How to calculate EVM and MER if the noise in the signal has an RMS value of 0.4

I cant seem to find any information on how to do this problem,

For a 16 QAM mod signal how do i calculate EVM and MER if the noise in the signal has an RMS value of 0.4 and the phasor amplitude is 8v?

EVM(%) = [10^(-S/N(dB) / 20)]*100 = [10^(-10/20)]*100 = 5%

For Modulation Error Ratio you need the average power of the signal and of the noise. But MER generally is very close to EVM.

Thanks for your response!

I guess my question is how does the phasor amplitude and the RMS noise affect the EVM?

And how would your answer be different if you were trying to find the EVM of say an 8-PSK system?

Thank you!

Hi, vfone,
can you explain it clearly? from your equation, I can't derive the result.
In voltage, should it be, EVM=(Vn/Vs)^2 /20 *100=(0.4/4)^2 /20 *100=5%?

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Hi, vfone,
can you explain it clearly? from your equation, I can't derive the result.
In voltage, should it be, EVM=(Vn/Vs)^2 /20 *100=(0.4/4)^2 /20 *100=5%?