US3715445A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Musical instrument having dc-keying circuit
Assignee: Chicago Musical Instrument Co
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Filing: 1971-04-30
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Granted: 1973-02-06
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Expires: 1991-04-30
Abstract
Abstract A musical instrument, such as an electronic organ, includes normally constantly running tone-signal sources which are coupled by key-operated switches to a transducer for converting the tonesignals into audible sounds by means of a DC-keying potential. The waveform of the tone signal comprises pulses which are modulated in shape by the DC-keying circuit as follows: at the onset or attack of the tone, the amplitudes of successive pulses are unidirectionally increased and the duration of said successive pulses are simultaneously unidirectionally decreased from a predetermined duration or duty cycle to a substantially shorter duration or duty cycle, while the reverse takes place at the decay of the tone. There is no modulation of frequency. By this circuit, the harmonic content of the tone-signal is varied in such a manner as to electronically closely simulate certain voices as brass, in a particularly realistic manner.
Inventors
- 👤 A Kniepkamp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:42
CPC Classifications
G; G10; G10H; G10H1/00; G10H1/02; G10H1/06; G10H1/14
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
120 words
A musical instrument comprising: a. a series of tone-signal sources normally constantly in operation and having a wave form including a steep voltagechanging portion; b. means for converting tone-signals into audible sound; c. a source of DC-keying potential; d. a series of key-operated switches connected to said source of DC-keying potential; and e. a modulating DC-keying circuit means controlled by said keyoperated switches and connected between said tone-signal sources and said converting means for coupling said tone-signal sources to said converting means while also unidirectionally simultaneously modulating the duration and amplitude of each tone signal pulse by varying said DC-keying potential without altering the tone signal frequency, the modulation of duration being an inverse function of the modulation of amplitude.
Claim 2
Dependent Claim
120 words
A musical instrument comprising: a. a series of tone-signal sources normally constantly in operation and having a wave form including a steep voltagechanging portion; b. means for converting tone-signals into audible sound; c. a source of DC-keying potential; d. a series of key-operated switches connected to said source of DC-keying potential; and e. a modulating DC-keying circuit means controlled by said keyoperated switches and connected between said tone-signal sources and said converting means for coupling said tone-signal sources to said converting means while also unidirectionally simultaneously modulating the duration and amplitude of each tone signal pulse by varying said DC-keying potential without altering the tone signal frequency, the modulation of duration being an inverse function of the modulation of amplitude.
Claim 3
Dependent Claim
120 words
A musical instrument comprising: a. a series of tone-signal sources normally constantly in operation and having a wave form including a steep voltage-changing portion; b. means for converting tone-signals into audible sound; c. a source of DC-keying potential; d. a series of key-operated switches connected to said source of DC-keying potential; and e. a modulating DC-keying circuit means controlled by said key-operated switches and connected between said tone-signal sources and said converting means for coupling said tone-signal sources to said converting means while also unidirectionally simultaneously modulating the duration and amplitude of each tone signal pulse by varying said DC-keying potential without altering the tone signal frequency, the modulation of duration being an inverse function of the modulation of amplitude.
Claim 4
Dependent Claim
120 words
A musical instrument comprising: a. a series of tone-signal sources normally constantly in operation and having a wave form including a steep voltage-changing portion; b. means for converting tone-signals into audible sound; c. a source of DC-keying potential; d. a series of key-operated switches connected to said source of DC-keying potential; and e. a modulating DC-keying circuit means controlled by said key-operated switches and connected between said tone-signal sources and said converting means for coupling said tone-signal sources to said converting means while also unidirectionally simultaneously modulating the duration and amplitude of each tone signal pulse by varying said DC-keying potential without altering the tone signal frequency, the modulation of duration being an inverse function of the modulation of amplitude.
Claim 5
Dependent Claim
27 words
A musical instrument according to claim 1 including conductors which interconnect said tone-signal sources with said modulating means, said conductors having a capacitative coupling with each other.
Claim 6
Dependent Claim
35 words
A musical instrument according to claim 2 in which said conductors comprise a cable with said conductors disposed in proximity to each other whereby said capacitative coupling is established by the mutual capacitance between conductors.
Claim 7
Dependent Claim
73 words
A musical instrument according to claim 1 in which each of said modulating means includes: a. a transistor having a base, a collector coupled to said converting means, and an emitter connected to a voltage potential reference; b. one of said key-operated switches having a resistive coupling with said base and with said collector for applying the DC-keying potential thereto; and c. a capacitor coupling said base to one of said tone-signal sources.
Claim 8
Dependent Claim
40 words
A musical instrument according to claim 4 including isolation means by which said collector of each of a plurality of said modulating means are connected together as a collector bus, said collector bus having a coupling with said converting means.
Claim 9
Dependent Claim
37 words
A musical instrument according to claim 1 including means for each of said switches for controlling the rates of attack and decay, said controlling means respectively connecting each of said switches to each of said modulating means.
Claim 10
Dependent Claim
41 words
A musical instrument according to claim 6 in which said controlling means comprises: a. a capacitor connected to said modulating means; b. a charging circuit between the key-operated switch and said capacitor; and c a discharge circuit connected to said capacitor.
Claim 11
Dependent Claim
31 words
A musical instrument according to claim 7 in which said charging circuit has an impedance several times greater than that of said discharge circuit, whereby a brass instrument tone is simulated.
Claim 12
Dependent Claim
33 words
A musical instrument according to claim 1 including a tremolo oscillator connected to said source of DC-keying potential to cyclically vary the magnitude of said DC-keying potential by superimposing a tremolo signal thereon.
Claim 13
Dependent Claim
37 words
A musical instrument according to claim 9 having a selectively positionable voltage divider connected to said tremolo oscillator and to said source of DC-keying potential to select the ratio of the DC-keying potential and said tremolo signal.
Claim 14
Dependent Claim
25 words
A musical instrument according to claim 1 having a selectively positionable voltage divider connected with said source of DC-keying potential to determine said DC-kEying potential.
Claim 15
Dependent Claim
50 words
A musical instrument according to claim 11 having a selectively positionable volume control connected to said converting means, said volume control and said voltage divider having a mechanical connection with each other for joint operation, and so connected electrically that the dc-keying potential will be increased as volume is increased.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |