Amplitude modulator using variable width rectangular pulse generator

Apparatus for impressing the information in a varying level signal onto the fundamental frequency of a carrier signal, comprising:

• means for supplying a carrier signal;
• phase shift means for shifting said carrier signal in phase by a predetermined amount;
• comparator means connected to receive said carrier signal, said phase shifted carrier signal, and a varying level information signal, for producing first signal pulses when the amplitude of said carrier signal is greater than the amplitude of said information signal and second signal pulses when the amplitude of said phase shifted carrier signal is greater than the amplitude of said information signal;
• means connected to said carrier signal, said phase shifted carrier signal, said first signal pulses, and said second signal pulses for producing a first logical pulsed output signal when said carrier signal and said first signal pulses and said second signal pulses are low and for producing a second logical pulsed output signal when said phase shifted carrier, said first signal pulses and said second signal pulses are all low;
• and
• means for combining said first and second logical pulsed output signals to produce an output signal, whereby the fundamental frequency wave peaks will correspond to the information signal.

A method for impressing an information signal on a carrier signal, comprising the steps of;

• producing pulses when the carrier signal amplitude is greater than the information signal amplitude;
• causing said pulses to be produced at times corresponding to zero and .pi. radians on the time continuum of the carrier signal;
• inverting every other consecutive pulse of said produced signal, and producing a resultant signal therefrom;
• extracting the fundamental frequency from the resultant signal, whereby when the information signal is varied from zero to the maximum of the carrier signal, the fundamental frequency wave peaks correspond to the information signal.