How do I determine the MDS and sensitivity of the AD9361 and in general a receiver based on a non-ideal IQ demodulator? For instance sensitivity S=-174 +NF +10log(BW) + S/N of detector to meet BER. But this assumes an ideal IQ demodulator. So if my receiver requires a detector SNR of 5 to meet my BER with an ideal IQ demodulator, how do I now determine the sensitivity if I factor in an 17.8 % EVM (SNR of 15)? And if I use a digital quadrature error correction algorithm (QMC) can I recapture or come close to achieving the sensitivity of the receiver with an ideal IQ demodulator?
QEC error correction algorithm takes care of this imbalance between IQ. For AD9361 Quadrature gain and phase error are 2% and 2 degree typ respectively. The impact of this will be much less than a dB in terms of SNR.
>>The impact of this will be much less than a dB in terms of SNR.
But in terms of 'unwanted sideband' the impact is -40 ... -34 dB
Sorry my mistake.
For AD9361 Quadrature gain and phase error are 0.2% and 0.2 degree typ respectively and image rejection is ~ -50dBc
According the formula for the receiver's sensitivity:S=-174 +NF +10log(BW) + S/N, the BW here is the bandwidth of the signal being received and sampled to the IQ data which is the same as a bandwidth of the channel selected by the filters inside AD9361 or the BW refers here as an analog RF front-end bandwidth before an AD9361 RF input?
The bandwidth here depends on the standard that is used, which is actually taken care by channel filtering in baseband.