A time-to-digital converter (TDC) can have a resolution that is finer than the propagation delay of an inverter. In one example, a fractional-delay element circuit receives a TDC input signal and generates therefrom a second signal that is a time-shifted facsimile of a first signal. The first signal is supplied to a first delay line timestamp circuit (DLTC) and the second signal is supplied to a second DLTC. The first DLTC generates a first timestamp indicative of a time between an edge of a reference input signal to the TDC and an edge of the first signal. The second DLTC generates a second timestamp indicative of a time between the edge of the reference input signal and an edge of the second signal. The first and second timestamps are combined and together constitute a high-resolution overall TDC timestamp that has a finer resolution than either the first or second timestamps.