Abstract: Disclosed is a number controlled, modulated, oscillator employing a modulation selector for receiving a digital number for use for frequency modulation or for phase modulation, a tuning network for receiving another digital number in a variety of forms, and a frequency modulator for adding the value of the modulation selector number to that of the tuning network number. Also, the oscillator employs a phase accumulator for adding the value of the frequency modulator sum to that of a number already stored in the phase accumulator and replacing the stored number with the phase accumulator sum at each of a series of times specified by a clocking signal. Further, the oscillator employs a phase modulator for adding the value of the number stored in the phase accumulator to that of the modulation selector number and an output selector developing the 1's compliment of the phase modulator sum and for selecting either the phase modulator sum or the complimented number.