Abstract: A digital clock frequency multiplication and data serialization circuit for converting Q parallel data bits into a serial data stream is provided. A clock phase generator is coupled to receive the clock signal of the Q parallel data bits and output in response thereto Q synchronous clocks each of different phase. Logic circuitry is coupled to simultaneously receive the Q synchronous clocks and the Q parallel data bits. The Q synchronous clocks are used by the logic to gate a respective one of the Q parallel data bits such that the Q parallel data bits are sequentially output therefrom as a serial data stream. Circuits are provided for simultaneous frequency multiplication and return-to-zero data serialization and simultaneous frequency multiplication and nonreturn-to-zero data serialization. Further, digital clock frequency multiplication and synchronization circuits for converting a low frequency signal to a high frequency signal are described.