US Patent 11005644 Time stamp generation

Embodiments of the present disclosure include techniques for generating accurate time stamps. In one embodiment, a first timing reference signal corresponding to a first clock domain is combined with a first clock signal corresponding to a second clock domain to produce a second timing reference signal that includes quantization noise. The second timing reference signal is filtered to remove the quantization noise and generate a filtered timing reference signal. The filtered timing reference signal may be sampled in the second clock domain to obtain a time stamp. In one embodiment, a phase locked loop (PLL) is used as the filter. The PLL may generate first and second ramps that correspond to time. One of the ramps may be sampled to obtain a time stamp, for example.