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 <patchvonbr...@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 >> >> > >