Hi all,
is there any problem with this test setup?
1) To measure NF we directly measure NF as shown.
2) To measure Gain, we first measure S21 from path 1, then measure S21 from path 2.
Next we measure S11 from path 2.
We can then calculate the voltage gain of the buffer.
Finally we can calculate the voltage gain of the DUT.
Does this seem right? The only assumption is that the capacitance of the output pad is negligibly small. Note that when I measure path 1, the pad at the input of path 2 is open circuit and vice versa.
thanks,
Aaron