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US4122502A Expired / Lapsed US ⏱️ 0.0 years remaining

Playback system for a magnetic tape recorder

Assignee: Nakamichi Research Inc
•
Filing: 1977-03-03
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Granted: 1978-10-24
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Expires: 1997-03-03
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Abstract

Abstract This invention relates to a playback system for a magnetic tape recorder comprising an amplitude distortion corrector. It has an input versus output characteristic such that when the input level is less than the playback saturation level, which corresponds to the start of non-linear characteristics of the playback signal produced from a recorded signal at more than the recording saturation level due to a saturation of the magnetic tape, the output level is proportional to the input level. When the input level is more than the playback saturation level, the input verses output characteristics is complementary to the input versus output characteristic of the magnetic tape at corresponding signal levels. The playback system further comprises a high frequency emphasizer having an emphasizing circuit section having predetermined frequency characteristics disposed before the amplitude distortion corrector to emphasize predetermined frequencies in the playback signal so as to correct frequency dependent variations in the non-linear characteristics of the playback signal corresponding to a high level recorded signal which occurs due to saturation of the magnetic tape. The playback system further comprises a high frequency attenuator disposed after the amplitude distortion corrector and having frequency characteristic complementary to that of the high frequencies emphasizer so as to attenuate the frequency emphasized by the high frequency emphasizer.

Inventors

  • 👤 Kozo Kobayashi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 14:24
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/0007

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 220 words
A playback system for a magnetic tape recorder comprising a high frequency emphasizer means for receiving the playback signal having an emphasizing circuit section having predetermined frequency characteristics to emphasize predetermined frequencies in the playback signal; an amplitude distortion corrector receiving the output of said high frequency emphasizing means having an input versus output characteristic such that when the input level is less than the playback saturation signal level, which is the start of non-linear characteristics of the playback signal produced from a recorded signal at more than the recording saturation level due to saturation of the magnetic tape, the output level is proportional to the input level, and when the input level is more than the playback saturation level, the output level is complementary to the out level of the magnetic tape at corresponding signal levels above the recording saturation level for correcting the frequency dependent variations in the non-linear characteristics of the playback signal corresponding to a recorded signal of high level which occur due to saturation of the magnetic tape; and a high frequency attenuator receiving the output of said amplitude distortion corrector and having frequency characteristics complementary to that of said emphasizing circuit section of said high frequency emphasizer so as to attenuate the frequencies emphasized by said emphasizing circuit section of said high frequency emphasizer.
Claim 2
Dependent Claim 220 words
A playback system for a magnetic tape recorder comprising a high frequency emphasizer means for receiving the playback signal having an emphasizing circuit section having predetermined frequency characteristics to emphasize predetermined frequencies in the playback signal; an amplitude distortion corrector receiving the output of said high frequency emphasizing means having an input versus output characteristic such that when the input level is less than the playback saturation signal level, which is the start of non-linear characteristics of the playback signal produced from a recorded signal at more than the recording saturation level due to saturation of the magnetic tape, the output level is proportional to the input level, and when the input level is more than the playback saturation level, the output level is complementary to the out level of the magnetic tape at corresponding signal levels above the recording saturation level for correcting the frequency dependent variations in the non-linear characteristics of the playback signal corresponding to a recorded signal of high level which occur due to saturation of the magnetic tape; and a high frequency attenuator receiving the output of said amplitude distortion corrector and having frequency characteristics complementary to that of said emphasizing circuit section of said high frequency emphasizer so as to attenuate the frequencies emphasized by said emphasizing circuit section of said high frequency emphasizer.
Claim 3
Dependent Claim 125 words
A playback system for a magnetic tape recorder as set forth in claim 1, wherein said high frequency emphasizer means further comprises a further emphasizing circuit section having predetermined frequency characteristics to emphasize the playback signal so as to correct high frequency looses including the gap loss of the magnetic head, and a phase corrector disposed preliminary to said amplitude distortion corrector and having phase characteristics in which the phase shift of the playback signal due to the frequency characteristics of said emphasizing circuit section and said further emphasizing circuit section is corrected to provide a phase characteristic of the input signal to said amplitude distortion corrector to approximate the characteristic in which the phase shift is proportional to the frequency of the input signal.
Claim 4
Dependent Claim 39 words
A playback system for a magnetic tape recorder as set forth in claim 2, wherein said emphasizing circuit section and said further emphasizing circuit section of said high frequency emphasizer are connected before and after said phase corrector, respectively.
Claim 5
Dependent Claim 38 words
A playback system for a magnetic tape recorded as set forth in claim 2, wherein said emphasizing circuit section and said further emphasizing circuit section are connected directly to each other, and disposed preliminary to said phase corrector.

References Cited (Backward Citations)

US2868890A Cited
US3568174A Cited
US3927420A Cited
US4038692A Cited
DE2502980A1 Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1981-10-23 1982-04-24 1982-10-24 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1985-10-23 1986-04-24 1986-10-24 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1989-10-23 1990-04-24 1990-10-24 $7700.00 Window Closed / Lapsed

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