Methods and apparatus for generating phase-shifted clock signals from a reference clock, connecting the phase-shifted clock signals to a counter module so that the phase-shifted clock signals change values in counters in the counter module, and combining the values in the counters to generate an output signal corresponding to an amount of time. One or more events can be detected at a time corresponding to the output signal. In embodiments, pulses can be transmitted and received at a measure time to evaluate connected devices.