A measurement instrument for measuring electrical characteristics of a device under test (DUT) includes a synchronization signal generator, a coarse phase detection counter and a fine phase detection counter. The synchronization signal generator is connectable with a receiver via a fiber optic cable and a duplexer configured to transmit a synchronization signal from the measurement instrument to the receiver and retransmit the received synchronization signal from the receiver to the measurement instrument. The coarse phase detection counter and the fine phase detection counter are configured to determine one or both of a distance from the receiver to the measurement instrument and a phase shift in the synchronization signal between the receiver and the measurement instrument.