio processing is not needed now but may be nice for the future.

Cedric

[KB4MB]

There are some programs in wine that would work, maybe...  however I have two sound cards and find that support terrible in WINE, so I am out of luck.  There is one made by an Italian ham, and one by a Japanese ham that I remember were pretty good:
http://www.dxzone.com/catalog/Software/DSP/

What you need to do is use a VST plugin.  This support in linux is shaky as well - but this will start steering you:
http://www.linuxjournal.com/node/1000192

[M0HCN]

Linrad or possibly the Gnuradio project are both really SDR setups but could possibly be made to do what you want.

Other then that maybe some processing chain using jack-rack and possibly jamin?

Regards, Dan.

[K4FMH]

This isn't a full blown version of what you want....but have you tried Audacity? It has some tools to remove hiss, etc., from line-in inputs such as from a receiver.

Frank
K4FMH

[W0BTU]

Linrad. The best there is.
http://www.sm5bsz.com/linuxdsp/linrad.htm
http://groups.google.com/group/linrad

[KB4MB]

I wasn't sure if Linrad would do what you need - but I think it will.  Remember though, it will only work on the audio, it will do nothing for your IF stages, so if you are swamped by signals there, no amount of AF filtering will be 100% effective. 

However, if you circumstances allow you to operate with your computer, you will certainly save money compared to an outboard processor...

[W0BTU]

  Remember though, it will only work on the audio, it will do nothing for your IF stages, so if you are swamped by signals there, no amount of AF filtering will be 100% effective. 

True. But that's what narrower (than SSB) filters are for. Not that filters are cure-alls (too-narrow filters can introduce distortion that reduces the effectiveness of DSP software), but I think they are under-utilized.

The problem I have with Linrad is the utter lack of documentation. I have it installed, but every time I go to use it, I quickly lose interest.