Question
I would like to know how to test noise figure of AD8348. Can you give some idea
about this? They would like to consider using AD8348 in mobile TV application.
I also would like to know whether there is successful application already in
this kind of application.
Answer
For testing the NF of AD8348, you can use any spectrum analyzer such as FSIQ,
FSQ or any signal analyzer. 1. Test the noise floor of the analyzer itself.
Noise floor should be dBm/Hz, suppose it is A1. 2. Test the noise floor of
AD8348 at far frequency offset such as 20MHz offset, suppose it is A2. 3.
Calculate the difference of above two, suppose it is A3=A2-A1. 4. According to
different A3, using the attached excel form, get the calibration factor,
suppose it is A4. 5. Calibrate the contribution of analyzer noise floor from
the result of AD8348 noise floor, we get A5=A2-A4. 6. Calculate the NF of
AD8348 using the formula NF=A5-(-174dBm/Hz)