What I'm thinking of is a 2 way communication (voice communication) between two systems which are in motion. (like 100 km/h difference)
Will the data transmission and reception be disturbed, by how much?
Is this present in modern transreceivers?
I'm not fixed on a particular frequency. In that case, what difference will it make for a 400 MHz vs a 2.4 GHz carrier on data throughput?
Background:
I read something about Doppler shift. How much noise will be induced due to this effect?
I found 2 questions similar in the same forum (not same questions but talking about similar communication stuff). I'll add the links once I get my hands on my PC.
Best Answer
I don't know why everyone else is focusing on the carrier frequency. The data throughput is a question about the modulating frequency (i.e., baud rate).
The Doppler effect applies to modulation, as well. If the transmitter is moving toward the receiver, the baud rate is increased by a factor of 1.000000092, and if it is moving away, the factor is 0.999999908 — the baud rate is reduced.
There is also relativistic time dilation, which is based on what fraction of the speed of light the relative velocity is. If it takes Δt seconds to transmit some number of symbols, they will arrive at the receiver in Δt' seconds:
$$\Delta t' = \frac{\Delta t}{\sqrt{1 - \frac{v^2}{c^2}}}$$
So yes, the data throughput from the receiver's point of view is reduced by a very tiny fraction at the speed you're talking about.
For a speed of 27.778 m/s, that fraction is about 4.28669×10-15, giving a ratio of 0.9999999999999957.