A digital fractional phase detector (200) is provided to realize a frequency synthesizer architecture (100) that naturally combines transmitter modulation capability with a wideband all-digital PLL modulation scheme to maximize a digitally-intensive implementation by operating in a synchronous phase domain. Synchronous logic is provided across a digitally controlled VCO (104) and is synchronous to the VCO output clock by implementing a timing adjustment in association with a reference calculation to allow a frequency control word to contain both channel information and transmit modulation information. The digital fractional phase detector (200) is capable of accommodating a quantization scheme to measure fractional delay differences between the significant edge of the VCO output clock (110) and a reference clock by using a time-to-digital converter (201) to express the time difference as a digital word for use by the frequency synthesizer.