I executed QPSK example provided by Mathwork in Simulink, the received baseband spectrum of the signal is changing amplitude a lot! I looked at the I and Q time domain received data, the envelope of both I and Q varying unexpected and there are many spikes on the I and Q data.
Does anybody know what are the causes of spikes in the received IQ data?
what are the causes of I/Q envelope variations over time? Could it be discontinuity on the ADC and DAC?
Please find attached received I/Q data.
[edited by: Arashjafari at 3:30 PM (GMT -4) on 28 Jun 2022]