US3598891A - Musical tone-forming circuitry including filter and random noise modulation - Google Patents

Musical tone-forming circuitry including filter and random noise modulation Download PDF

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Publication number
US3598891A
US3598891A US835516A US3598891DA US3598891A US 3598891 A US3598891 A US 3598891A US 835516 A US835516 A US 835516A US 3598891D A US3598891D A US 3598891DA US 3598891 A US3598891 A US 3598891A
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Prior art keywords
tone
signal
signals
filter
generator
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Expired - Lifetime
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US835516A
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English (en)
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Takeshi Adachi
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Nippon Gakki Co Ltd
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Nippon Gakki Co Ltd
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    • 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
    • G10H1/04—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos by additional modulation
    • G10H1/043—Continuous modulation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S84/00—Music
    • Y10S84/09—Filtering

Definitions

  • a whistle or grass reed sound is simulated by an electronic musical circuitry comprising a portamento-type oscillator, a tone coloring filter for providing a tone signal havingpredetermined harmonics as well as a fundamental, a noise generator, a low-pass filter for deriving frequency components below 30 Hz from a noise signal output of the noise generator, and a modulator for amplitude modulating the tone signal from the tone coloring filter with the noise signal components ofless than 30 Hz from the low-pass filter.
  • This invention relates to a tone-forming device for electronic musical instruments, and more particularly to a device capable of readily producing musical tones of special timbers resembling those of whistles or grass reeds which are usually difficult to produce by the conventional electronic musical instruments.
  • the conventional electronic musical instrument is usually so constructed as to produce various kinds of musical tones, e.g., musical tones similar to those ofa flute containing a relatively small quantity of high frequency components and musical tones similar to those of a reed instrument containing a relatively large quantity of high frequency components, by passing signals from tone generators through various tone coloring filters, whereby the desired musical signals having the desired tone colors are formed by selectively combining a signal of the fundamental frequency with different types of overtones in various level ratios.
  • musical tones e.g., musical tones similar to those ofa flute containing a relatively small quantity of high frequency components and musical tones similar to those of a reed instrument containing a relatively large quantity of high frequency components
  • the tone source signals containing the fundamental frequency and various overtones are subjected to balance modulation or amplitude modulation by a random signal containing frequency components of less than about 30 Hz.
  • FIG. 1 is a schematic block diagram of one embodiment of a tone-forming device for electronic musical instruments embodying this invention
  • FIGS. 2A, and 2B show preferred circuit arrangements of various circuits components shown in FIG. 1;
  • FIGS. 3A and 3B show the waveforms of typical modulated outputs produced by the modulation circuit shown in FIG. 1;
  • FIG. 4 shows an amplitude modulation circuit utilizing an FET that can be substituted for the balanced modulation circuit shown in FIG. 28.
  • FIG. 1 is a schematic block diagram of one embodiment of this invention, wherein tone signals are derived from a tone generator 11, which is used as the tone source of a conventional electronic musical instrument including a plurality of oscillators or preferably a portamento oscillator constructed in a manner to be described later. Tone signals from the tone generator 11 are passed through a tone coloring filter l2 to be converted into musical signals having desired tones similar to those of flute or reed instruments (oboe, bassoon, etc), and the converted signals are supplied to a balanced modulator (or an amplitude modulator) 13 to be described hereinafter.
  • tone signals are derived from a tone generator 11, which is used as the tone source of a conventional electronic musical instrument including a plurality of oscillators or preferably a portamento oscillator constructed in a manner to be described later. Tone signals from the tone generator 11 are passed through a tone coloring filter l2 to be converted into musical signals having desired tones similar to those of flute or reed instruments (
  • a random modulation signal is also supplied to the balanced modulator (or amplitude modulator) 13 from a source of random signal 14 comprising a white noise signal generator 15 (the construction thereof will be described latter in detail) and a low-pass filter 16 which passes only frequency components of less than, for example, 30 Hz. out of the white noise signals generated by the white noise signal generator 15.
  • a source of random signal 14 comprising a white noise signal generator 15 (the construction thereof will be described latter in detail) and a low-pass filter 16 which passes only frequency components of less than, for example, 30 Hz. out of the white noise signals generated by the white noise signal generator 15.
