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

[Glen Langston]

Hi George and Marcus,

Yes I agree with Marcus, the Frequency Xlating FIR filter works surprisingly
well.

https://wiki.gnuradio.org/index.php?title=Frequency_Xlating_FIR_Filter

I’ve run some tests with placing (Simulating) audio tones at high frequencies 
ie 1MHz 
+ 880 Hz and the tone is perfectly preserved
at 880 Hz after XLating.

Glen

> On Feb 3, 2023, at 11:08 AM, Marcus D. Leech <patchvonbraun@gmail.com> wrote:
> 
> On 03/02/2023 11:04, Fabian Schwartau wrote:
>> Hi George,
>> 
>> I don't know if the Frequency sink can do that for you, but I guess it 
>> cannot.
>> One way is to mix the signal with a complex oscillation and a multiplier 
>> with the oscillator running at the negative frequency you wish to downshift 
>> the signal. Then low-pass filter and downsample the signal. You can then 
>> feed that into the Frequency sink and also set you oscillator frequency as 
>> offset frequency in the sink's settings.
>> 
>> Best,
>> Fabian
> That's pretty-much what the frequency-xlating FIR filter/FFT filter block is 
> for...
> 
> Also, sampling at 3GHz?  Into an ordinary computer?  Really?
> 
> 
>> 
>> Am 03.02.23 um 16:52 schrieb George Edwards:
>>> 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
>> 
>> 
> 
>