In a measurement system, a signal probing circuit may provide probed signals by probing voltages and currents and/or incident and reflected waves at a port of a device under test (DUT). A multi-channel receiver structure may include receivers that receive two probed signals from the signal probing hardware circuit, each receiver having its own sample clock derived from a master clock and further having a respective digitizer for digitizing a corresponding one of the two probed signals. A synchronization block, external to the receivers and including a reference clock derived from the master clock, may enable the two probed signals to be phase coherently digitized across the receivers by synchronizing the respective sample clocks of the receivers while the reference clock is being shared with the receivers. A signal processing circuit may then process the phase coherently digitized probed signals.