Hello,
I understand that you want to demodulate an OQPSK-modulated signal. To demodulate the OQPSK signal, please follow these steps:
- Matched Filtering: Apply a matched filter to your received signal. The matched filter should have the same pulse shape as the OQPSK modulator (raised-cosine or half-sine filtering). Then sample the matched filter outputs at 2 samples per symbol (since you want to downsample later).
- Downsampling: Downsample the matched filter outputs to achieve the desired samples per symbol (in your case, 1 sample per symbol). You can use every other sample from the matched filter outputs for both the in-phase (I) and quadrature (Q) components.
- Decision Logic: Implement decision logic to map the downsampled I and Q samples back to the transmitted symbols. Compare the I and Q samples to the OQPSK constellation points (±A/sqrt(2), ±A/sqrt(2)) to determine the transmitted bits.
Please adjust any delays introduced during the modulation process.
I hope this helps!
