McWitty
They are claiming to handle amplitude based modulation, an example is PAM-4.
There are levels of complexity to modulation. NRZ is like someone signalling you with a flashlight by turning it on and off. Amplitude modulation is like the flashlight having different brightness levels to signal. Coherent -- well my analogy just fell apart.
Coherent is like if your kitchen clock itself spun around all day. 12 o clock wouldnt always be up. You would have to mentally correct the phase angle and do a "coherent" demod of the time.
Coherent is required for the QAM type modulations that look like dots on a checkerboard. If the checkerboard is spinning you have to determine say where is the true up-down and left-right in order to decide the correct bits.
rogue