  • the balanced modulator (or amplitude modulator) 13 provides modulated musical signals resembling the musical signal of whistles or grass reeds having relatively unstable tone feelings which have been difficult to produce by conventional electronic musical instruments.
  • the musical signals thus modulated are provided by suitable modulating musical signals obtained from the tone generator 11 through tone coloring filter l2 and having relatively stable tone feelings resembling those of flute or reed instruments with random modulation signals'having frequency components of less than 30 Hz. which are generated by the white noise signal generator 15 and passed through low-pass pass filter 16.
  • Output musical signals from the balanced modulator (or amplitude modulator) 13 are amplified, if desired, by an amplifier 17 and are then transduced by a loudspeaker 18 into the desired musical sounds.
  • the musical sounds of whistles or grass reeds are characterized in that their fundamental frequency generally ranges from 500 Hz. to 4 kHz. their tone feelings are unstable, their musical pitch varies continuously and their amplitude varies irregularly with a maximum degree of modulation amounting to 30 to 50 percent.
  • the waveform of the whistle is substantially of a sine wave type containing small quantity of higher harmonics and resembling that of flutes, whereas the waveform of the grass reed contains a relatively large quantity of higher harmonics and resembling that of reed instruments.
  • the tone generator 11 When the tone generator 11 is so constructed as to selectively produce tone signals having a fundamental frequency ranging from 500 Hz. to 4 Hz., and when the tone coloring filter 12 is so designed as to suitably select the desired percentage of the high frequency contents of the tone signal, it is possible to produce tone signals resembling those of flute and reed instruments. It is also preferable to set the degree of modulation by the balanced modulator (or amplitude modulator) 13 at a range of from 30 to 50 percent. Further, it is preferably to form the tone generator 11 from a portamento oscillator, as the musical pitch of the tones selectively generated thereby can vary continuously.
  • the tone signals produced through the tone coloring filter l2 and resembling those of flute or reed instruments are subjected to balanced modulation (or amplitude modulation) l3 and are modulated with random modulation signals generated by the white noise signal generator 15 and passed through the low-pass filter 16 which acts to selectively pass only frequency components of less than about 30 Hz., with the result that the amplitude of the modulated musical signal outputs varies irregularly.
  • tone-forming device for electronic musical instruments can readily produce tone signals resembling those of whistles and grass reeds having relatively unstable tone feelings which heretofore have been difficult to produce by conventional electrical instruments, so that said device has a broader field of application.
  • the portamento oscillator serving as a tone generator 11 is a modified from of a Wiens bridge oscillator which comprises a plurality of oscillation frequency determining circuits 111a, lllb, 1110 and 111d including parallel circuits of resistors R1 la, R1 lb, R1 10, Rlld and capacitors Clla, 11b, C1 10, Clld and serial circuits connected therewith and including resistors R21a, R2Ib, R21c, R2ld and capacitors C210, C2Ib, C2Ic and C2ld.
  • Junctures between said parallel circuits and serial circuits involved in the respective oscillation frequency determining circuits are connected to the corresponding taps of an elongated bar resistor 113a respectively through emitter follower circuits 112a, 112b, 1126 and 112d.
  • the resistor 11311 is associated with the opposite electrically conductive flexible contact ll3b.
  • the oscillation frequency is determined by the position at which the contact 11311 is depressed for contact with the re sistor 1130
  • the signal having an oscillation frequency determined by the manner in which the fingerboard is operated is supplied to a phase dividing amplifier 114 which produces two outputs in the opposite phases.
  • the two outputs are supplied across the aforementioned frequency determining circuits.
  • an oscillation loop which includes the oscillation frequency determining circuits 111a to 111d, the emitter follower circuits [12a to the fingerboard 113, and the amplifier 1M.
  • This oscillation loop is normally open but is closed by the selective operation of any point of the fingerboard 113 to produce a tone signal having the frequency determined by the position of the particular point depressed.
  • Oscillation frequencies fa, fl), fc and fd of the oscillation frequency determining circuits 111a to 111d are given by Cl lc-CZlc-Rllc-Rllc Clld-CZld-Rl ld-RZld
  • the tone signals produced by the portamento oscillator 11 substantially has a sine waveform containing a relatively small quantity of higher harmonics, and resembling the waveform of musical signals produced by flutes.
  • the tone coloring filter 12 includes a clip circuit 121 and a tone coloring filter circuit 122 for obtaining the tones of a reed instrument. Either of the whistle and grass reed tones is selectively produced by means of a switch SW.
