Hi,
In first place, excuse my english...
I have some doubts, and maybe someone can help me.
In a superheterodyne receiver design, we used an isolator between each of the blocks of the system. I want to make a Noise Figure analysis by Spectrasys Simulation from mixer and for our intermediate frequency (3100Mhz). The graphic shows sharp fall and rise in Noise Figure (in the area of + - 70dB ), successively in each isolator. In the analysis of NF before the mixer we have not this problem.
Does this have Any clear explanation?
Thanks!
In first place, excuse my english...
I have some doubts, and maybe someone can help me.
In a superheterodyne receiver design, we used an isolator between each of the blocks of the system. I want to make a Noise Figure analysis by Spectrasys Simulation from mixer and for our intermediate frequency (3100Mhz). The graphic shows sharp fall and rise in Noise Figure (in the area of + - 70dB ), successively in each isolator. In the analysis of NF before the mixer we have not this problem.
Does this have Any clear explanation?
Thanks!
The PSA uses the Y Factor method for measuring noise figure. As the DUT gain goes to 0, the measurement uncertainty becomes really high. For this reason, a preamplifier is necessary to make good noise figure measurements with the PSA. You can either use the built in preamplifier (options 1DS or 110), or you can use an external preamplifier. However, if the pass loss is too high, you will still run into high uncertainties. Please refer to the Y Factor Method Application Note: http://cp.literature.agilent.com/litweb ... -3706E.pdf
Regards -