Abstract: This invention relates in general to a universal frequency synthesizer which is suitable for use in a phase-locked loop frequency synthesizer system comprising a voltage controlled oscillator, a reference oscillator and a low pass filter. The universal frequency synthesizer of the present invention is basically comprised of programmable divider circuitry and a phase detector.The universal frequency synthesizer is arranged to receive tuning data in serial format from an external source. The received tuning data is permanently stored within the universal frequency synthesizer and is used to establish the division ratio by which the output signal produced by the synthesizer's attendant voltage controlled oscillator and the reference signal produced by the synthesizer's attendant reference oscillator are divided before being provided to the signal and comparison inputs of the phase detector, respectively.