This display shows the phase constellation of complex PSK signal, similar to Phase Plane module mentioned before, but in a complete different way.
Any phase state will create a steady, unmoving dot of pixels at one or more locations on the screen. The baud speed and the centre frequency have to be known und must be measured before as good and exact as possible. Depend on the phase constellation and the type of a psk signal the tuning must be correct within 20 Hz to enable automatic ‘locking’ into the signal. The symbol speed must be measured also within appr.1% of the correct value.
The Auto Tuning button will tune the center frequency around the chosen center frequency in small steps of 0.01 Hz up to 50 Hz higher and lower to find a locking point.
To demodulate and thus display 2DPSK or 4DPSK signals more clearly, select the correct demodulator as appropriate by activating the demodulator window, then choose from the pop up menu 2-DPSK or 4-DPSK.
This sample shows the phase constellation of a MIL110 serial signal