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Post subject: measuring The Noise Figure of WLAN
Receiver RF Front-end
Posted: Thu Jan 21, 2010 7:31 am
Joined: Wed Aug 16, 2006
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 approach.
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 Figure.
I will be trying this out
in the LAB. If anyone finds any fault in this method thebn
please share your thoughts.