Patent US3733955A successfully refreshed from Google Patents.
US3733955A
Expired / Lapsed
US
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Music synthesizer keyboard circuit
Assignee: Venture Technologies Inc
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Filing: 1971-12-06
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Granted: 1973-05-22
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Expires: 1991-12-06
Abstract
Abstract A keyboard circuit for an electronic music generator, such as an electronic synthesizer. The circuit makes it possible to independently control the frequencies of two voltage controlled oscillators at the same time with a single resistance string by sensing a change in potential across the entire string when a second key is depressed and summing this potential with the first note potential. Gate and trigger signals are provided for the two notes, one being generated by an AC signal superimposed on the string.
Inventors
- 👤 F Reinagel
- 👤 E Zumchak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:38
CPC Classifications
G; G10; G10H; G10H5/00; G10H5/002; Y; Y10; Y10S; Y10S84/00; Y10S84/08
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
63 words
A keyboard circuit comprising a multiplicity of seriesconnected resistors, or a resistance string, means coupled to said string for supplying it with a constant current, a buss lead, a set of switches coupling said buss lead to spaced points along said string, a first note output coupled to said buss lead, and a second note output coupled to one end of said string.
Claim 2
Dependent Claim
63 words
A keyboard circuit comprising a multiplicity of seriesconnected resistors, or a resistance string, means coupled to said string for supplying it with a constant current, a buss lead, a set of switches coupling said buss lead to spaced points along said string, a first note output coupled to said buss lead, and a second note output coupled to one end of said string.
Claim 3
Dependent Claim
16 words
A circuit according to claim 1 wherein said string comprises a series of equal resistance elements.
Claim 4
Dependent Claim
20 words
A circuit according to claim 1 wherein said buss lead is coupled to said first note output by a buffer.
Claim 5
Dependent Claim
16 words
A circuit according to claim 3 wherein said buffer comprises a high input impedance sample-hold circuit.
Claim 6
Dependent Claim
26 words
A circuit according to claim 1 wherein said constant current means comprises an operational amplifier, said string being coupled in the feedback circuit of said amplifier.
Claim 7
Dependent Claim
21 words
A circuit according to claim 5 wherein said second note output os coupled to the low potential end of said string.
Claim 8
Dependent Claim
49 words
A circuit according to claim 1 including a difference circuit having its output coupled to said second note output, a first input of said difference circuit being coupled to said one end of said string and a second input of said difference circuit being coupled to said buss lead.
Claim 9
Dependent Claim
14 words
A circuit according to claim 7 wherein said difference circuit comprises a difference amplifier.
Claim 10
Dependent Claim
64 words
A keyboard circuit comprising a resistance string, a constant current source coupled to said string, a buss lead, a set of keyboard switches coupling said buss lead to spaced points along said string, a DC output coupled to said buss lead, means coupled to said string for superimposing an AC signal on said string, and a transient control output coupled to said buss lead.
Claim 11
Dependent Claim
64 words
A keyboard circuit comprising a resistance string, a constant current source coupled to said string, a buss lead, a set of keyboard switches coupling said buss lead to spaced points along said string, a DC output coupled to said buss lead, means coupled to said string for superimposing an AC signal on said string, and a transient control output coupled to said buss lead.
Claim 12
Dependent Claim
15 words
A circuit according to claim 9 wherein said transient control output comprises a gate output.
Claim 13
Dependent Claim
15 words
A circuit according to claim 9 wherein said transient control output comprises a trigger output.
Claim 14
Dependent Claim
21 words
A circuit according to claim 9 including an AC amplifier and demodulator coupling said bus lead to said transient control output.
Claim 15
Dependent Claim
92 words
A keyboard circuit comprising a resistance string, a constant current source coupled to aid string, a buss lead, a set of keyboard switches coupling said buss lead to spaced points along said string, a buffer coupled to said buss lead, a first note output coupled to said buffer, a difference amplifier having first and second inputs, said first input being coupled to the output of said buffer and said second input being coupled to one end of said string, and a second note output coupled to the output of said difference amplifier.
Claim 16
Dependent Claim
92 words
A keyboard circuit comprising a resistance string, a constant current source coupled to aid string, a buss lead, a set of keyboard switches coupling said buss lead to spaced points along said string, a buffer coupled to said buss lead, a first note output coupled to said buffer, a difference amplifier having first and second inputs, said first input being coupled to the output of said buffer and said second input being coupled to one end of said string, and a second note output coupled to the output of said difference amplifier.
Claim 17
Dependent Claim
18 words
A circuit according to claim 13 including a Glissando circuit coupling said buffer to said first note output.
Claim 18
Dependent Claim
18 words
A circuit according to claim 13 including a first note transient control output coupled to said buss lead.
Claim 19
Dependent Claim
36 words
A circuit according to claim 15 including an audio frequency oscillator coupled to said string, said first transient control output being coupled to said buss lead through an AC amplifier, a detector and a threshold device.
Claim 20
Dependent Claim
20 words
A circuit according to claim 15 including a second note transient control output coupled to said end of said string.
Claim 21
Dependent Claim
23 words
A circuit according to claim 17 including a voltage comparator coupling said second note transient control output to said end of said string.
Claim 22
Dependent Claim
24 words
A circuit according to claim 13 and further including an electronic synthesizer having a keyboard with a separate key for each of said switches.
Claim 23
Dependent Claim
16 words
Apparatus according to claiM 19 wherein said synthesizer has a four octave keyboard with 49 keys.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |