Patent US5177344A successfully refreshed from Google Patents.
US5177344A
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Method and appparatus for enhancing a randomly varying security characteristic
Assignee: DocuSystems Inc
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Filing: 1990-10-05
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Granted: 1993-01-05
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Expires: 2010-10-05
Abstract
Abstract A randomly varying modulated current is generated and used to drive a magnetic write head in an apparatus for enhancing a randomly varying magnetic security characteristic of a medium. The write head can be positioned adjacent a fluid magnetic slurry for the purpose of altering the location of the various magnetic particles therein in a random fashion. The slurry can then be hardened thermally or using ultraviolet dryers. A circuit which can generate the randomly variable current for the read head includes a modulator which receives a first randomly variable signal and a second, different randomly varying signal which modulates the first signal.
Inventors
- 👤 Kevin J. Pease
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:53
CPC Classifications
G; G07; G07F; G07F7/00; G07F7/08; G06; G06K; G06K1/00; G06K1/12; G06K1/125; G06K19/00; G06K19/06; G06K19/08; G06K19/10; G06K19/12; G06Q; G06Q20/00; G06Q20/30; G06Q20/34; G06Q20/347; G07F7/0806; G07F7/0813; G07F7/086; G07F7/12; G07F7/125
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
88 words
An apparatus for creating an enhanced random magnetic characteristic in a fluid magnetic region carried on an underlying medium, the apparatus comprising: a signal modulator with a modulatable signal input, a modulation signal input and a modulated signal output; a source of substantially random electrical signals coupled to said modulatable signal input; a source of substantially random modulating signals coupled to said modulation input: a magnetic write head coupled to said modulated signal output and located adjacent to the fluid magnetic region for altering the magnetic characteristics thereof.
Claim 2
Independent Claim
88 words
An apparatus for creating an enhanced random magnetic characteristic in a fluid magnetic region carried on an underlying medium, the apparatus comprising: a signal modulator with a modulatable signal input, a modulation signal input and a modulated signal output; a source of substantially random electrical signals coupled to said modulatable signal input; a source of substantially random modulating signals coupled to said modulation input: a magnetic write head coupled to said modulated signal output and located adjacent to the fluid magnetic region for altering the magnetic characteristics thereof.
Claim 3
Dependent Claim
31 words
An apparatus as in claim 1 with said source of random signals including circuitry for generating an electrical signal having white noise-like frequency characteristics at least for a predetermined frequency range.
Claim 4
Independent Claim
21 words
An apparatus as in claim with said modulator including circuitry for altering a frequency parameter of said substantially random, electrical signals.
Claim 5
Dependent Claim
17 words
An apparatus as in claim 1 with said source of modulating signals including a voltage controlled oscillator.
Claim 6
Independent Claim
70 words
A method of generating an enhanced random, magnetic characteristic in a magnetic slurry supported on an underlying medium comprising: providing a magnetic slurry; generating a first electrical signal having a random-like characteristic; generating a second electrical signal having a different random-like characteristic; modulating the first signal with the second signal and, in response thereto, producing a third signal; and altering the magnetic characteristics of the slurry with the third signal.
Claim 7
Independent Claim
70 words
A method of generating an enhanced random, magnetic characteristic in a magnetic slurry supported on an underlying medium comprising: providing a magnetic slurry; generating a first electrical signal having a random-like characteristic; generating a second electrical signal having a different random-like characteristic; modulating the first signal with the second signal and, in response thereto, producing a third signal; and altering the magnetic characteristics of the slurry with the third signal.
Claim 8
Dependent Claim
17 words
A method as in claim 5 including hardening the slurry after its magnetic characteristics have been altered.
Claim 9
Dependent Claim
17 words
A method as in claim 5 including drying the slurry after its magnetic characteristics have been altered.
Claim 10
Dependent Claim
17 words
A method as in claim 5 with said second electrical signal generated with a randomly varying frequency.
Claim 11
Dependent Claim
17 words
A method as in claim 5 with said first electrical signal generated with a randomly varying amplitude.
Claim 12
Dependent Claim
32 words
A method as in claim 5 including in the altering step generating an electro-magnetic field responsive to the third signal, moving the slurry and applying the electro-magnetic field to the moving slurry.
Claim 13
Dependent Claim
17 words
A method as in claim 5 including applying radiant energy to the magnetic slurry to harden same.
Claim 14
Independent Claim
69 words
A method of generating an enhanced random, security characteristic in a slurry magnetic medium comprising: providing an enhanceable slurry magnetic medium; generating a first electrical signal having a random-like characteristic; generating a modulating signal; synchronizing the electrical signal with the modulating signal; modulating the synchronized electric signal; and altering the random characteristics of the slurry magnetic medium with the synchronized and modulated electrical signal and then hardening the medium.
Claim 15
Independent Claim
69 words
A method of generating an enhanced random, security characteristic in a slurry magnetic medium comprising: providing an enhanceable slurry magnetic medium; generating a first electrical signal having a random-like characteristic; generating a modulating signal; synchronizing the electrical signal with the modulating signal; modulating the synchronized electric signal; and altering the random characteristics of the slurry magnetic medium with the synchronized and modulated electrical signal and then hardening the medium.
Claim 16
Independent Claim
119 words
An apparatus for creating an enhanced random characteristic in a slurry magnetic medium prior to hardening that medium, the apparatus comprising: a signal modulator with a signal input port, a modulation input port, and a modulated signal output port; a source of substantially random electrical signals coupled to said modulator signal input port; circuitry, coupled to said modulation input port and to said source, for synchronizing an electrical signal from said source with an input to said modulation input port; and an output device coupled to said modulated signal output port and located adjacent to the slurry magnetic medium for altering the random characteristics thereof in response to said modulated signal output while the medium is still a slurry.
Claim 17
Independent Claim
119 words
An apparatus for creating an enhanced random characteristic in a slurry magnetic medium prior to hardening that medium, the apparatus comprising: a signal modulator with a signal input port, a modulation input port, and a modulated signal output port; a source of substantially random electrical signals coupled to said modulator signal input port; circuitry, coupled to said modulation input port and to said source, for synchronizing an electrical signal from said source with an input to said modulation input port; and an output device coupled to said modulated signal output port and located adjacent to the slurry magnetic medium for altering the random characteristics thereof in response to said modulated signal output while the medium is still a slurry.
References Cited (Backward Citations)
US3788617A
Cited
US3636318A
Cited
US3599153A
Cited
GB1331604A
Cited
GB1308331A
Cited
CH529398A
Cited
US3894756A
Cited
US3959630A
Cited
US3790754A
Cited
US4114032A
Cited
CH569333A5
Cited
US4058839A
Cited
GB1535340A
Cited
US4034211A
Cited
US4218674A
Cited
US4066910A
Cited
US4092526A
Cited
US4094462A
Cited
GB1541579A
Cited
GB1546053A
Cited
US4180837A
Cited
US4215812A
Cited
DE2829778C2
Cited
US4303949A
Cited
US4469937A
Cited
US4450348A
Cited
US4423415A
Cited
US4451535A
Cited
US4390905A
Cited
US4649265A
Cited
US4508752A
Cited
US4620727A
Cited
US4547393A
Cited
US4661983A
Cited
US4630845A
Cited
US4518627A
Cited
US4874633A
Cited
US4861619A
Cited
US4806740A
Cited
US4837426A
Cited
US4906988A
Cited
JPS63273272A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-01-05 | 1996-07-06 | 1997-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-01-05 | 2000-07-06 | 2001-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-01-05 | 2004-07-06 | 2005-01-05 | $7700.00 | Window Closed / Lapsed |