Patent US3699253A successfully refreshed from Google Patents.
US3699253A
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Coordinate determining device employing a second order difference signal to determine approximate cursor position
Assignee: Bendix Corp
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Filing: 1971-07-06
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Granted: 1972-10-17
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Expires: 1991-07-06
Abstract
Abstract Cursor position is determined by providing three signals that vary cyclically at different rates in response to cursor position. The three provided signals are used to provide two first order difference signals and one second order difference signal. The first order difference signals vary substantially slower than the three cyclic signals and thus indicate cursor position over a distance in which the cyclic signals change through more than one cycle. The second order difference signal varies at a rate substantially slower than the two first order differences and thus indicates cursor position over a distance in which the two first order signals vary through more than one cycle. A digital output signal indicating cursor position is provided by using the second order difference to form the most significant portion of the output, by using one of the first order differences to form a less significant portion, and by using one of the three cyclic signals to provide the least significant output signal.
Inventors
- 👤 Morris David Freedman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 03:23
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/046
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
216 words
A device for determining the coordinate position of a cursor comprising: signal providing means for providing first, second, and third coordinate position indicating signals that vary cyclically in response to cursor displacement, said second signal varying slower than said first signal so that the difference between said first and second signals is directly proportional to cursor displacement for a distance in which said first and second signals vary through more than one cycle, and said third signal varying slower than said second signal so that the difference between said second and third signals is directly proportional to cursor displacement for a distance in which said second and third signals vary through more than one cycle; and subtracting means for providing a first order difference between said first and second signals, a second first order difference between said second and third signals, and a second order difference between said first and second differences, said first order differences varying cyclically in response to cursor displacement, said second order difference varying at a rate substantially slower than said first order differences and thereby being directly proportional to cursor displacement for a distance in which said first order differences vary through more than one cycle; and means for receiving said second order difference and providing an output indicating cursor position.
Claim 2
Independent Claim
216 words
A device for determining the coordinate position of a cursor comprising: signal providing means for providing first, second, and third coordinate position indicating signals that vary cyclically in response to cursor displacement, said second signal varying slower than said first signal so that the difference between said first and second signals is directly proportional to cursor displacement for a distance in which said first and second signals vary through more than one cycle, and said third signal varying slower than said second signal so that the difference between said second and third signals is directly proportional to cursor displacement for a distance in which said second and third signals vary through more than one cycle; and subtracting means for providing a first order difference between said first and second signals, a second first order difference between said second and third signals, and a second order difference between said first and second differences, said first order differences varying cyclically in response to cursor displacement, said second order difference varying at a rate substantially slower than said first order differences and thereby being directly proportional to cursor displacement for a distance in which said first order differences vary through more than one cycle; and means for receiving said second order difference and providing an output indicating cursor position.
Claim 3
Dependent Claim
126 words
The device of claim 1 in which: said signal providing means include means defining first, second, and third sets of measuring intervals along a selected dimension, the intervals of said second set being slightly larger than the intervals of said first set and slightly smaller than the intervals of said third set; said first signal identifies the relative position on said cursor within the interval of said first set proximate said cursor; said second signal identifies the relative position of said cursor within the interval of said second set proximate said cursor; said third set being slightLy larger than said intervals of said second set, and said third signal identifies the relative position of said cursor within the interval of said third set proximate said cursor.
Claim 4
Dependent Claim
80 words
The device of claim 2 in which: said first, second, and third signals each comprise linearly varying, digital signals, said first signal changing by one cycle in response to cursor displacement equal to one interval of said first set, said second signal changing by one cycle in response to cursor displacement equal to an interval of said second set, and said third signal changing by one cycle in response to cursor displacement equal to one interval of said third set.
Claim 5
Dependent Claim
30 words
The device of claim 3 in which said means defining said first, second, and third sets of intervals comprise electrically conductive grid means disposed on a single electrically nonconductive backing.
Claim 6
Dependent Claim
93 words
The device of claim 3 in which: said third difference varies cyclically in response to cursor displacement; said first order and second order differences provide a unique combination of values for each cursor position over a distance in which said third difference signal varies through more than one cycle; and said output providing means also receives one of said first order differences and provides an output determined by the combination of received values to indicate cursor position over a distance in which said second order difference changes through more than one complete cycle.
Claim 7
Dependent Claim
214 words
The device of claim 5 in which: said second order difference is permitted to have only a finite number of different values for any particular value of said one first order difference in the absence of any error; said output providing means also compensates for errors in said second order difference and includes: means for determining each value that said second order difference is permitted to have for a value of said one of said first order differences in the absence of any error and for comparing said second order difference with each of said permitted values to determine the permitted difference value closest to said second order difference; and means for utilizing said closest permitted difference value to provide a readout signal indicating cursor position, there being only one permitted value closest to said second order difference for a distance in which said second order difference changes through more than one complete cycle, the permitted difference being closest to said second order difference being unaffected by errors in said second order difference smaller than the change in said second order difference signal caused by cursor displacement changing said one first order difference signal by 1/2E cycles, where E equals the number of cycles through which said second order difference is permitted to change.
Claim 8
Dependent Claim
191 words
The device of claim 6 in which: corresponding edges of a plurality of intervals of said first and said second sets align at a plurality of positions, the distance between said positions of alignment being defined by the equation: D N1A N2B where: D the distance between positions of alignment; A and B the lengths of each of the intervals of said first and said second sets, respectively; and N1 and N2 the smallest whole number integers satisfying the ratio N1/N2 B/A corresponding edges of a plurality of intervals of said second and third sets align at a plurality of positions, the distance between the second and third set positions being defined by the equation: D'' N3B N4C where: C the length of each interval of said third set; and N3 and N4 the smallest whole number integers satisfying the ratio N3/N4 C/B; and said closest permitted diffErence value uniquely identifies approximate cursor position over the distance defined by the equation: D'''' N5(N1A) N6(N3B) where: D'''' the distance over which said closest permitted difference uniquely identifies approximate cursor position; and N5 and N6 the smallest integers satisfying the ration N5/N6 N3/N2.
Claim 9
Dependent Claim
51 words
The device of claim 7 in which said utilization includes summing means for receiving said closest permitted value of said second order difference, said one first order difference, and one of said three coordinate position indicating signals, and combining the three received signals to provide an output precisely indicating cursor position.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |