Re: [Discuss-gnuradio] swapping spectrum on the FCD

[Alexandru Csete]

On Sat, Dec 15, 2012 at 11:55 AM, Stefano Sinagra <address@hidden> wrote:
> Hi,
> I'm using a FunCube Dongle to FFT monitor the 69MHz if of my Yaesu FT950 ham
> transceiver.
> Unfortunately spectrum is shown inverted, with signals 10kHz above my center
> frequency shown instead 10kHz below.
>
> This isn't something new and I've seen I/Q swapping options in other
> instances.
> Is there any fairly simple way to do it in GnuRadio when using FCD as a
> source?

The I/Q order in the FCD source should be correct unless there is some
other swapping happening in the audio setup of your OS.
Are you sure it's not some frequency error you are experiencing? Do
the signals move in the wrong direction when you change the frequency?

To answer your question, yes, it is very simple to swap I/Q: you take
a complex-to-float and float-to-complex blocks and cross wire, i.e.
real->imag and imag->real them.

Alex