Radio frequency pulse width amplitude modulation system
AssigneeRCA Corporation
InventorLeonard Lewis Oursler, Jr.
Life of this patent
Estimating the term…
Abstract
Amplitude modulation of a radio frequency carrier is achieved by generating a rectangular wave pulse train at the carrier frequency, the pulses of which vary in width as a function of the amplitude of the audio input signal. The audio frequency input wave is subjected to an arc sine conversion process prior to the generation of the rectangular wave pulse train. The radio frequency pulse width modulated wave is amplified and then filtered to pass the fundamental radio frequency voltage and its modulation side bands.
Claims5
A system for amplitude modulating a carrier frequency signal in accordance with a modulating signal having a maximum frequency of f.sub.m, said system comprising:
- converting means responsive to said signal for generating an output signal which is the arc sine of said modulating signal:
- carrier generator means for generating a carrier signal having a substantially triangular waveform at said carrier frequency f.sub.c ;
- pulse width modulation means responsive to said carrier signal and said converting means output signal for generating a pulse width modulated signal,
- band pass filtering means responsive to said pulse width modulated signal for passing only signals from f.sub.c - f.sub.m to f.sub.c + f.sub.m with low attenuation whereby said carrier frequency is amplitude modulated by said modulating signal.
Dependencies are inferred from the claim text.