I want to measure the Noise Figure of
the RF Front-end (Switch+LNA+Diplexer) for a WLAN
receiver implemented using Discrete components.
I don't have a Noise source and Noise Figure
meter to chatracterize the Noise Figure of this
assembly. I was thinking of trying the following
1. Since I don't have a vector
signal generator, I will use a WLAN transmitter
that I designed. Attenuate the output power to -60dBm
(burst power). Feed this signal to a Vector Signal
Analyzer and measure the EVM. Let us call the EVMin
2. Remove the VSA and connect the RF Receiver
Front-end. This will feed the Transmitted signal
at the antenna port of the Receiver. Now at the
other end of the receiver chain connect the VSA
and record the EVM. Let us say that this is EVMout.
3. Can I assume that the EVM will be proportional
to the SNR at low input power levels. if yes, then
can I use the difference between EVMin and EVMout
as an estimate of the Receiver RF Front-end Noise
I will be trying this out in the
LAB. If anyone finds any fault in this method thebn
please share your thoughts.