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WLAN 802.11b measurement using EXA with VSA software

Question asked by thomas9003 on Jul 9, 2013
Latest reply on Jul 10, 2013 by DaveHornbeck

I'm using EXA with VSA software to do some measurements with my WLAN 802.11b module at 5210MHz. (attached screenshots)

I have some questions below.

1)     In continuous mode transmission, the EVM is about 35%.
a)     In VXA mode, when the adaptive equalizer is on using Filter Length=22 and convergence=0.01, the EVM reduced to less than 3%.
b)     In VSA mode, when the adaptive equalizer is on, it doesn’t seems to converge with the same settings.

2)     In burst mode transmission, using IF trigger, similar issue was observed as before, however, it seems that the EVM measurements can be improved without using adaptive equalizer by changing the RRC alpha factor and symbol timing, and the optimum evm is about 8% when using RRC factor at 0.25 and symbol timing at 0.22.

3)     What should be the recommended setting for using the adaptive equalizer? Should it be turned on during production testing? Any app notes on this?

4)     The module tested do not implement a RRC filter type, instead it is a 5th order inverse chebyshev low pass filter. What should be the recommended channel filter setting used then?

5)     By setting the symbol timing, will it have any impact on the production testing?

Hope you can help.