How to distinguish RFmx NR demodulated signal Pi/2 BPSK and QPSK

Updated Nov 7, 2022

Environment

Hardware

  • PXIe-5840

Software

  • RFmx NR

When we demodulate PI/2 BPSK signal and QPSK signal with RFmx NR , we will find that the demodulated constellation diagram is basically the same (4 points), which easily makes users doubt whether our software is demodulated correctly. So how do we distinguish the modulation of the demodulated signal?

1. Use RFmx Waveform Creator to send a PI/2 BPSK modulated signal
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2. Open RFmx NR SFP to view the demodulation information as follows
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3. How to distinguish the modulation mode of Signal and confirm whether the demodulation is correct, as follows:
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4. Correspondingly sent QPSK signal, you can see the corresponding demodulation information in RFmx NR

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We can see that although the demodulation constellations of Pi/2 BPSK and QPSK signals are similar, they are actually quite different. We can look up the modulation information of the demodulated signal in ModAcc Result to confirm whether the demodulation is correct;