US4525751A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Disc record with tapered groove
Assignee: RCA Corp
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Filing: 1982-08-27
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Granted: 1985-06-25
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Expires: 2002-08-27
Abstract
Abstract A video disc record of the constant angular velocity type (CAV) includes a spiral groove of constant pitch formed in a band on a surface thereof. The groove has a substantially constant nominal vertical dimension and vertical displacements which taper monotonically from an outer radius of the band to an inner radius. One component of the vertical displacement of the groove conveys an FM carrier wave of constant amplitude and relatively high frequency representative of picture information. A second component of the vertical displacement conveys one or more lower frequency FM carrier waves representative of sound information. The amplitude of the second component varies monotonically as a function of the groove radius within the record band to provide a disc having an improved audio FM carrier-to-noise ratio with no substantial perceptible increase in undesirable sound beat effects in images displayed when the disc is played. A mastering system exemplary of the method of forming the grooved disc includes variable gain units in an audio FM carrier wave processing path of the system.
Inventors
- 👤 Edward J. Freeman
- 👤 John E. Economou
- 👤 John G. Pecorari
- 👤 Gunter John
- 👤 Jerome B. Halter
- 👤 Jack E. James
- 👤 Richard M. Castle
- 👤 Richard C. Palmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:05
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; H04N5/7605; G; G11; G11B; G11B20/00; G11B20/02; G11B20/06; G11B23/00; G11B23/0057; H04N5/903
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
83 words
A method for producing a video disc record comprising the steps of: (a) providing respective sound and picture signals, each modulated on a respective FM carrier wave; (b) combining said FM carrier waves to provide a composite mastering signal; (c) forming a spiral groove in a master substrate in accordance with said composite mastering signal; and (d) varying the amplitude of said sound FM carrier wave without varying the amplitude of said picture FM carrier wave while forming said groove in said substrate.
Claim 2
Independent Claim
83 words
A method for producing a video disc record comprising the steps of: (a) providing respective sound and picture signals, each modulated on a respective FM carrier wave; (b) combining said FM carrier waves to provide a composite mastering signal; (c) forming a spiral groove in a master substrate in accordance with said composite mastering signal; and (d) varying the amplitude of said sound FM carrier wave without varying the amplitude of said picture FM carrier wave while forming said groove in said substrate.
Claim 3
Dependent Claim
17 words
The method recited in claim 1 wherein the amplitude of the FM carrier wave is varied monotonically.
Claim 4
Dependent Claim
31 words
The method recited in claim 1 wherein the step of varying the amplitude of the sound FM carrier wave is performed prior to the step of combining said FM carrier waves.
Claim 5
Dependent Claim
55 words
The method recited in claim 2 wherein the step of monotonically varying the amplitude of the sound FM carrier wave comprises: providing a control signal manifestation which varies as a function of time; and applying said control signal manifestation to a variable transmission device interposed in a path for conducting said sound FM carrier wave.
Claim 6
Dependent Claim
33 words
The method recited in claim 2 wherein the step of monotonically varying the amplitude of the sound FM carrier wave is performed in discrete steps at predetermined intervals from a given starting time.
Claim 7
Dependent Claim
32 words
The method recited in claim 2 wherein the step of monotonically varying the amplitude of the sound FM carrier wave is performed at a continuous rate beginning at a predetermined starting time.
Claim 8
Dependent Claim
31 words
The method recited in claim 2 wherein the step of monotonically varying the amplitude of the sound FM carrier wave is performed in discrete steps corresponding to predetermined radial groove locations.
Claim 9
Dependent Claim
34 words
The method recited in claim 2 wherein the step of monotonically varying the amplitude of the sound FM carrier wave is performed as a substantially continuous function of the radius of said spiral groove.
Claim 10
Dependent Claim
38 words
The method recited in claim 1 further comprising the steps of: sensing the radius of said spiral groove during said forming step; and altering the amplitude of said sound FM carrier wave in accordance with the sensed radius.
Claim 11
Dependent Claim
39 words
The method recited in claim 1 further comprising the steps of: sensing the radius of said spiral groove during said forming step; and altering the amplitude of said spiral groove in discrete steps in accordance with the sensed radius.
Claim 12
Dependent Claim
43 words
The method as recited in claim 1 further comprising the steps of: sensing the radius of said spiral groove during said forming step; and altering the amplitude of said spiral groove continuously in accordance with the sensed radius prior to said forming step.
Claim 13
Dependent Claim
63 words
The method as recited in claim 2 wherein the step of monotonically varying the amplitude of said FM carrier wave includes reducing the amplitude of said FM carrier from a given value at an outer radius of a band of said disc record to a lesser value at an inner radius of said band to cause said groove to exhibit a predetermined taper.
Claim 14
Dependent Claim
40 words
The method as recited in claim 12 wherein the rate of variation of said amplitude of said FM carrier wave is controlled such that said predetermined taper is a linear function of the radius of said groove within said band.
Claim 15
Dependent Claim
40 words
The method as recited in claim 12 wherein the rate of variation of said amplitude of said FM carrier wave is controlled such that said predetermined taper is a non-linear function of the radius of said groove within said band.
Claim 16
Dependent Claim
46 words
The method as recited in claim 12 wherein the rate of variation of said amplitude of said sound FM carrier wave is controlled such that said predetermined taper is substantially equal to 1 dB/inch over at least a portion of the grooved surface of said disc.
Claim 17
Dependent Claim
55 words
The method as recited in claim 1 further comprising the step of initially adjusting the amplitude of said sound FM carrier wave to a predetermined level such that amplitude variations of said groove at an outer radius of said record and attributable to said sound FM carrier wave are substantially equal to 140 Angstroms peak-to-peak.
