Periodicity verification circuit

Claim 2

Apparatus for detecting an aperiodic characteristic of a signal characterized by a plurality of cycles, each of said plurality of cycles having a time duration characterized by a beginning and an end occurring when said signal crosses a predetermined reference value with a predetermined slope, comprising: first means for providing a first voltage proportional to the time duration of a first cycle of said plurality of cycles; second means for providing a second voltage proportional to the time duration of a second cycle of said plurality of cycles; and third means responsive to said first means and said second means for providing an output when said first voltage does not bear a predetermined relationship to said second voltage, said third means comprising a comparator for comparing said first voltage to a sum of a first predetermined fraction of said second voltage and a second predetermined fraction of a reference voltage and including means for varying said reference voltage in proportion to said time duration of alternate cycles of said plurality of cycles upon an occurrence of a predetermined number of said plurality of cycles.

Claim 3

Apparatus as recited in claim 1 wherein: said first and said second means each comprises an integrator for providing a substantially constant current to a capacitor during said time duration of said first and said second cycles respectively.

Claim 4

Apparatus as recited in claim 1 wherein: said first and said second means comprise alternate cycles of said plurality of cycles and including reset means operatively connected to said first and said second means to restart the operation thereof after a predetermined number of cycles.

Claim 5

Apparatus as recited in claim 3 further comprising: gating means for rendering said third means inoperative during each said first and second cycle and for rendering said third means operative upon an occurrence of the end of each said second cycle.

Claim 6

Apparatus for verifying the periodicity of a signal comprising: first means for providing a first binary signal characterized by being alternately in either a first state or a second state; said first means changing state in response to said signal crossing a predetermined reference in a predetermined direction; second means for providing a second binary signal characterized by being alternately in either said first state or said second state and further characterized by having a state different from said first binary signal; third means responsive to said first means for providing a first voltage proportional to a time integral of said first binary signal; fourth means responsive to said second means for providing a second voltage proportional to a time integral of said second binary signal; and fifth means responsive to said third means and said fourth means for providing a warning signal when said first voltage and said second voltage do not bear a predetermined relationship, said third means comprising a comparator for comparing said first voltage to a sum of a first predetermined fraction of said second voltage and a second predetermined fraction of a reference voltage, and including means for varying said reference voltage in proportion to said time duration of alternate cycles of said plurality of cycles upon an occurrence of a predetermined number of said plurality of cycles.

Claim 7

Apparatus for verifying the periodicity of a signal comprising: first means for providing a first binary signal characterized by being alternately in either a first state or a second state; said first means changing state in response to said signal crossing a predetermined reference in a predetermined direction; second means for providing a second binary signal characterized by being alternately in either said first state or said second state and further characterized by having a state different from said first binary signal; third means responsive to said first means for providing a first voltage proportional to a time integral of said first binary signal; fourth means responsive to said second means for providing a second voltage proportional to a time integral of said second binary signal; and fifth means responsive to said third means and said fourth means for providing a warning signal when said first voltage and said second voltage do not bear a predetermined relationship, said third means comprising a comparator for comparing said first voltage to a sum of a first predetermined fraction of said second voltage and a second predetermined fraction of a reference voltage, and including means for varying said reference voltage in proportion to said time duration of alternate cycles of said plurality of cycles upon an occurrence of a predetermined number of said plurality of cycles.

Claim 8

Apparatus as recited in claim 5 further comprising: a sixth means for rendering said fifth means responsive to said first voltage and said second voltage upon each occurrence of said first binary signal making a transition from said second state to said first state.

Claim 9

Apparatus for verifying the periodicity of a signal comprising: dividing means responsive to said signal for providing a pair of output signals alternately having a first state and a second state, one of said output signals being in said first state when the other of said output signals is in said second state; wherein said output signals each change state in response to said signal passing through a predetermined reference value in a predetermined direction; integrating means responsive to said pair of output signals for providing a pair of period signals; and comparator means for providing a comparator output when one of said pair of period signals bears a predetermined relationship to the other of said pair of period signals, said comparator means including reference means for providing a reference signal proportional to a number of times a predetermined one of said pair of output signals has been in said first state and said predetermined relationship is one of said pair of period signals being greater than a first predetermined fraction of said reference signal plus a second predetermined fraction of the other of said pair of period signals.

Claim 10

Apparatus for verifying the periodicity of a signal comprising: dividing means responsive to said signal for providing a pair of output signals alternately having a first state and a second state, one of said output signals being in said first state when the other of said output signals is in said second state; wherein said output signals each change state in response to said signal passing through a predetermined reference value in a predetermined direction; integrating means responsive to said pair of output signals for providing a pair of period signals; and comparator means for providing a comparator output when one of said pair of period signals bears a predetermined relationship to the other of said pair of period signals, said comparator means including reference means for providing a reference signal proportional to a number of times a predetermined one of said pair of output signals has been in said first state and said predetermined relationship is one of said pair of period signals being greater than a first predetermined fraction of said reference signal plus a second predetermined fraction of the other of said pair of period signals.