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 Title: |
US3873782:
CAPACITIVE PROTECTION COUPLING ELEMENT FOR STYLUS ELECTRODE DISCHARGE
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Palmer, Richard Claxton; Blawenburg, NJ
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| Assignee: |
RCA Corporation, New York, NY
other patents from RCA CORPORATION (466175) (approx. 7,929)
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| Published / Filed: |
1975-03-25
/ 1973-02-08
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| Application Number: |
US1973000330877
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| IPC Code: |
Advanced:
G11B 3/46;
G11B 9/06;
G11B 9/07;
H04N 5/92;
Core:
G11B 3/00;
G11B 9/00;
more...
IPC-7:
G11B 3/44;
G11B 9/06;
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| U.S. Class: |
Current:
369/126;
369/129;
369/244.1;
369/256;
G9B/003.078;
G9B/009.023;
Original:
179/100.1B;
179/100.41G;
178/006.6A;
178/006.6TP;
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| Field of Search: |
179/100.4 M,100.1 B,100.41 G,100.41 P,100.41 B
178/6.6 TP
274/038
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| Priority Number: |
| 1973-02-08 |
US1973000330877 |
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| Abstract: |
To protect a playback stylus against arcing, a relatively small value capacitance is provided in series circuit relationship with the stylus electrode. This capacitance limits damaging charge flow through the stylus electrode from the record medium surface.
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| Attorney, Agent or Firm: |
Whitacre, Eugene M. ;
Hayes, J. B. ;
Meagher, William H. ;
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| Primary / Asst. Examiners: |
Moffitt, James W.; Moore, David K.
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| INPADOC Legal Status: |
None
Family Legal Status Report
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| Family: |
Show 20 known family members
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First Claim:
Show all 4 claims |
What is claimed is:
1. A playback system for use with a video disc record having geometrical variations in a spiral groove on a major surface of the disc record, said surface including a layer of conductive material covering a dielectric substrate, with a dielectric coating overlying said conductive layer; said system comprising: a rotatable turntable of conductive material direct current conductively connected to a point of reference potential; a tracking stylus supported for cooperative engagement with said record groove when said record is in a playback position, with said turntable in supporting engagement with a surface of said record opposed to said major surface; said tracking stylus including an electrode presenting a conductive surface which cooperates with said conductive layer and dielectric coating of said disc record to form a varying capacitance as said record is rotated during playback; means for normally precluding the charging of capacitance exhibited between said conductive layer and the conductive material of said turntable, said charging precluding means comprising conductive means for providing a direct current conductive connection between said conductive layer of said record and said point of reference potential; said charging precluding means being ineffective, however, in precluding the accumulation of charge on any region of said conductive layer undesirably subject to DC isolation from said conductive means; and means for developing electrical signal variations representative of the variations of said varying capacitance, said signal variation developing means including circuit means, separate from said varying capacitance and said conductive means, for establishing an electrical signal path between said stylus electrode and said point of reference potential; and wherein said separate circuit means includes means for limiting the flow of discharging current through said stylus electrode in the event of stylus engagement with a groove surface overlying any region of said conductive layer subject to said DC isolation from said conductive means, said limiting means including a capacitor interposed in said signal path in such manner as to effect DC isolation of said stylus electrode from said point of reference potential.
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| Background / Summary: |
Show background / summary
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 3 U.S. patent(s) that reference this one
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