criterion456
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Hi,
In terms of PAR, higher order modulation scheme, more susceptible to nonlinearity distortion.
Besides, in terms of modulator, higher order modulation scheme, more susceptible to I/Q imbalance.
Thus, in theory, the EVM specification of higher order modulation scheme should be more relaxed.
Nevertheless, as shown in the figure below :
In LTE application, 64 QAM has more strict EVM requirement than QPSK ??
In other words,
For QPSK EVM test, it’s very easy to pass.
For 64 QAM EVM test, it’s very difficult to pass.
I am confused that why the specification is defined so.
Thanks~!!
In terms of PAR, higher order modulation scheme, more susceptible to nonlinearity distortion.
Besides, in terms of modulator, higher order modulation scheme, more susceptible to I/Q imbalance.
Thus, in theory, the EVM specification of higher order modulation scheme should be more relaxed.
Nevertheless, as shown in the figure below :
In LTE application, 64 QAM has more strict EVM requirement than QPSK ??
In other words,
For QPSK EVM test, it’s very easy to pass.
For 64 QAM EVM test, it’s very difficult to pass.
I am confused that why the specification is defined so.
Thanks~!!