Slope detector

Claim 2

Apparatus, to determine if the slope of an input signal equals or exceeds a predetermined value in a predetermined time, comprising: first means, responsive to said input signal, for generating a first signal which is substantially equal to the input signal; second means, responsive to the first signal and the input signal for producing a second signal which is equal to the difference between the input signal and the first signal; third means, responsive to the second signal, for generating a third signal which matches the second signal; fourth means, responsive to the second signal and the third signal, for producing a fourth signal which is equal to the difference between the second signal and the third signal; fifth means, responsive to the fourth signal, for producing a fifth signal whenever the fourth signal equals or exceeds a predetermined value; and sixth means, responsive to the fifth signal, for producing an output signal whenever the fifth signal is present for a predetermined time.

Claim 3

Apparatus, to determine if the slope of an input signal equals or exceeds a predetermined value in a predetermined time, comprising: an analog to digital converter, responsive to the input signal, which produces an output nearly equal to the input signal, during a first time period; a first differential amplifier which produces a coarsely zeroed signal equal to the difference between the input signal and the output of the analog to digital converter; a sample and hold circuit for producing an output which matches the output of the first differential amplifier, during a second time period; a second differential amplifier for producing a finely zeroed output equal to the difference between the output of the first differential amplifier and the output of the sample and hold circuit; a comparator, responsive to the output of the second differential amplifier and a reference voltage, for producing an output whenever the output of the second differential amplifier equals or exceeds the reference voltage; and a counter for recording the presence of the comparator output during a third time period and for producing an output signal whenever the comparator output is present during three consecutive third time periods.

Claim 4

Apparatus, to determine if the slope of an input signal equals or exceeds a predetermined value in a predetermined time, comprising: an analog to digital converter, responsive to the input signal, which produces an output nearly equal to the input signal, during a first time period; a first differential amplifier which produces a coarsely zeroed signal equal to the difference between the input signal and the output of the analog to digital converter; a sample and hold circuit for producing an output which matches the output of the first differential amplifier, during a second time period; a second differential amplifier for producing a finely zeroed output equal to the difference between the output of the first differential amplifier and the output of the sample and hold circuit; a comparator, responsive to the output of the second differential amplifier and a reference voltage, for producing an output whenever the output of the second differential amplifier equals or exceeds the reference voltage; and a counter for recording the presence of the comparator output during a third time period and for producing an output signal whenever the comparator output is present during three consecutive third time periods.

Claim 5

Apparatus according to claim 2 further including a timing generator for controlling said analog to digital converter, said sample and hold circuit and said counter.