Thank you for your reply. I see that I did not manage o explain very well what I wanted to do. The idea is that I want to set up a measurement system and for characterization I want to to measure transmission of various two port components (amplifiers, transmission lines, etc). Of course, I would normally use a network analyzer, which gives both the amplitude and phase of the transmission. The problem is that we do not have a network analyzer. But, since we have a spectrum analyzer, I was thinking of a different solution: use a noise source to inject some broadband noise at one port and the spectrum analyzer to measure the transmitted noise at another port. This measurement would give me the amplitude of the transmission for that two port system (unfotunately I will still miss the phase).
So in the end I would need a noise source to do the measurement. The requirement would be that it generates noise in a broadband (say from a few MHz to a few GHz) and that it has an output impedance which is 50 ohm over this band.
In the RF world one should have a deep pocket for purchasing test equipment. There are no cheap solutions for getting accurate and reliable test results. Any compromise in the price will come on the expense of quality
I completely agree with you.