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US3683515A Expired / Lapsed US ⏱️ 0.0 years remaining

Cross-talk elimination system for an instructional tape recorder

Assignee: Panasonic Holdings Corp
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Filing: 1970-10-02
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Granted: 1972-08-15
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Expires: 1990-10-02
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Abstract

Abstract A cross-talk elimination system for an instructional tape recorder comprises a recording and a reproducing means for recording and reproducing an instructional tape which has intermittently recorded thereon an instructional program and an oral response of a learner made to said instructional program. Said cross-talk elimination system has an electric network for reducing a leakage signal coupled to a magnetic reproducing head from a magnetic recording head either magnetically or electrostatically. Said electrical network produces an electrical signal having the same amplitude and phase characteristics as said leakage signal. Said electrical signal is coupled differentially to said leakage signal for reducing said leakage signal.

Inventors

  • 👤 Masahiro Kosaka

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 14:20
CPC Classifications
G; G09; G09B; G09B5/00; G09B5/04; G11; G11B; G11B5/00

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 258 words
A cross-talk elimination system for an instructional tape recorder, comprising, in combination, a magnetic tape having first and second recording tracks thereon; a program channel having a first magnetic recording/reproducing head and a first recording/reproducing circuit for recording/reproducing an instructional program onto said first recording track of said magnetic tape; a student channel having a second magnetic recording/reproducing head and a second recording/reproducing circuit for recording/reproducing a learner''s oral sigNal onto said second recording track of said magnetic tape; a coupling network means for coupling signals from said program channel with signals from said student channel; a monitor amplifier means for amplifying a signal from said coupling network means and for driving a headphone or a loudspeaker in order to make it possible for said learner to hear said instructional program and said learner''s signal simultaneously; an electrical network means connected to said second magnetic recording/reproducing head for producing a compensating electric signal having the same amplitude and phase as a leakage signal appear across a winding of said first magnetic recording/reproducing head at a reproducing mode when said second magnetic recording/reproducing head is at a recording mode; and a mixing network means connected between said electrical network means and said first magnetic recording/reproducing head for combining differentially said compensating electric signal with an electric signal appearing across a winding of said first magnetic recording/reproducing head in order to reduce the amplitude of said leakage signal when said first magnetic recording/reproducing head and said second magnetic recording/reproducing head are at a reproducing mode and a recording mode, respectively.
Claim 2
Dependent Claim 258 words
A cross-talk elimination system for an instructional tape recorder, comprising, in combination, a magnetic tape having first and second recording tracks thereon; a program channel having a first magnetic recording/reproducing head and a first recording/reproducing circuit for recording/reproducing an instructional program onto said first recording track of said magnetic tape; a student channel having a second magnetic recording/reproducing head and a second recording/reproducing circuit for recording/reproducing a learner''s oral sigNal onto said second recording track of said magnetic tape; a coupling network means for coupling signals from said program channel with signals from said student channel; a monitor amplifier means for amplifying a signal from said coupling network means and for driving a headphone or a loudspeaker in order to make it possible for said learner to hear said instructional program and said learner''s signal simultaneously; an electrical network means connected to said second magnetic recording/reproducing head for producing a compensating electric signal having the same amplitude and phase as a leakage signal appear across a winding of said first magnetic recording/reproducing head at a reproducing mode when said second magnetic recording/reproducing head is at a recording mode; and a mixing network means connected between said electrical network means and said first magnetic recording/reproducing head for combining differentially said compensating electric signal with an electric signal appearing across a winding of said first magnetic recording/reproducing head in order to reduce the amplitude of said leakage signal when said first magnetic recording/reproducing head and said second magnetic recording/reproducing head are at a reproducing mode and a recording mode, respectively.
Claim 3
Dependent Claim 75 words
A cross-talk elimination system for an instructional tape recorder as claimed in claim 1, wherein said electrical network means and said mixing network means are combined into one circuit which comprises a first resistor inserted between a return terminal of said second magnetic recording/reproducing head and ground, a second resistor inserted between a return terminal of said first magnetic recording/reproducing head and ground, and a capacitor connected between said first resistor and said second resistor.
Claim 4
Dependent Claim 55 words
A cross-talk elimination system for an instructional tape recorder as claimed in claim 1, wherein said coupling network means has electrical switches which disconnect an electrical signal from said student channel to said monitor amplifier means when said program channel and said student channel are in a reproducing operation and in a recording operation, respectively.
Claim 5
Dependent Claim 61 words
A cross-talk elimination system for an instructional tape recorder as claimed in claim 1, wherein an inductance is inserted between a return terminal of said first magnetic recording/reproducing head and ground, said inductance generating said compensating electric signal when an electric current proportional to a recording current of said second magnetic recording/reproducing head at a recording mode flows through said inductance.
Claim 6
Dependent Claim 77 words
A cross-talk elimination system for an instructional tape recorder as claimed in claim 4, wherein said electric current proportional to a recording current is derived by a resistance network consisting of two resistors, one of which is connected between a return terminal of said second magnetic recording/reproducing head and ground, and the other of which is connected between said return terminal of said second magnetic recording/reproducing head and a return terminal of said first magnetic recording/reproducing head.
Claim 7
Dependent Claim 28 words
A cross-talk elimination system for an instructional tape recorder as claimed in claim 4, wherein said inductance is provided by a winding of said first magnetic recording/reproducing head.
Claim 8
Dependent Claim 39 words
A cross-talk elimination system for an instructional tape recorder as claimed in claim 1, wherein an inductance is inserted between a return terminal of said second magnetic recording/reproducing head and ground in order to obtain said compensating electric signal.
Claim 9
Dependent Claim 51 words
A cross-talk elimination system for an instructional tape recorder as claimed in claim 7, wherein said inductance is provided by a winding of said second magnetic recording/reproducing head in order to obtain said compensating electric signal, said compensating electric signal being connected to said mixing network means through a resistance network.
Claim 10
Dependent Claim 25 words
A cross-talk elimination system for an instructional Tape recorder as claimed in claim 8, wherein said resistance network consists essentially of at least two resistors.

References Cited (Backward Citations)

US2713676A Cited
US2727096A Cited
FR1116295A Cited
US2986608A Cited
US3342952A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-08-15 1976-02-14 1976-08-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-08-15 1980-02-14 1980-08-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-08-15 1984-02-14 1984-08-15 $7700.00 Window Closed / Lapsed

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