Digital modulator with variations of phase and amplitude modulation

A modulator, comprising:

• a source of digital information signal;
• amplitude control signal generating means coupled to said source of digital information signal for generating a first digital amplitude control signal proportional to said digital information signal and for generating a second digital amplitude control signal equal in magnitude and opposite in polarity to said first digital amplitude control signal;
• a digital sawtooth signal generator for generating a digital sawtooth signal having a recurrence rate equal to the desired carrier frequency;
• first digital adding means coupled to said digital sawtooth signal generator and to said amplitude control signal generating means for adding together said digital sawtooth signal and said first digital amplitude control signal for generating a first phase-shifted digital sawtooth signal;
• second digital adding means coupled to said digital sawtooth signal generator and to said amplitude control signal generating means for adding together said digital sawtooth signal and said second digital amplitude control signal for generating a second phase-shifted digital sawtooth signal;
• first and second addressable memory means coupled to said first and second digital adding means, respectively, said first and second addressable memory means being addressed by said first and second phase-shifted digital sawtooth signal for generating first and second mutually phase-shifted sinusoidal analog signals;
• and
• summing means coupled to said first and second addressable memory means for adding together said first and second mutually phase-shifted analog sinusoidal signals for generating a carrier signal at said recurrence rate amplitude-modulated by said digital information signal.