US Patent 10224942 Sub-sampling phase-locked loop

A sub-sampling phase-locked loop is described, which comprises a digital-to-time converter, a sampler module, an interpolator, and a voltage controlled oscillator. The digital-to-time converter is configured to provide a first delay signal (SDLY1) at a first point (t1) in time and a second delay signal (SDLY2) at a second point in time (t2). The sampler module is configured to provide a first sample (S1) of the oscillator output signal (SOUT) at the first point in time (t1) and a second sample (S2) of the oscillator output signal (SOUT) at the second point in time (t2). The interpolator is configured to provide a sampler signal (SSAMPL) by interpolating the first sample (S1) and the second sample (S2). The voltage controlled oscillator is configured to control the oscillator output signal (SOUT) based on the sampler signal (SSAMPL).