Claim 18
Dependent Claim
75 words
A video disc record for playback at a substantially constant angular velocity, said record comprising: a disc having a spiral groove formed in at least one surface thereof, said groove having a substantially constant pitch between an outer radius thereof and an inner radius, thereof, said groove having a substantially constant nominal depth and peak-to-peak vertical variations monotonically tapered from a maximum value at said outer radius to a minimum value at said inner radius.
Claim 19
Dependent Claim
75 words
A video disc record for playback at a substantially constant angular velocity, said record comprising: a disc having a spiral groove formed in at least one surface thereof, said groove having a substantially constant pitch between an outer radius thereof and an inner radius, thereof, said groove having a substantially constant nominal depth and peak-to-peak vertical variations monotonically tapered from a maximum value at said outer radius to a minimum value at said inner radius.
Claim 20
Dependent Claim
30 words
A video disc record as recited in claim 17 wherein said vertical variations comprise a substantially constant picture FM carrier wave component and a variable sound FM carrier wave component.
Claim 21
Dependent Claim
26 words
A video disc record as recited in claim 18 wherein said sound FM carrier wave component exhibits an amplitude variation of substantially 1 dB per inch.
Claim 22
Dependent Claim
35 words
A video disc record as recited in claim 18 wherein the vertical variations attributable to said sound FM carrier wave component at the outer radius of said record are substantially equal to 140 Angstroms peak-to-peak.
Claim 23
Dependent Claim
36 words
A video disc record as recited in claim 18 wherein the vertical variations attributable to said sound FM carrier wave component exhibit a minimum value of substantially 100 Angstroms at the innermost radius of said record.
Claim 24
Dependent Claim
19 words
A video disc record as recited in claim 17 wherein the taper of said groove variations exhibits discrete steps.
Claim 25
Dependent Claim
19 words
A video disc record as recited in claim 17 wherein the taper of said groove variations is substantially linear.
Claim 26
Dependent Claim
18 words
A video disc record as recited in claim 17 wherein the taper of said groove variations is convex.
Claim 27
Dependent Claim
18 words
A video disc record as recited in claim 17 wherein the taper of said groove variations is concave.
Claim 28
Dependent Claim
80 words
A disc record, comprising: a base material having a spiral groove formed in at least one surface thereof, said groove having a constant pitch and a nominal vertical dimension which is substantially constant over at least a portion of the disc surface defining a band having an inner radius and an outer radius, said groove having vertical displacements within said band which taper monotonically from a maximum dimension at said outer radius to a minimum dimension at said inner radius.
Claim 29
Dependent Claim
80 words
A disc record, comprising: a base material having a spiral groove formed in at least one surface thereof, said groove having a constant pitch and a nominal vertical dimension which is substantially constant over at least a portion of the disc surface defining a band having an inner radius and an outer radius, said groove having vertical displacements within said band which taper monotonically from a maximum dimension at said outer radius to a minimum dimension at said inner radius.
Claim 30
Dependent Claim
57 words
A disc record as recited in claim 26 wherein the vertical displacement of said spiral groove at any point between said radii comprises the sum of a first substantially invariant vertical component and a second variable vertical component, the dimension of said second component decreasing monotonically from said outer radius to said inner radius of said band.
Claim 31
Dependent Claim
20 words
A disc record as recited in claim 27 wherein said second vertical component is representative of an FM carrier wave.
Claim 32
Dependent Claim
28 words
A disc record as recited in claim 28 wherein said FM carrier wave exhibits amplitude variations on the order of about 1 dB per inch within said band.
Claim 33
Dependent Claim
18 words
A disc record as recited in claim 26 wherein the taper of said groove displacements exhibits discrete steps.
Claim 34
Dependent Claim
18 words
A disc record as recited in claim 26 wherein the taper of said groove displacements is substantially linear.
Claim 35
Dependent Claim
17 words
A disc record as recited in claim 26 wherein the taper of said groove displacements is convex.
Claim 36
Dependent Claim
17 words
A disc record as recited in claim 26 wherein the taper of said groove displacements is concave.
Claim 37
Dependent Claim
21 words
A disc record as recited in claim 27 wherein said second component exhibits a taper of about 14 Angstroms per inch.
Claim 38
Dependent Claim
23 words
A disc record as recited in claim 27 wherein said second component has a maximum value on the order of about 140 Angstroms.
Claim 39
Dependent Claim
23 words
A disc record as recited in claim 27 wherein said second component has a minimum value on the order of about 100 Angstroms.
Claim 40
Dependent Claim
35 words
A disc record as recited in claim 27 wherein said second component is representative of the sum of two FM carrier waves and wherein the first component is representative of a third FM carrier wave.
Claim 41
Dependent Claim
37 words
A disc record as recited in claim 37 wherein said two FM carrier waves are modulated so as to convey audio information and wherein said third FM carrier wave is modulated so as to convey video information.
Claim 42
Independent Claim
76 words
A method for recording a disc record, comprising: providing a low frequency AC signal and a high frequency AC signal, each of constant amplitude; combining said AC signals to provide a composite signal; forming a spiral groove in a master substrate in accordance with said composite signal; and monotonically varying the amplitude of said low frequency AC signal without altering the amplitude of said high frequency AC signal while forming said groove in said substrate material.
Claim 43
Independent Claim
76 words
A method for recording a disc record, comprising: providing a low frequency AC signal and a high frequency AC signal, each of constant amplitude; combining said AC signals to provide a composite signal; forming a spiral groove in a master substrate in accordance with said composite signal; and monotonically varying the amplitude of said low frequency AC signal without altering the amplitude of said high frequency AC signal while forming said groove in said substrate material.
Claim 44
Dependent Claim
23 words
The method as recited in claim 39 further comprising the step of forming a replica of the groove pattern of the master substrate.
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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) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |