On 02/01/2024 05:01, Daniel Estévez wrote:
By the way,
Just for fun, there is this paper about what Doppler drift rates are
physically meaningful in RF. This topic comes up when doing de-drift
in narrowband SETI searches:
https://arxiv.org/pdf/1910.01148.pdf
Some of the objects at the bottom of Table 2 do indeed exceed 10 GHz/s
even for S-band carrier frequencies. But these are crazy situations,
such as a transmitter orbiting a neutron star very close to its surface.
Orbiting a transmitter around a neutron star, as one does for
entertainment. Or perhaps as a final-year project when attending
Galactic University....
Best,
Daniel.
On 01/01/2024 22:11, Marcus Müller wrote:
Liya,
Doppler shift Δf is proportional to both speed and carrier frequency
/f/₀
Δ/f/ = /f/₀ · /v///c/₀,
where /v/ is the relative speed of your thing, and /c/₀ is the speed
of light.
The highest frequencies we can, so far, do radio communications on,
are in the range of f₀=150 GHz.
So, assuming you do communications on 150 GHz, for your Doppler shift
to be Δ/f=/10 GHz higher after 1s, your acceleration must been
/a = /Δ/f / f/₀ · /c/₀ / 1s = 10 GHz / 150 GHz · 3·10⁸ m/s / s = 2/30
· 3·10⁸ m/s² = 1/15 /c/₀/s.
The fastest object mankind has ever built is the Parker Solar Probe,
which will burn up while it spirals into the sun, at a maximum
velocity of ca 1/15 of the speed of light. It takes it years to reach
that speed, not 1s.
So, you're assuming you're seeing a doppler from a satellite rotating
around earth that sees a relative acceleration higher than a
"satellite" around the sun actively being pulled into the sun by the
sun's immense gravity.
That sadly makes no physical sense!
Best regards,
Marcus
On 01.01.24 07:51, Jiya Johnson wrote:
Yes I want to use 10GHz/s
On Sat, Dec 30, 2023, 4:05 PM Jiya Johnson <jiyajohnso...@gmail.com>
wrote:
Greetings everyone,
https://github.com/daniestevez/reu-2023/tree/main/doppler
I went through these grc files and tried to do drift_simulation, i
am not getting the way to get 10GHz/s using inspectrum and
frequency sink slope calculation i have attached the grc and
screenshots.
image.png
image.png
