Re: Doppler

-----BEGIN PGP SIGNATURE-----
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=m4Na
-----END PGP SIGNATURE-----
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.

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 <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.
>> image.png
>> image.png
>>