Patent US4247875A successfully refreshed from Google Patents.
US4247875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuitry for adjustment of biasing current for recording sound by two-head type tape-recorder
Assignee: Onkyo Corp
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Filing: 1979-04-12
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Granted: 1981-01-27
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Expires: 1999-04-12
Abstract
Abstract A circuitry has a calibration signal generator, a higher frequency range output level adjusting circuit and a recording bias current adjusting variable resistor. The signal generator continually alternately gives output two kinds of calibration signals of lower and higher frequencies. The higher range adjusting circuit is operatively connected with the variable resistor, and adjusts output sound level, as indicated at an indicator, only of the higher frequency signal of the two calibration signals.
Inventors
- 👤 Satoshi Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:43
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/02; G11B5/027; G11B5/03
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
188 words
Recording bias current adjusting circuitry adapted for use in a two-head type tape recorder having an eraser head and a recording/reproduction head (7) comprising; a calibration signal generator (1) adapted to alternately and continuously give to a recording input stage two kinds of calibration signals of higher and lower frequencies but of the same input level, a variable resistor (12) for adjusting intensity of a recording bias current, an indicator (15) for indicating output levels of reproduced signals, an output level adjusting circuit (13) adapted to adjust only higher-frequency reproduction output levels out of various-frequency reproduction output levels indicated at the indicator (15), and said variable resistor (12) being operatively connected to the output level adjusting circuit (13) for adjusting the output level adjusting circuit (13) and adapted to be settable to a resistance value to provide an optimal intensity of the recording bias current to realize a flat frequency characteristic when the output level adjusting circuit (13) is adjusted to cause the reproduced output level of the higher-frequency calibration signal to coincide with the reproduced output level of the lower-frequency calibration signal shown at the indicator (15).
Claim 2
Dependent Claim
188 words
Recording bias current adjusting circuitry adapted for use in a two-head type tape recorder having an eraser head and a recording/reproduction head (7) comprising; a calibration signal generator (1) adapted to alternately and continuously give to a recording input stage two kinds of calibration signals of higher and lower frequencies but of the same input level, a variable resistor (12) for adjusting intensity of a recording bias current, an indicator (15) for indicating output levels of reproduced signals, an output level adjusting circuit (13) adapted to adjust only higher-frequency reproduction output levels out of various-frequency reproduction output levels indicated at the indicator (15), and said variable resistor (12) being operatively connected to the output level adjusting circuit (13) for adjusting the output level adjusting circuit (13) and adapted to be settable to a resistance value to provide an optimal intensity of the recording bias current to realize a flat frequency characteristic when the output level adjusting circuit (13) is adjusted to cause the reproduced output level of the higher-frequency calibration signal to coincide with the reproduced output level of the lower-frequency calibration signal shown at the indicator (15).
Claim 3
Dependent Claim
59 words
Circuitry as defined in claim 1, wherein said calibration signal generator (1) comprises a lower-frequency calibration signal generator (2), a higher-frequency calibration signal generator (3), a square-wave signal generator (4), said three signal generator (2,3,4) being arranged parallel to one another, and a switching circuit (5) commonly inserted in output lines of the three signal generators (2, 3, 4).
Claim 4
Dependent Claim
61 words
Circuitry as defined in claim 2, wherein said higher-frequency range output level adjusting circuit (13) comprises a low pass filter (16) and high pass filter (17) in parallel connection, a fixed resistor (19) inserted in an output line of the low pass filter (16), and a further variable resistor (18) inserted in an output line of the high pass filter (17).
Claim 5
Dependent Claim
72 words
Circuitry as defined in claim 3, wherein said two variable resistors (12, 18) are operatively connected such that variation in reproduced output level of a higher-frequency range signal indicated at the indicator (15) upon manipulation of the further variable resistor (18) substantially corresponds to variation in reproduced output level of the higher-frequency range signal resulting from variation in the recording bias current caused by the interlocked operation of the variable resistor (12).
Claim 6
Dependent Claim
33 words
Circuitry as defined in claim 4, wherein said lower and higher-frequency calibration signal generators (2,3) are adapted to give sinusoidal calibration signals substantially of the frequencies of 400 Hz and 10 kHz, respectively.
Claim 7
Dependent Claim
35 words
Circuitry as defined in claim 5, wherein said square-wave signal generator (4) and the switching circuit (5) are adapted to give the higher-frequency calibration signal for a longer duration than the lower frequency calibration signal.
Claim 8
Dependent Claim
38 words
Circuitry as defined in claim 6, wherein said square-wave signal generator (4) and the switching circuit (5) are adapted to give the lower-frequency calibration signal substantially for one second and the higher-frequency calibration signal substantially for three seconds.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |