US3614288A - Monophonic electronic musical instrument with variable filter - Google Patents

Monophonic electronic musical instrument with variable filter Download PDF

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Publication number
US3614288A
US3614288A US842547A US3614288DA US3614288A US 3614288 A US3614288 A US 3614288A US 842547 A US842547 A US 842547A US 3614288D A US3614288D A US 3614288DA US 3614288 A US3614288 A US 3614288A
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United States
Prior art keywords
voltage
frequency
controlling
tone
musical instrument
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Expired - Lifetime
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US842547A
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English (en)
Inventor
Takehisa Amano
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Gakki Co Ltd
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Nippon Gakki Co Ltd
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G5/00—Tone control or bandwidth control in amplifiers
    • H03G5/16—Automatic control
    • H03G5/18—Automatic control in untuned amplifiers
    • H03G5/22—Automatic control in untuned amplifiers having semiconductor devices
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H1/00—Details of electrophonic musical instruments
    • G10H1/02—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos
    • G10H1/06—Circuits for establishing the harmonic content of tones, or other arrangements for changing the tone colour
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H5/00—Instruments in which the tones are generated by means of electronic generators
    • G10H5/002—Instruments using voltage controlled oscillators and amplifiers or voltage controlled oscillators and filters, e.g. Synthesisers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G5/00—Tone control or bandwidth control in amplifiers
    • H03G5/02—Manually-operated control
    • H03G5/04—Manually-operated control in untuned amplifiers
    • H03G5/10—Manually-operated control in untuned amplifiers having semiconductor devices

