How to measure GND noise on the PCB ?
I have a board of GSM phone. the performance of phase error is very bad . I want to check the cleanlily of GND , so meausre the noise on the GND with Spectrum analyzer , Ir is right ? any other problems to make the phase error bad ?
How are you measuring the noise?
Are you connecting the probe and the GND reference both to the Board?
I suggest take a signal from "Earth== Chassis" and use it as ground reference. You may connect this to the ground of the board and then probe at the ground of the board. I am not so sure of this but I use it sometimes.
Phase noise:
Check the power supply pin. Filter it. This should solve 80% of your problems.
i think that if you would to use a spectrum analyzer you must to create a probe whit loop but you can find a radate emission.
if you have i think that is better to use an active probe.
Othervise you need to have a oscillope you must to have mathematical funztion as fft or power pectral density so you can find if spurious frequency are in ground plane.
Bye
G.
The phase error is measured with CMU200 which simulating GSM Base . I think the bad phase error is related to the GND or Power Cleanity , so with spectrum analyzer , i want to find some noise spectrum added to the gnd or power.