US3683131A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic tape recording circuit
Assignee: Bell and Howell Co
•
Filing: 1965-06-28
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Granted: 1972-08-08
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Expires: 1985-06-28
Abstract
Abstract There is described a recording amplifier circuit for a magnetic recorder providing a very low output impedance in series with the winding on the magnetic recording head. The low output impedance is achieved by negative feedback, preferably derived from the voltage across the drive coil or derived from a separate coil on the magnetic head wound concentrically with the drive coil.
Inventors
- 👤 Wayne K Hodder
- 👤 Lewis B Browder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:10
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/56; G; G11; G11B; G11B5/00; G11B5/02; G11B5/027; H03F3/00; H03F3/181; H03F3/183
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
112 words
Apparatus for recording a signal on magnetic tape comprising a recording head including a magnetic core having a recording gap and a drive coil of low resistance wound on the core, a source of signals to be recorded, and a drive amplifier coupling the source to the drive coil, the drive amplifier providing a two-terminal output impedance connected directly across the drive coil of the recording head, the total resistance of the output impedance of the amplifier, the connection between the head coil and the amplifier, and the resistance of the coil being small compared to the inductive reactance of the head coil over the operating frequency range of the recorded signal.
Claim 2
Dependent Claim
112 words
Apparatus for recording a signal on magnetic tape comprising a recording head including a magnetic core having a recording gap and a drive coil of low resistance wound on the core, a source of signals to be recorded, and a drive amplifier coupling the source to the drive coil, the drive amplifier providing a two-terminal output impedance connected directly across the drive coil of the recording head, the total resistance of the output impedance of the amplifier, the connection between the head coil and the amplifier, and the resistance of the coil being small compared to the inductive reactance of the head coil over the operating frequency range of the recorded signal.
Claim 3
Dependent Claim
25 words
Apparatus as defined in claim 1 wherein the output impedance of the drive amplifier presents less than one ohm in series with the drive coil.
Claim 4
Dependent Claim
28 words
Apparatus as defined in claim 1 wherein the small output impedance is provided by a negative feedback circuit connected across the coil and coupled to the amplifier input.
Claim 5
Dependent Claim
40 words
Apparatus as defined in claim 1 wherein the recording head includes a second coil wound on the core, the small output impedance being provided by a negative feedback circuit connected across the second coil and coupled to the amplifier input.
Claim 6
Dependent Claim
17 words
Apparatus as defined in claim 4 wherein the second coil is wound concentriCally with the drive coil.
Claim 7
Dependent Claim
19 words
Apparatus as defined in claim 4 wherein the second coil is wound on the core adjacent the recording gap.
Claim 8
Dependent Claim
15 words
Apparatus as defined in claim 4 wherein the negative feedback circuit includes an integrating network.
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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) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |