US4080515A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Successively electromagnetically scanned x-y grid conductors with a digitizing system utilizing a free cursor or stylus
Assignee: GTCO CORP
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Filing: 1977-01-12
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Granted: 1978-03-21
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Expires: 1997-01-12
Abstract
Abstract A position digitizing device in which a cursor, moveable within a field generated by successively activated grid wires, developes a voltage from the field and, in conjunction with conditioning circuits, yields the electrical intelligence required to indicate its position with a high degree of precision. Currents are successively passed through parallel grid lines at discretely separate distances, the resultant successively positioned fields successively inducing voltages at the cursor coil output dependent upon the position of the cursor in relation to the actuated grid line. Conditioning equipment to which the cursor output is coupled mixes the cursor output with a reference and introduces circuitry responsive to the rate at which the grid currents are successively stepped to translate the cursor output to a time variant wave form. A reference point developed from that wave form is then used to permit a precision clock to relate the distance of the cursor from a grid line to the time needed to reach the reference point. Cursor position then becomes a function of precisely generated pulses accumulated in a counter.
Inventors
- 👤 Raymond W. Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:53
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/046
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
212 words
Apparatus for determining the position of a selected point on a grid comprising an oscillator; a cursor including a coil moveable on said grid; first means for supplying a signal from said oscillator to X and Y conductors in said grid; switching means for scanning said X and Y conductors so as to provide said signal to said conductors individually in sequence; said coil in said cursor detecting said signals in said conductors; a filter coupled to the output of said coil; second means for supplying a reference signal from said oscillator; third means for frequency modulating said reference signal with the output of said filter; frequency modulation discriminator means coupled to the output of said third means; a second filter coupled to the output of said discriminator means for producing a signal envelope each time said conductors are scanned; fourth means coupled to the output of said second filter for detecting the zero crossing point of said signal envelope; X and Y counters; fifth means coupling the output of said fourth means to said counters; and sixth means for coupling the output of said oscillator to said counters; whereby the outputs of said fourth means and said oscillator are operable to stop each counter at a value indicative of cursor position.
Claim 2
Dependent Claim
212 words
Apparatus for determining the position of a selected point on a grid comprising an oscillator; a cursor including a coil moveable on said grid; first means for supplying a signal from said oscillator to X and Y conductors in said grid; switching means for scanning said X and Y conductors so as to provide said signal to said conductors individually in sequence; said coil in said cursor detecting said signals in said conductors; a filter coupled to the output of said coil; second means for supplying a reference signal from said oscillator; third means for frequency modulating said reference signal with the output of said filter; frequency modulation discriminator means coupled to the output of said third means; a second filter coupled to the output of said discriminator means for producing a signal envelope each time said conductors are scanned; fourth means coupled to the output of said second filter for detecting the zero crossing point of said signal envelope; X and Y counters; fifth means coupling the output of said fourth means to said counters; and sixth means for coupling the output of said oscillator to said counters; whereby the outputs of said fourth means and said oscillator are operable to stop each counter at a value indicative of cursor position.
Claim 3
Dependent Claim
13 words
The apparatus of claim 1 wherein said oscillator input comprises a crystal oscillator.
Claim 4
Dependent Claim
39 words
The apparatus of claim 1 wherein said first means for supplying said signal comprises a crystal oscillator; a divider coupled to the output of said crystal oscillator; and a decoder and filter coupled to the output of said divider.
Claim 5
Dependent Claim
16 words
The apparatus of claim 1 wherein said frequency modulation discriminator means comprises a phase locked loop.
Claim 6
Dependent Claim
25 words
The apparatus of claim 1 wherein said switching means comprises a clock decoder; and a counter for detecting the initiation and termination of each scan.
Claim 7
Dependent Claim
18 words
The apparatus of claim 1 further comprising means for positioning said coil a predetermined distance from said grid.
Claim 8
Dependent Claim
202 words
Apparatus for determining the position of a selected point on a grid having X and Y conductors comprising an oscillator; a cursor including a coil moveable on said grid; first means for supplying a signal from said oscillator to said coil; switching means for scanning said X and Y conductors in sequence so as to detect the output signal of said coil; a filter coupled to the output of said switching means; second means for supplying a reference signal from said oscillator; third means for frequency modulating said reference signal with the output of said filter; frequency modulation discriminator means coupled to the output of said third means; a second filter coupled to the output of said discriminator means for producing a signal envelope each time said conductors are scanned; fourth means coupled to the output of said second filter for detecting the zero crossing point of said signal envelope; X and Y counters; fifth means coupling the output of said fourth means to said counters; and sixth means for coupling the output of said oscillator to said counters; whereby the outputs of said fourth means and said oscillator are operable to stop each counter at a value indicative of cursor position.
Claim 9
Dependent Claim
202 words
Apparatus for determining the position of a selected point on a grid having X and Y conductors comprising an oscillator; a cursor including a coil moveable on said grid; first means for supplying a signal from said oscillator to said coil; switching means for scanning said X and Y conductors in sequence so as to detect the output signal of said coil; a filter coupled to the output of said switching means; second means for supplying a reference signal from said oscillator; third means for frequency modulating said reference signal with the output of said filter; frequency modulation discriminator means coupled to the output of said third means; a second filter coupled to the output of said discriminator means for producing a signal envelope each time said conductors are scanned; fourth means coupled to the output of said second filter for detecting the zero crossing point of said signal envelope; X and Y counters; fifth means coupling the output of said fourth means to said counters; and sixth means for coupling the output of said oscillator to said counters; whereby the outputs of said fourth means and said oscillator are operable to stop each counter at a value indicative of cursor position.
Claim 10
Dependent Claim
13 words
The apparatus of claim 7 wherein said oscillator input comprises a crystal oscillator.
Claim 11
Dependent Claim
39 words
The apparatus of claim 7 wherein said first means for supplying said signal comprises a crystal oscillator; a divider coupled to the output of said crystal oscillator; and a decoder and filter coupled to the output of said divider.
Claim 12
Dependent Claim
16 words
The apparatus of claim 7 wherein said frequency modulation discriminator means comprises a phase locked loop.
Claim 13
Dependent Claim
25 words
The apparatus of claim 7 wherein said switching means comprises a clock decoder; and a counter for detecting the initiation and termination of each scan.
Claim 14
Dependent Claim
18 words
The apparatus of claim 7 further comprising means for positioning said coil a predetermined distance from said grid.
Claim 15
Dependent Claim
187 words
Apparatus for determining the position of a selected point on a grid comprising an oscillator; a cursor including a coil moveable on said grid; means for supplying a signal from said oscillator to X and Y conductors in said grid; switching means for scanning said X and Y conductors so as to provide said signal to said conductors individually in sequence; said coil in said cursor developing a signal envelope each time said grid is scanned; a filter coupled to the output of said coil; means for supplying a reference signal from said oscillator; means for frequency modulating said reference signal with the output of said filter; means for detecting the null in said cursor signal envelope; means for coupling said modulated output to said means for detecting said null; X and Y counters; means for coupling the output of said means for detecting said null to said counters; and means for coupling the output of said oscillator to said counters; whereby the outputs from said means for detecting said null and said oscillator are operable to stop each counter at a value indicative of cursor position.
Claim 16
Dependent Claim
187 words
Apparatus for determining the position of a selected point on a grid comprising an oscillator; a cursor including a coil moveable on said grid; means for supplying a signal from said oscillator to X and Y conductors in said grid; switching means for scanning said X and Y conductors so as to provide said signal to said conductors individually in sequence; said coil in said cursor developing a signal envelope each time said grid is scanned; a filter coupled to the output of said coil; means for supplying a reference signal from said oscillator; means for frequency modulating said reference signal with the output of said filter; means for detecting the null in said cursor signal envelope; means for coupling said modulated output to said means for detecting said null; X and Y counters; means for coupling the output of said means for detecting said null to said counters; and means for coupling the output of said oscillator to said counters; whereby the outputs from said means for detecting said null and said oscillator are operable to stop each counter at a value indicative of cursor position.
Claim 17
Dependent Claim
18 words
The apparatus of claim 13 wherein said means for detecting said null comprises a phase locked loop discriminator.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |