US3973223A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency-deviation method and apparatus
Assignee: Nippon Gakki Co Ltd
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Filing: 1975-05-05
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Granted: 1976-08-03
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Expires: 1995-05-05
Abstract
Abstract A carrier wave having a sub-audible frequency is modulated in amplitude by a modulating wave of a tone signal having an audible frequency, which produces a resultant modulated output signal having first and second side band components respectively deviated above and below the tone signal frequency by a deviation amount equal to the carrier frequency. The frequency of the carrier wave is much lower than that of the modulating wave. This frequency deviation technique is utilized to provide a tremolo effect or a chorus effect in an electronic musical instrument, wherein the frequency-deviated signal is admixed with the original non-deviated signal.
Inventors
- 👤 Yasuji Uchiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:25
CPC Classifications
G; G10; G10H; G10H1/00; G10H1/02; G10H1/04; G10H1/043
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
188 words
In a technique for producing tremolo effects with an electronic musical instrument, an improved frequency-deviation method for producing musical tones that are shifted in frequency by an amount Δf both above and below a nominal tone frequency f, said method comprising the steps of: a. generating a modulating signal of said frequency f; b. generating a carrier signal of a frequency Δf, said frequency Δf being lower than said frequency f; and c. amplitude modulating said lower frequency carrier signal with said higher frequency modulating signal to produce a resultant signal which is the product of said carrier signal and said modulating signal and is of the form A (1 + MCOS wt) (COSΔwt), A and M being constants, w being equal to 2πf and Δw being equal to 2πΔf, and which has a frequency spectrum consisting of Δf, f-Δf, and f + Δf in order of increasing frequency; and d. removing the carrier frequency component Δf by passing said resultant signal through a low-pass filter, whereby a modulated output signal is produced having only the frequency component f - Δf and the frequency component f + Δf.
Claim 2
Dependent Claim
188 words
In a technique for producing tremolo effects with an electronic musical instrument, an improved frequency-deviation method for producing musical tones that are shifted in frequency by an amount Δf both above and below a nominal tone frequency f, said method comprising the steps of: a. generating a modulating signal of said frequency f; b. generating a carrier signal of a frequency Δf, said frequency Δf being lower than said frequency f; and c. amplitude modulating said lower frequency carrier signal with said higher frequency modulating signal to produce a resultant signal which is the product of said carrier signal and said modulating signal and is of the form A (1 + MCOS wt) (COSΔwt), A and M being constants, w being equal to 2πf and Δw being equal to 2πΔf, and which has a frequency spectrum consisting of Δf, f-Δf, and f + Δf in order of increasing frequency; and d. removing the carrier frequency component Δf by passing said resultant signal through a low-pass filter, whereby a modulated output signal is produced having only the frequency component f - Δf and the frequency component f + Δf.
Claim 3
Dependent Claim
132 words
A frequency-deviation apparatus comprising: phase separator means for receiving a signal and for supplying two modulating signals mutually having a 90° phase difference therefrom; an ultra-low-frequency oscillator means for generating two carrier signals to be modulated mutually having a 90° phase difference and having a frequency Δf which is much lower than that of said modulating signals; two amplitude modulator means for receiving as inputs selected combinations of the modulating signals and carrier signals to be modulated to produce respective output signals each of a frequency deviated from the frequency of the corresponding modulating signal by an increment ± Δ f of an absolute value equal to the frequency of the corresponding carrier signal being produced by mixing the outputs of the two amplitude modulators, and means for mixing said output signals.
Claim 4
Dependent Claim
132 words
A frequency-deviation apparatus comprising: phase separator means for receiving a signal and for supplying two modulating signals mutually having a 90° phase difference therefrom; an ultra-low-frequency oscillator means for generating two carrier signals to be modulated mutually having a 90° phase difference and having a frequency Δf which is much lower than that of said modulating signals; two amplitude modulator means for receiving as inputs selected combinations of the modulating signals and carrier signals to be modulated to produce respective output signals each of a frequency deviated from the frequency of the corresponding modulating signal by an increment ± Δ f of an absolute value equal to the frequency of the corresponding carrier signal being produced by mixing the outputs of the two amplitude modulators, and means for mixing said output signals.
References Cited (Backward Citations)
US3493669A
Cited
US3510567A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |