Chip to chip time synchronization

In an embodiment, an apparatus includes an integrated circuit (IC) chip configured to receive a timing signal and a reference clock signal and generate a first reference time signal based on the timing signal and the reference clock signal. The IC chip includes a clock phase lock loop (PLL) configured to generate and provide a second reference clock signal at a higher frequency than the reference clock signal; the IC chip is further configured to generate a second reference time signal based on the first reference time signal and the second reference clock signal. The second reference time signal specifies a count of a number of cycles of the second reference clock signal starting from a particular cycle of the second reference clock signal. The second reference time signal has a finer count resolution than the first reference time signal for a same time period.