I am trying to simulate a system in Simulink, where i am trying to generate a QPSK modulated waveform (As you can see in the image below)
I am getting a proper constellation after the Fiilter block (as you can see in the image below)
But after the DUC unit, i am getting something
The spectrum i am getting afetr both the stages are shown below
After Root Cosine
After DUC unit
In the image below, we can see the DUC block setting
Please help me to resolve this issue.