US4908784A — Method and apparatus for asynchronous time measur…

Claim 1

Independent Claim 150 words

Improved asynchronous time measurement apparatus, the improvement comprising: (a) a first clock producing a repetitive clock signal at a first frequency; (b) means connected to said first clock for counting complete clock cycles from a first event to a second event; (c) means for accumulating charge during the time from the first event to a predetermined edge of said clock signal and the time from the second event to a predetermined edge of said clock signal and separately comparing the accumulated charges relative to a linear charge characteristic table generated using calibration measurement events of random duration and random separation from one another, the table being stored in a memory, to determine corresponding times therefor; and (d) means for arithmetically processing the determined times corresponds to the first, second and complete clock cycle intervals to determine the magnitude of the elapsed time between the first event and the second event.

Claim 2

Dependent Claim 150 words

Improved asynchronous time measurement apparatus, the improvement comprising: (a) a first clock producing a repetitive clock signal at a first frequency; (b) means connected to said first clock for counting complete clock cycles from a first event to a second event; (c) means for accumulating charge during the time from the first event to a predetermined edge of said clock signal and the time from the second event to a predetermined edge of said clock signal and separately comparing the accumulated charges relative to a linear charge characteristic table generated using calibration measurement events of random duration and random separation from one another, the table being stored in a memory, to determine corresponding times therefor; and (d) means for arithmetically processing the determined times corresponds to the first, second and complete clock cycle intervals to determine the magnitude of the elapsed time between the first event and the second event.

Claim 3

Dependent Claim 57 words

Apparatus as set forth in claim 1 including (a) means for coupling a test fixture thereto, measuring the throughput delays of said test fixture and storing the measured delay values; and wherein (b) said processing means accounts for said delays as it processes the magnitude of the elapsed time between the first event and the second event.

Claim 4

Dependent Claim 21 words

Apparatus as set forth in claim 1 including means for selecting a first of a series of events to be detected.

Claim 5

Dependent Claim 15 words

Apparatus as set forth in claim 3 wherein the first event is a start event.

Claim 6

Dependent Claim 15 words

Apparatus as set forth in claim 3 wherein the first event is a stop event.

Claim 7

Dependent Claim 26 words

Apparatus as set forth in claim 1 including means for selecting which edge of said clock cycles said start and stop events are measured relative to.

Claim 8

Dependent Claim 23 words

Apparatus as set forth in claim 6 including means for selectively monitoring said start and stop events relative to a rising clock edge.

Claim 9

Dependent Claim 23 words

Apparatus as set forth in claim 6 including means for selectively monitoring said start and stop events relative to a falling clock edge.

Claim 10

Dependent Claim 54 words

Apparatus as set forth in claim 1 wherein said charge accumulation means includes means operative during a calibration period for pseudorandomly coupling sample event signals of random duration and separation from one another thereto and storing corresponding values in said memory of accumulated charge relative to time, which values collectively define a straight line.

Claim 11

Dependent Claim 21 words

Apparatus as set forth in claim 9 for measuring multiple ones of said sample signals for each value stored in memory.

Claim 12

Dependent Claim 87 words

Apparatus as set forth in claim 9 further including: (a) first and second counters; (b) means for periodically enabling said counters to produce sample event pulses of random duration and separation from one another; (c) means for discharging said charge accumulation means upon detection of a first pulse edge to a first potential and re-charging said charge accumulation means until an occurrence of the clock signal; and (d) means responsive to the termination of each sample charge accumulation for storing a corresponding time value in said memory.

Claim 13

Dependent Claim 32 words

Apparatus as set forth in claim 11 wherein a plurality of samples are measured at each value and stored in said memory and wherein said stored values define a rising straight line.

Claim 14

Dependent Claim 18 words

Apparatus as set forth in claim 9 wherein the linear stored charge characteristic corresponds to one clock cycle.

Claim 15

Dependent Claim 14 words

Apparatus as set forth in claim 13 wherein said clock cycle is ten nanoseconds.

