What reference does the Phasemeter measure against?

Moku:Lab's Phasemeter measures the phase of the input signal against an internal oscillator, derived from the on-board clock. The frequency of the local oscillator is set by the 'Frequency' option under the 'Channels' pane. You can synchronize Moku:Lab with other electronics using the 10 MHz in and out ports on the backside of the device.