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cjcliffe / CubicSDR

Cross-Platform Software-Defined Radio Application
http://www.cubicsdr.com
GNU General Public License v2.0
2.05k stars 252 forks source link

Real need for specific liquid-dsp calls for Windows ? #537

Closed vsonnier closed 7 years ago

vsonnier commented 7 years ago

@cjcliffe Hello ! I have a question about existing Windows specific liquid-dsp code. Indeed when looking up for #ifdef WIN32 blocks of code, I fall upon a specific liquid-dsp code made for Windows in ModemLSB and ModemUSB. The origin of this specific code is commit 305cd4bf, saying "Temporary FIR fix for windows"

Do you remember in what consists this fix, and if it is still valid today, now that we have liquid-dsp v1.30 also on Windows? When I experimented on Windows by enabling the same iirfilt_crcf_create_lowpass call as the others, neither LSB / USB crash, but I don't have LSB/USB stations around so couldn't test it really worked or not as expected.

This is merely a matter of removing platform-specific code whenever we can.

cjcliffe commented 7 years ago

@vsonnier if liquid-dsp is up to date then there's no need for the windows-specific fix.

The built-in SSB modems don't suppress the side bands well and have a tendency to drift like they're tracking a carrier regardless of the carrier setting; works brilliantly for AM /w carrier though.

As a result I did my own LSB/USB implementation which works much better but the equivalent functions weren't available or behaved differently on windows -- So I found another combination that did almost as well but is likely far less efficient and could easily be dropped now that liquid-dsp is ready.

vsonnier commented 7 years ago

@cjcliffe Thanks for the explanation. Do you want to confirm by testing yourself if it is OK now for Windows, or are you confident enough I can provide the fix ? As I said I can't reach LSB/SSB ham bands and test by myself, because I only have a simple RTL-SDR.

cjcliffe commented 7 years ago

Sure I'll check out the HF on windows here; I'm sure it's fine but doesn't hurt to confirm 👍

cjcliffe commented 7 years ago

@vsonnier worked fine, I've removed the temporary code and pushed to master; closing this one up.