Installation guide

Generation of a transport stream for DVB and realisation of a HF-modulated DVB-signal
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Question5
What is the Constellation Diagram? What do we see?
The constellation diagram is a representation of the received errors. It shows the way the symbols are
being received. We can see the received symbols on the I/Q plane (In phase, Quadrature). Each point is a
received symbol. The more symbols received in the same place, the redder is the graph.
Question6
Why don’t we receive all the different symbols in the center of the cells?
Because of the noisy environment.
Question7
If the EVM was 0, how would the constellation diagram look like?
It would look like there is only one red dot per cell. This is because all the symbols would reach the exact
same point, as there would be no noise at all.
Question8
What is the Eye Diagram?
The eye diagram is the representation of all the symbols that are being received overlapped.
It has 4 features: the opening, the overshoot, the width and the closure.
Question9
Is the Eye Diagram received in good condition? What problems do you see?
No, it has a lot of noise. We see distortion because of the noise, peak distortion, jitter effects and
intersymbolic interferences.
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