system phase noise calculation question
in the attached file bellow, I have some questions about phase noise calculation of a system
In the calculation that I highlighted I mixed up too much
why in first part the effect of multiplier phase noise has not been considered whereas in the second part the phase noise effect is considered?
would you please describe or introduce me some useful books?
THANKS IN ADVANCE
i am not following your question
The first digram is a little misleading, as it shows two different oscillators with the same phase noise: S1, so lets call one S1a and the other S1b
But after multiplication:
S1a+20*log( 2)
S1b+20*log( 4)
It is in there.
For your 1st question, the D1, D2, and D3 phase noise effect are ignored because they have little function. You can add them to the equations and you will find this point.
thanks for your replies
If the effect of D1'D2 and D3 can be Ignored,so why he did not ignore them in correlated formula?
and about biff44 reply I meant the difference between two formula for correlated and uncorrelated sources I meant
May this is because the two uncorrelated noise signals more or less compensate each other and that effect is not present in case of the same source (correlated).
Look at this simple Simulink model: from the scope it is clear that the upper diagram (correlated noise) is larger than lower.
In the 1st case, the phase noise is about -150dBm/Hz, so must consider D1 etc.
In the 2nd case, the phase noise is about -138dBm/Hz, you can add D1 etc to compare without them.