Definitions

  • the present invention relates to a monophonic electronic musical instrument having a filter whose frequency characteristic is shifted in accordance with the pitch of a tone signal from a tone generator.
  • a monophonic electronic musical instrument normallyemployed a filter whose circuit constant is fixed as shown in FIG. 1.
  • the presentinvention is intended to eliminate the abovementioned defects and to provide a musical instrument wherein a variable filter is provided between a tone generator and an output amplifier so that the output characteristics thereof may be appropriately varied in accordance with the tone pitch.
  • the object of the present invention is to provide a monophonic electronic musical instrument comprising means for producing a controlling DC voltage in accordance with the operation of relative keys and a variable filter whose frequency characteristic is changed in accordance with said controlling voltage, said output characteristics of the filter being variable following the pitch variation of the tone signal so as to prevent the distortion of tone color and volume when the tone pitch changes.
  • FIG.! shows a fixed filter used in an exampleof a conventional circuit
  • FIG. 2 is a block diagram showing an embodiment of the monophonic electronic musical instrument according to the present invention.
  • FIG. 3 shows an example of a controlling voltage circuit employed in the keyboard circuit of FIG. 2;
  • FIG. 4 shows an exemplified circuit of a variable filter of the present invention
  • FIG. 5 is a circuit diagram showing an actual example of the main portion of the block diagram given in FIG. 2;
  • FIG. 6 is a characteristic curve showing the relation between the gate voltage Vgs and the drain-source resistance Rds of the field effect transistor used in the variable filter in FIG. 5;
  • FIG. 7 shows the frequency characteristics of the variable filter in FIG. 5
  • FIG. 8 is ablock diagram showing another embodiment of the present invention.
  • FIG. 9 is a circuit diagram showing an actual example of the frequency-to-voltage converter in FIG. 8; and- FIG. 10 is a characteristic curve showing the relation between the frequency f and the output DC voltage V, of the frequency-to-voltage converter of FIG. 9. v
  • l is a keyboard circuit
  • 2 is a tone generator
  • 3 is a filter
  • 5 is aspeaker.
  • the keyboard circuit 1 has two switches for each key. One of these switches is to control the frequency of the tone generator in relation .to the key operated and the other is, as shown by way of an example in FIG. 3, is to produce controlling DC voltage for the variable filter 3 when the key is depressed.
  • K,, K,, K,,---, K represent transfer-contact switches each of which is actuated by the corresponding key.
  • Resistors R R,, R,, R are connected in series as illustrated. The point at which the related resistors are joined is connected to the normally open contact of the related switch. Therefore, when a desired key is depressed, only the switch that is connected to the key is actuated and thus the divided DC voltage at the junctions of the related resistorsis presented at a terminal T,.
  • the values of resistors R R,, R,,--, R, are appropriately determined based on the provision of the frequency characteristics of the filter 3.
  • FIG. 4 shows an example of a variable filter employed in the musical instrument of the present invention, which is of a lowpass type consisting of a capacitor C and a field effect transistor used as a variable resistor.
  • BP is a terminal connected to a biasing power source and VR is a variable resistor for regulating the FET bias, which is provided when necessary.
  • FIG. 5 shows an actual example of the above-mentioned embodiment having a three octave range of the keyboard from C;( I31 Hz.) to C,( 1047 Hz.).
  • Numeral 1 indicates a keyboard circuit
  • 3 represents a variable filter
  • the rest represents a tone generator consisting of a variable frequency oscillator 20, two stages of the frequency dividers 21 and 22, a driver 23 and a keyer 24.
  • the keyboard circuit includes two tapped resistors, the left one providing DC voltage for controlling the FET in the filter 3 and the right. one providing another DC voltage source for controlling the FET's and in turn the oscillation frequency of the oscillator 20.
  • the oscillation frequency is determined in the range of 523 Hz. through 4l86 Hz.
  • the divider 21 produces a half of the frequency derived from the oscillator 20.
  • the divider 22 produces a further half of the frequency derived from the-divider 21.
  • The'signals from the oscillator 20 and the dividers 21 and 22 are mixed and supplied to the keyer 24, which nonnally prevents the signal from passing to the filter but temporarily permits the signal to pass to the filter when a drive signal is supplied from a driver 23.
  • the driver 23 receives an AC signal from the oscillator through capacitors, the right-hand resistors and a key switch in the key board circuit I, amplifies the AC signal, rectifies the AC signal into DC signal, and amplifies the DC signal to produce the drive signal.
  • the oscillator starts to oscillate and the keyer starts to conduct, while the corresponding DC voltage is derived from the left-hand resistors in the keyboard circuit and is supplied to the filter to control its cutoff frequency.
  • the drainsource resistance of the FET in the filter varies in accordance with the gate voltage Vgs supplied from the keyboard circuit, as shown in FIG. 6.
  • the gate voltage when the key of C, note (131 Hz.) is depressed, the gate voltage is 2.1 volts, the resistance becomes 4 kilohms and the cutoff frequency of the filter is set at 200 Hz.; when the key of C, note (262 Hz.) is depressed, the gate voltage is l.7 volts, theFET resistance 2 kilohms and the cutoff frequency 400 Hz.; when the key of C, note (523 Hz.) is depressed, the gate voltage is I.l volts, the FET resistance I kilohm and the cutoff frequency 800 "2.; and when the key of C note 1047 Hz.) is depressed, the gate voltage is 0.1 volt, the FET resistance 0.5 kilohms and the cutoff frequency 1600 2.
  • FIG. 7 shows the variation of the filter characteristic as mentioned above.
  • FIG. 8 illustrates another embodiment of the present invention, in which the modification resides in the point that, the controlling voltage is supplied to the filter 3 from the output side of a frequency-to-voltage converter 6 which is to produce the output DC signal whose voltage is dependent on the frequency of the tone generator signal.
  • a frequency-to-voltage converter 6 which is to produce the output DC signal whose voltage is dependent on the frequency of the tone generator signal.
  • FIG. 9 One example of the converter .circuit is shown in FIG. 9, with the frequency-tovoltage-relation being asshown by the curvein FIG. 10.
  • the output signal of the oscillator (as in FIG. of the frequency f is supplied to the input terminal T of the converter and a DC voltage V, determined by the FIG. curve is taken out at the terminal T which in turn is connected to the gate of the FET of the variable filter 3 of the same construction as shown in FIG.
  • the frequency-to-voltage converter may be of another type such as a discriminator used in a conventional FM broadcasting receiver set.
  • a monophonic electronic musical instrument comprising:
  • a keyboard circuit including key switches
  • tone generator associated with said key switches and producing tone signals over a range of frequencies having harmonic components and being of a frequency selectively determined by said key switches
  • variable filter means having a frequency characteristic determined by a controlling DC voltage, said variable filter means being operatively connected to said tone determined in accordance with the corresponding frequency of said tone generator resulting when the respective key switches are actuated thereby providing the desired output characteristics of said variable filter.
  • a monophonic electronic musical instrument according to claim 1 in which'said means for producing said controlling DC voltage comprises a frequency-to-voltage converter connected to produce an output DC signal whose voltage is proportional to the frequency of the tone generator signal.
  • variable filter comprises a field effect transistor as a controlling element to change the value of resistance between the source and drain of the transistor in accordance with the controlling DC voltage.
  • a monophonic electronic musical instrument comprising:
  • variable filter whose frequency characteristic is shifted in accordance with said controlling voltage
  • said output characteristics of the filter being variable so as to prevent the distortion of tone color and volume when the tonal height changes
  • said means for producing a controlling DC voltage comprising a frequency-towoltage converter arranged to produce an output DC signal having a voltage that is dependent on the frequency of the tone generator signal.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Electrophonic Musical Instruments (AREA)
US842547A 1968-07-19 1969-07-17 Monophonic electronic musical instrument with variable filter Expired - Lifetime US3614288A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP43050567A JPS499371B1 (enrdf_load_stackoverflow) 1968-07-19 1968-07-19

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US3614288A true US3614288A (en) 1971-10-19

