Encoding analog signals into digital signals using a triangular reference

Claim 1

A system for encoding an input analog signal having a highest frequency component f H and comprising: means for supplying square wave signals having a given period T and upper and lower levels of constant and equal duration; means for supplying triangular signals in phase with said square wave signals and having said given period T less than 1/f H ; modulator means responsive to said triangular signals and to said input analog signal for producing pulses at a rate equal to 1/T and whose widths are proportional to the amplitude of said input analog signal at the times of equality therebetween; and gating means receiving as input signals thereto said square wave signals and said pulses for producing an output signal at one level when the logical values of the input signals thereto are the same and of another level when the logical values of the input signals thereto are different.

Claim 2

A system for encoding an input analog signal having a highest frequency component f H and comprising: means for supplying square wave signals having a given period T and upper and lower levels of constant and equal duration; means for supplying triangular signals in phase with said square wave signals and having said given period T less than 1/f H ; modulator means responsive to said triangular signals and to said input analog signal for producing pulses at a rate equal to 1/T and whose widths are proportional to the amplitude of said input analog signal at the times of equality therebetween; and gating means receiving as input signals thereto said square wave signals and said pulses for producing an output signal at one level when the logical values of the input signals thereto are the same and of another level when the logical values of the input signals thereto are different.

Claim 5

A system for communicating analog input signals having a highest frequency component f H and comprising, in combination: transmission means responsive to said analog input signals for producing digital output signals, said transmission means including; square wave signal generating means for producing square wave signals having a given period less than 1/f H and upper and lower levels of contant and equal duration; triangular signal generating means for producing signals in phase with said square wave signals and having said given period; comparator means responsive to said analog input signals and to said triangular signals for producing output signals having a first or second logical value dependent upon the relative magnitudes of said analog input signals and said triangular signals; gating means for Exclusive ORing said square wave signals with the output signals from said comparator means to produce digital signals; and receiving means responsive to said digital signals from said gating means for reproducing said analog input signals, including means for producing a voltage proportional to the time duration of adjacent levels of said received digital signals.

Claim 6

A system for communicating analog input signals having a highest frequency component f H and comprising, in combination: transmission means responsive to said analog input signals for producing digital output signals, said transmission means including; square wave signal generating means for producing square wave signals having a given period less than 1/f H and upper and lower levels of contant and equal duration; triangular signal generating means for producing signals in phase with said square wave signals and having said given period; comparator means responsive to said analog input signals and to said triangular signals for producing output signals having a first or second logical value dependent upon the relative magnitudes of said analog input signals and said triangular signals; gating means for Exclusive ORing said square wave signals with the output signals from said comparator means to produce digital signals; and receiving means responsive to said digital signals from said gating means for reproducing said analog input signals, including means for producing a voltage proportional to the time duration of adjacent levels of said received digital signals.

Claim 9

A method for generating balanced pulse width modulated signals from an input analog signal having a highest frequency component f H and comprising the steps of: generating square wave signals having a given period less than 1/f H and having upper and lower levels of constant and equal duration; generating triangular signals in phase with said square wave signals and having said given period; modulating said triangular signals with said input analog signals to produce signals; and exclusive-ORing said digital signals and said square wave signals to produce balanced pulse width modulated digital signals.

Claim 10

A method for generating balanced pulse width modulated signals from an input analog signal having a highest frequency component f H and comprising the steps of: generating square wave signals having a given period less than 1/f H and having upper and lower levels of constant and equal duration; generating triangular signals in phase with said square wave signals and having said given period; modulating said triangular signals with said input analog signals to produce signals; and exclusive-ORing said digital signals and said square wave signals to produce balanced pulse width modulated digital signals.