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.pdfSome 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.
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/sOn 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
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