Re: How to display a part of the GRC spectrum?

[Marcus Müller]

First of all, that's a high sampling rate!

You would want to shift the signal (e.g using the "Rotator" block, or 
just by using a signal source at the shift frequency and a (conjugate) 
multiplication), then decimate it by a factor of 3 GHz / 8 MHz = 375.

From a point of view of designing the decimator, decimation by 375 is 
quite a mouthful - it requires a filter transition width of 
significantly less than 1/375 of the input Nyquist rate. So, it would 
seem advisable to do this decimation in a cascade of decimators – in the 
extreme case, decimation by 3, by 5, by 5, by 5.

Best regards,
Marcus

On 2/3/23 16:52, George Edwards wrote:
> Dear GNURadio Community,
>
> Let's say I build a GRC flowgraph operating at a sample rate of 3 GHz 
> and wish to display the spectrum over the fixed range of 1GHz +/- 
> 4MHz, how do I get the QT GUI Frequency sink to plot over this range?
>
> Thank you!
>
> George