Synthesis of Nucleoside Derivatives Containing Benzophenoxazinone Moiety

Systems and methods for measuring the characteristics of voltage controlled oscillators within these circuits and initializing the circuits without coupling circuitry to the voltage control node that could introduce noise at this node. One embodiment includes a PLL circuit having a charge pump and control circuitry for driving the charge pump, where the control circuitry is configured to provide "up" and "down" signals to the charge pump in a normal operational mode or a test/initialization mode. In the normal mode, the control circuitry passes signals received from a phase frequency detector through to the charge pump as the up and down signals. In the test/initialization mode, the control circuitry overrides at least one of the signals received from the phase frequency detector to drive the charge pump to generate a selectable test voltage which is used by a voltage controlled oscillator to generate an output signal at a corresponding frequency.