P25 has two possible modulation modes. FM and LSM. FM is a constant magnitude demodulation where the receiver is only looking as phase changes. With LSM (linear simulcast modulation), the receiver is using mag / phase measurements to give a better decode for systems that use this type of modulation. Also known as Pi/4 D-QPSK modulation. I plan on adding a different display mode that will help to easily identify which modulation is in use.I think that was one of the scenarios when it happened. What exactly do the Demod modes do?