US Patent 7355378 Source synchronous sampling

There is provided a method of source synchronous sampling, where a first clock signal of a first unit is synchronized to a second signal received from a second unit. The method includes determining a timing control signal on the base of the first clock signal and the second signal, generating an adjusted clock signal by adjusting the timing of the first clock signal corresponding to the timing control signal, and using the adjusted clock signal for sampling a signal received from the second unit. The second signal is a clock signal received from the second unit, the adjusted clock signal is used for sampling this clock signal itself, and a corresponding sampled clock signal is supervised to show proper clock functionality.