Re: [Discuss-gnuradio] Bandswitch and rf gain added to HF Explorer

[John Ackermann N8UR]

Thanks, Chuck -- sounds like useful new features.  I will download and play.

I meant to mention earlier in reference to the filter and the tradeoff
between skirts and CPU usage -- have you looked at the filtering scheme
used in the Flex-Radio SDR-1000 software?  I don't recall the exact
details right now, but it works something along the lines of doing an
FFT to convert the baseband signal back into the frequency domain, and
implementing the filter as a mask against the FFT bins, and then an
inverse FFT back to the time domain.  (I'm an idiot about this stuff, so
probably got some component of that wrong).  The end result is almost
"brick wall" filter skirts without using up too much CPU.

John
----
cswiger wrote:

>My HF Explorer project now has a slider for pga (I guess
>that corresponds roughly to an 'rf gain' control) and
>now sports 8 programmable bandswitch buttons to set the
>usrp center frequency. Just type the center freq in the
>text control so labled and hit enter to set it, or
>hit 'set' then one of the 8 buttons to program it into
>a button. Probably the most useful thing is to edit
>the script and hardwire in your favorite bands.
>
>I guess the next thing is to add selectable decimation -
>right now it's fixed at 100 for plus/minus 320Khz bandwidth.
>At least it should be a command line option - not sure
>if the fft display can be changed w/o having to restart
>everything.
>
>hf_explorer_10.py
>
>http://webpages.charter.net/cswiger/hfx/index.html
>
>
>--Chuck
>
>
>
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