Re: Looking for a way to plot V_LSR vs intensity in GNU Radio

[Marcus Müller]

Hi Ellie,

being not versed in radioastronomy, I need to guess a bit here, but:
Is what you want essentially "how much power is there for any Doppler 
shift"?

If that's the case, and you're observing some known-frequency emission 
(say, a Hydrogen line) would that basically amount to:

1. Frequency-Shifting so that the zero-doppler frequency ends up at 0 Hz
2. transforming your time domain observation to frequency domain
3. labeling the frequency axis so that it tells velocity?

In that case, the Qt GUI frequency case would be a way to go. You can 
set the center frequency to do 1., it inherently does 2. and 3. can be 
achieved (ignoring wrong physical unit labels) by adjusting the 
bandwidth parameter.

Cheers,
Marcus

On 24/07/2020 17.09, Ellie White wrote:
> Hey all!
>
> Hope you're doing well and having a good summer. I apologize for 
> cross-posting here, but I wanted to pass this question by members of 
> both the SARA and GNU Radio communities to see what resources are out 
> there. This summer I'm working as an intern for Berkeley SETI Research 
> Center and I'm helping integrate the Allen Array with GNU Radio. I've 
> been collecting data with a USRP on site and I'm now attempting to plot it.
>
> My question is this: do any of you know of a method -- or a GNU Radio 
> module -- compatible with GR version 3.8 that allows you to plot raw 
> data from a USRP and get a plot of intensity versus velocity with 
> respect to the local standard of rest (V_LSR) -- instead of intensity 
> versus frequency, as given by the time sink block?
>
> Thanks so much for considering this, and for any ideas you have to 
> share! Have a nice day and take care.
>
> Cheers,
> Ellie
>
> --
> Ellie White
> Co-Director, Open Source Radio Telescopes
> Student at Marshall University
> 304-654-9381
> www.catseyeenterprises.net <http://www.catseyeenterprises.net>