Re: Strange FFT AUDIO

[Marcus Müller]

Hi Kevin!

It does have that option: When you set it to "Type: Float", a choice "Spectrum 
Width:
Full" appears, which you can change to "Half".

Best,
Marcus

On 19.04.21 21:03, Kevin Reid wrote:
> On Mon, Apr 19, 2021 at 11:44 AM Alberto <alberto_gnuradio@libero.it
> <mailto:alberto_gnuradio@libero.it>> wrote:
> 
>     To obtain a real FFT i can use Float to Complex block ?
> 
> 
> Float to Complex will do the same thing you're seeing now — it just writes a 
> zero
> imaginary component into the stream.
> 
> If you need a signal with an actually one-sided spectrum you can use the 
> Hilbert block,
> which uses the Hilbert transform to generate a 90° phase shifted quadrature 
> component. But
> that is just wasted compute cycles unless your next signal processing step 
> actually needs
> that result. For viewing purposes, just ignore the other side of the 
> spectrum. (It would
> be nice if the QT GUI Frequency Sink had an option to hide it when given 
> float input, but
> as far as I know, it doesn't.)