Claim 16

Dependent Claim 123 words

Time measurement apparatus comprising: (a) a first clock producing a repetitive clock signal at a first frequency; (b) means enabled upon detection of a first signal edge for discharging to a first potential and recharging until the first following edge of said clock signal; (c) calibration means operative during a calibration period for addressably storing a plurality of measured voltages and a corresponding charging time developed by a charge storage means relative to a plurality of measured calibration sample events of random duration and random separation from one another; (d) means for addressably coupling the measured voltage developed during each measured event to said storage means to determine the magnitude of the time interval; and (e) means for displaying the determined time interval.

Claim 17

Dependent Claim 123 words

Time measurement apparatus comprising: (a) a first clock producing a repetitive clock signal at a first frequency; (b) means enabled upon detection of a first signal edge for discharging to a first potential and recharging until the first following edge of said clock signal; (c) calibration means operative during a calibration period for addressably storing a plurality of measured voltages and a corresponding charging time developed by a charge storage means relative to a plurality of measured calibration sample events of random duration and random separation from one another; (d) means for addressably coupling the measured voltage developed during each measured event to said storage means to determine the magnitude of the time interval; and (e) means for displaying the determined time interval.

Claim 18

Dependent Claim 22 words

Apparatus as set forth in claim 15 wherein said storage means contains voltage samples for a single period of said first clock.

Claim 19

Dependent Claim 59 words

Apparatus as set forth in claim 15 wherein said calibration means includes: (a) first and second counters; (b) means for periodically enabling said counters to produce sample signals of random width and separation from one another; and (c) means responsive to a termination of each sample charge accumulation for storing a corresponding time value in said addressable storage means.

Claim 20

Dependent Claim 45 words

Apparatus as set forth in claim 15 wherein said charge storage means includes: (a) means enabled by the end of an event for storing charge until the first following edge of said clock signal; and wherein (b) said time interval is determined by said means.

Claim 21

Dependent Claim 23 words

Apparatus as set forth in claim 15 including means for selectively enabling the initiation of event measurements for a selected plurality of events.

Claim 22

Dependent Claim 24 words

Apparatus as set forth in claim 19 wherein said processing means is programmed to compute a standard deviation of a plurality of measured events.

Claim 23

Dependent Claim 23 words

Apparatus as set forth in claim 19 wherein said processing means is programmed to compute an average of a plurality of measured events.

Claim 24

Dependent Claim 18 words

Apparatus as set forth in claim 19 including means for storing a maximum and minimum measured time intervals.

Claim 25

Independent Claim 135 words

A method for precisely measuring time including the steps of: (a) producing a repetitive clock signal at a first frequency; (b) counting complete clock cycles from a start event to a stop event; (c) accumulating charge during the time from the start event to a first following edge of said clock signal and the time from the stop event to the first following edge of said clock signal and separately comparing the accumulated charges relative to a linear charge characteristic table generated using calibration measurement events of random duration and random separation from one another, the table being stored in a memory, to determine corresponding times therefor; and (d) arithmetically processing the determined times of said start and stop event intervals and said complete clock cycle interval to determine the magnitude of the entire interval.

Claim 26

Independent Claim 135 words

A method for precisely measuring time including the steps of: (a) producing a repetitive clock signal at a first frequency; (b) counting complete clock cycles from a start event to a stop event; (c) accumulating charge during the time from the start event to a first following edge of said clock signal and the time from the stop event to the first following edge of said clock signal and separately comparing the accumulated charges relative to a linear charge characteristic table generated using calibration measurement events of random duration and random separation from one another, the table being stored in a memory, to determine corresponding times therefor; and (d) arithmetically processing the determined times of said start and stop event intervals and said complete clock cycle interval to determine the magnitude of the entire interval.

Claim 27

Dependent Claim 65 words

A method as set forth in claim 23 including the steps, during a calibration mode which occurs prior to the measurement of time, of pseudorandomly measuring sample event signals of random duration and separation from one another and storing the corresponding measured magnitudes 7 of accumulated charge in said memory and such that the sample magnitudes are reflective of a linear distribution relative to time.

Claim 28

Dependent Claim 25 words

A method as set forth in claim 24 including the steps of averaging a plurality of sample measurements and storing the average value in memory.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-03-12	1993-09-11	1994-03-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-03-12	1997-09-11	1998-03-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-03-12	2001-09-11	2002-03-13	$7700.00	Window Closed / Lapsed

Method and apparatus for asynchronous time measurement

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