Digital method of pulse width modulation

Claim 1

A method for producing a binary pulse width modulated output signal from an amplitude modulated digital data signal having a fixed frequency in accordance with detected times of interception between said digital data signal and a reference signal, said method comprising the steps of: generating with means said reference signal in the form of uniform amplitude incrementations each of constant time interval to approximate as linear analog ramp signal, and having selected maximum and minimum amplitudes, comparing with means the value of said digital data signal at a selected interval to the values of said incremental reference signal at a first interval and a second subsequent interval for detecting if said data signal and said reference signal will intercept when said reference signal is incremented between the values corresponding to said first and said second subsequent intervals of said reference signal, generating with means a correction signal whose value is proportional to the time interval between the beginning of said first interval of said reference signal and the time at which said digital data signal would intercept said approximated linear analog ramp signal if an intercept between said digital data signal and said reference waveform upon incrementation to the value corresponding to said second interval is detected, and controlling with means the transition time of said binary pulse width modulated output signal from one binary state to its other binary state at each intercept depending upon the value of said proportional correction signal.

Claim 2

A method for producing a binary pulse width modulated output signal from an amplitude modulated digital data signal having a fixed frequency in accordance with detected times of interception between said digital data signal and a reference signal, said method comprising the steps of: generating with means said reference signal in the form of uniform amplitude incrementations each of constant time interval to approximate as linear analog ramp signal, and having selected maximum and minimum amplitudes, comparing with means the value of said digital data signal at a selected interval to the values of said incremental reference signal at a first interval and a second subsequent interval for detecting if said data signal and said reference signal will intercept when said reference signal is incremented between the values corresponding to said first and said second subsequent intervals of said reference signal, generating with means a correction signal whose value is proportional to the time interval between the beginning of said first interval of said reference signal and the time at which said digital data signal would intercept said approximated linear analog ramp signal if an intercept between said digital data signal and said reference waveform upon incrementation to the value corresponding to said second interval is detected, and controlling with means the transition time of said binary pulse width modulated output signal from one binary state to its other binary state at each intercept depending upon the value of said proportional correction signal.