Re: Doppler

[Marcus D. Leech]

On 01/01/2024 16:11, Marcus Müller wrote:

Liya,

Doppler shift Δf is proportional to both speed and carrier frequency f₀

Δf = f₀ · v/c₀,

where v is the relative speed of your thing, and c₀ 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 Δf=10 GHz higher after 1s, your acceleration must been

a = Δf / f₀ · c₀ / 1s = 10 GHz / 150 GHz · 3·10⁸ m/s / s = 2/30 · 3·10⁸ m/s² = 1/15 c₀/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

    C/15 is actually about *twice* as fast as the fastest object we will
    ever have made.

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 <jiyajohnson10@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.