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JP (1) JPS499371B1 (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3749807A (en) * 1971-04-14 1973-07-31 T Adachi Orchestral effect producing system for an electronic musical instrument
US3886836A (en) * 1973-04-11 1975-06-03 Nippon Musical Instruments Mfg Electronic musical instrument capable of generating tone signals having the pitch frequency, tone color and volume envelope varied with time
US3897709A (en) * 1973-04-11 1975-08-05 Nippon Musical Instruments Mfg Electronic musical instrument
US3902396A (en) * 1973-04-19 1975-09-02 Nippon Musical Instruments Mfg Electronic musical instrument
US3949639A (en) * 1974-01-10 1976-04-13 Nippon Gakki Seizo Kabushiki Kaisha Voltage controlled type electronic musical instrument
US3952624A (en) * 1973-11-02 1976-04-27 Nippon Gakki Seizo Kabushiki Kaisha Electronic musical instrument capable of generating tone signals having pitch frequency, tone color and volume envelope varied with time
US3978754A (en) * 1974-02-28 1976-09-07 Nippon Gakki Seizo Kabushiki Kaisha Voltage controlled type electronic musical instrument
US4023455A (en) * 1975-12-17 1977-05-17 Peterson Richard H Circuit for imitating the speech characteristics of reed organ pipes

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59127670U (ja) * 1983-02-14 1984-08-28 森田　安彦 ゲ−トボ−ルの練習用標的

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2606969A (en) * 1946-01-17 1952-08-12 Myron T Smith Method and system for reducing noise in the transmission of electric signals
US2606970A (en) * 1946-01-19 1952-08-12 Myron T Smith Method of and system for reducing noise in the transmission of signals
US2606973A (en) * 1946-01-17 1952-08-12 Myron T Smith Electric filter
US2606971A (en) * 1946-01-19 1952-08-12 Myron T Smith Method and system for reducing noise in the transmission of electric signals
US2606972A (en) * 1946-01-23 1952-08-12 Myron T Smith System for reducing noise in the transmission of electric signals
US3316341A (en) * 1963-11-29 1967-04-25 Columbia Records Distrib Corp Electrical musical instruments
US3497605A (en) * 1967-12-04 1970-02-24 Jasper Electronics Mfg Corp Circuit for obtaining repeater and percussion effects in an electrical musical instrument utilizing a field effect transistor
US3510567A (en) * 1966-11-28 1970-05-05 Sarkes Tarzian Tremolo amplifier circuit utilizing a field effect transistor
US3525796A (en) * 1966-11-08 1970-08-25 Philips Corp Electronic musical instrument provided with generators and individual formant filters

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2606969A (en) * 1946-01-17 1952-08-12 Myron T Smith Method and system for reducing noise in the transmission of electric signals
US2606973A (en) * 1946-01-17 1952-08-12 Myron T Smith Electric filter
US2606970A (en) * 1946-01-19 1952-08-12 Myron T Smith Method of and system for reducing noise in the transmission of signals
US2606971A (en) * 1946-01-19 1952-08-12 Myron T Smith Method and system for reducing noise in the transmission of electric signals
US2606972A (en) * 1946-01-23 1952-08-12 Myron T Smith System for reducing noise in the transmission of electric signals
US3316341A (en) * 1963-11-29 1967-04-25 Columbia Records Distrib Corp Electrical musical instruments
US3525796A (en) * 1966-11-08 1970-08-25 Philips Corp Electronic musical instrument provided with generators and individual formant filters
US3510567A (en) * 1966-11-28 1970-05-05 Sarkes Tarzian Tremolo amplifier circuit utilizing a field effect transistor
US3497605A (en) * 1967-12-04 1970-02-24 Jasper Electronics Mfg Corp Circuit for obtaining repeater and percussion effects in an electrical musical instrument utilizing a field effect transistor

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3749807A (en) * 1971-04-14 1973-07-31 T Adachi Orchestral effect producing system for an electronic musical instrument
US3886836A (en) * 1973-04-11 1975-06-03 Nippon Musical Instruments Mfg Electronic musical instrument capable of generating tone signals having the pitch frequency, tone color and volume envelope varied with time
US3897709A (en) * 1973-04-11 1975-08-05 Nippon Musical Instruments Mfg Electronic musical instrument
US3902396A (en) * 1973-04-19 1975-09-02 Nippon Musical Instruments Mfg Electronic musical instrument
US3952624A (en) * 1973-11-02 1976-04-27 Nippon Gakki Seizo Kabushiki Kaisha Electronic musical instrument capable of generating tone signals having pitch frequency, tone color and volume envelope varied with time
US3949639A (en) * 1974-01-10 1976-04-13 Nippon Gakki Seizo Kabushiki Kaisha Voltage controlled type electronic musical instrument
US3978754A (en) * 1974-02-28 1976-09-07 Nippon Gakki Seizo Kabushiki Kaisha Voltage controlled type electronic musical instrument
US4023455A (en) * 1975-12-17 1977-05-17 Peterson Richard H Circuit for imitating the speech characteristics of reed organ pipes
DE2657039A1 (de) * 1975-12-17 1977-06-23 Richard Henry Peterson Schaltungsanordnung zum nachahmen der klangcharakteristik von zungen-orgelpfeifen

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JPS499371B1 (enrdf_load_stackoverflow) 1974-03-04

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