US4041832A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tuning aids
Assignee: Individual
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Filing: 1975-11-25
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Granted: 1977-08-16
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Expires: 1995-11-25
Abstract
Abstract A musical instrument tuning aid includes a stable source of reference signals. Those signals are divided by a selected amount to produce a given tone signal. A note produced by an instrument under test or measurement is detected and used to develop a corresponding sensed signal. Variations in phase between successive time increments of the sensed signal desirably are averaged so as to produce a measurement signal. The sensed or measurement signal is compared in frequency with the tone signal for the purpose of producing an indication signal. In response to that comparison, a display indicates whether the instrument is sharp, flat, or on-tune. A signal presence detector may be included for the purpose of disabling the display in the absence of a signal to be tested. Also preferably included is an arrangement for causing the on-tune display to flicker at a rate representative of the nearness to an exact match.
Inventors
- 👤 Douglas M. Risch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:17
CPC Classifications
G; G10; G10G; G10G7/00; G10G7/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
199 words
A tuning aid comprising: a stable source of reference signal having a selectable frequency to produce a given digital tone signal; means for sensing a note developed by an instrument and developing a corresponding digital measurement signal; means for comparing said tone and measurement signals to produce indicating signals representing respectively the one present of the conditions of sharp, flat or on-tune of said measurement signal relative to said tone signal, said comparing means having a phase difference detector responsive to said tone and measurement signals for producing a difference signal and a single phase shift detector responsive to said tone and measurement signals and also to said difference signal for producing a first indication signal representing said sharp condition, a second indication signal representing said flat condition and a combination of said first and second signals representing said on-tune condition; and means responsive to said indicating signals for displaying the respective one of said conditions indicated, said responsive means including first, second and third display elements individually energized in response to respective different ones of said indicating signals and each displaying a single, fixed, stationary and continuous indication of the respective one of the conditions to be indicated.
Claim 2
Dependent Claim
199 words
A tuning aid comprising: a stable source of reference signal having a selectable frequency to produce a given digital tone signal; means for sensing a note developed by an instrument and developing a corresponding digital measurement signal; means for comparing said tone and measurement signals to produce indicating signals representing respectively the one present of the conditions of sharp, flat or on-tune of said measurement signal relative to said tone signal, said comparing means having a phase difference detector responsive to said tone and measurement signals for producing a difference signal and a single phase shift detector responsive to said tone and measurement signals and also to said difference signal for producing a first indication signal representing said sharp condition, a second indication signal representing said flat condition and a combination of said first and second signals representing said on-tune condition; and means responsive to said indicating signals for displaying the respective one of said conditions indicated, said responsive means including first, second and third display elements individually energized in response to respective different ones of said indicating signals and each displaying a single, fixed, stationary and continuous indication of the respective one of the conditions to be indicated.
Claim 3
Dependent Claim
41 words
A tuning aid as defined in claim 1 which further includes means for effecting flicker of said third display element at a rate representative of the degree of nearness to an exact match between said tone signal and said measurement signal.
Claim 4
Dependent Claim
49 words
A tuning aid as defined in claim 2 in which said flicker means includes a time-charge circuit for energizing said third display element in said responsive means and which further includes a generator of pulses to reset said time-charge circuit at a rate proportional to said degree of nearness.
Claim 5
Dependent Claim
75 words
A tuning aid as defined in claim 1 in which said phase shift detector directly develops said first and second indicating signals acted upon by said responsive means for displaying the present one of said sharp or flat conditions, and in which said combination of said first and second signals constitutes another indicating signal acted upon by said responsive means for displaying nearness to an exact match between said tone signal and said measurement signal.
Claim 6
Dependent Claim
77 words
A tuning aid as defined in claim 1 which further includes means coupled to said sensing means and responsive to said note sensed for disabling said responsive means in the absence of meaningful existence of said note sensed, in which said phase shift detector normally produces an indicating signal representing said flat condition in the absence of said measurement signal, and in which said disabling means effectively deactivates display by said responsive means of such flat condition.
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) | 1980-08-15 | 1981-02-14 | 1981-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-15 | 1985-02-14 | 1985-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-15 | 1989-02-14 | 1989-08-16 | $7700.00 | Window Closed / Lapsed |