  • the signals produced by the portamento oscillator 11 substantially have a since wave containing relatively small quantity of high harmonics, it is only required to cause these signals to pass directly to tenninal X in order to form tone signals resembling the tones of flutes, whereas, to form tone signals resembling those of reed instruments, it is necessary to cause the signals to pass first through the clip circuit 121 so as to increase its percentage of higher harmonic content and then through the tone coloring filter circuit 122.
  • the white noise signal generator 15 in the random signal source 14 comprises a noise source 15a consisting of a transistor TR with a negative bias applied across its base and emitter electrodes (or a conventional diode may be used) to utilize the breakdown characteristic of the transistor and an amplifier 15b for amplifying the noise signal.
  • the white noise signal thus produced is passed through a 11 type low-pass filter 16 comprising a choke coil CH and two capacitors C1 and C2 so designed as to allow only frequency components of less than about Hz. to pass therethrough.
  • the balanced modulator 13 comprises a signal input transformer T1 connected to receive tone signals resembling those of flute or reed instruments and supplied through the tone coloring filter 12, an input transformer T2 connected to receive random signals supplied from the random signal generator 14 and having frequency components of less than 30 Hz and an output transformer T3 for deriving modulated signals, said transformers T1, T2 and T3 including magnetically coupled primary windings T1,, T2 and T3,, and secondary windings T1",,T2 and T3,, respectively.
  • a diode rectifier bridge circuit 131 including four diodes D1, D2, D3 and D4 which are connected to each other with the indicated polarities.
  • the opposite terminals of the secondary winding T1,, of the signal input transformer T1 are connected to the intermediate terminal CT on the secondary winding T2, of the modulating signal input transformer T2 and the intermediate terminal CT on the primary winding T3,, of the output transformer T3, respectively.
  • the output transformer T3 of the balanced modulator 13 provides a modulated musical signal V having relatively unstable tone feelings like the sounds of whistles or grass reeds, said modulated musical signal being obtained by subjecting the source signal Vc produced by the portamento oscillator 11 and passed through the tone coloring filter 12 and having tones resembling those of flutes or reeds to balanced modulation by a random modulation signal Vm produced by the white noise signal generator 15 and passed through the low-pass filter 16 and having frequency components of less than about 30 Hz., as shown in FIG. 3A.
  • the resultant output is reproduced by a loudspeaker 18 after being amplified by the amplifier 17, if desired.
  • FIG. 4 shows the circuit arrangement of an amplitude modulator having equivalent sound effects to those offered by the balanced modulator 13 and may be substituted therefor.
  • a field effect transistor F ET
  • F ET field effect transistor
  • the source signal Vc from the tone coloring filter 12 is supplied to the source terminal S (or drain terminal D instead) of the FE f, whereas the random modulating signal Vm having frequency components of less than about 30 Hz. is conducted to the gate terminal G through the low-pass filter 16, whereby an amplitude modulated musical signal V0, (see FIG. 33), having relatively unstable tone feelings like the tones of a whistle or grass reed is drawn out through the other drain terminal D (or source terminal S instead),
  • the invention provides a toneforming device for electronic musical instruments wherein the selective operation of the fingerboard of the electronic musical instruments enables musical signals of relatively unstable tone feelings similar to those of whistles and grass reeds, to be readily produced though the conventional musical instruments failed to generate such musical tone signals. Accordingly, the invention has a broader field of application.
  • a musical tone forming circuit comprising:
  • a tone generator including portamento-type oscillator means for producing a tone signal having gradually variable frequency:
  • tone coloring filter coupled to the output of said tone generator for producing a tone signal having a predetermined harmonics and a fundamental frequency:
  • a low-pass filter for deriving frequency components below 30 Hz. out of a noise signal from said white noise signal generator
  • an amplitude modulator for amplitude modulating a tone signal from said tone coloring filter with a noise signal from said low-pass filter.
  • said white noise signal generator comprises a negatively biased transistor circuit, the breakdown characteristic of said transistor being utilized in generating said white noise signals.
  • said amplitude modulator comprising a balanced modulation circuit including an input transformer for supplying tone signals obtained from said tone coloring filter, an input transformer for supplying the modulating signals obtained from said lowpass filter and an output transformer for taking out output signals obtained by modulating said tone signals with said modulating signals.
  • said amplitude modulator comprises a field effect transistor having its gate terminal grounded through a resistor one ofits source and drain terminals being connected to receive said tone signals from said tone coloring filter, said gate terminal being connected to receive the modulating signal from said low-pass filter and the other source of drain terminal being connected to couple the modulated signals to an output.
  • the tone signal from said tone coloring filter has a flu tone c olor.

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  • Engineering & Computer Science (AREA)
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US835516A 1968-06-25 1969-06-23 Musical tone-forming circuitry including filter and random noise modulation Expired - Lifetime US3598891A (en)

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JP43043743A JPS499370B1 (enrdf_load_stackoverflow) 1968-06-25 1968-06-25

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711620A (en) * 1970-01-29 1973-01-16 Tokyo Shibaura Electric Co Musical tone signal generator
JPS4839021A (enrdf_load_stackoverflow) * 1971-09-20 1973-06-08
US3754495A (en) * 1970-10-27 1973-08-28 M Honegger Sounding note board for music instruction
US3866505A (en) * 1972-07-20 1975-02-18 Nippon Musical Instruments Mfg Ensemble effect imparting device using a bucket brigade device for an electric musical instrument
US3867862A (en) * 1973-06-11 1975-02-25 Baldwin Co D H Electrical musical instrument
DE2657039A1 (de) * 1975-12-17 1977-06-23 Richard Henry Peterson Schaltungsanordnung zum nachahmen der klangcharakteristik von zungen-orgelpfeifen
JPS5337523U (enrdf_load_stackoverflow) * 1976-09-06 1978-04-01
US4276802A (en) * 1978-04-03 1981-07-07 Keio Giken Kogyo Kabushiki Kaisha Electronic keyboard instrument
US5848165A (en) * 1994-07-27 1998-12-08 Pritchard; Eric K. Fat sound creation means

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2483226A (en) * 1945-10-29 1949-09-27 Us Executive Secretary Of The Electronic noise generator
US2490487A (en) * 1945-10-29 1949-12-06 Stevens Stanley Smith Electronic noise generator
US2701305A (en) * 1951-09-15 1955-02-01 Bell Telephone Labor Inc Recognition circuit
US3004459A (en) * 1956-12-31 1961-10-17 Baldwin Piano Co Modulation system
US3197544A (en) * 1961-08-28 1965-07-27 Richard H Peterson Electronic musical instruments with twin detuning circuits to maintain constant vibrato
US3267199A (en) * 1964-03-04 1966-08-16 Hurvitz Hyman Systems for introducing vibrato
US3267197A (en) * 1964-01-22 1966-08-16 Hurvitz Hyman Reverberators
US3510567A (en) * 1966-11-28 1970-05-05 Sarkes Tarzian Tremolo amplifier circuit utilizing a field effect transistor

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2483226A (en) * 1945-10-29 1949-09-27 Us Executive Secretary Of The Electronic noise generator
US2490487A (en) * 1945-10-29 1949-12-06 Stevens Stanley Smith Electronic noise generator
US2701305A (en) * 1951-09-15 1955-02-01 Bell Telephone Labor Inc Recognition circuit
US3004459A (en) * 1956-12-31 1961-10-17 Baldwin Piano Co Modulation system
US3197544A (en) * 1961-08-28 1965-07-27 Richard H Peterson Electronic musical instruments with twin detuning circuits to maintain constant vibrato
US3267197A (en) * 1964-01-22 1966-08-16 Hurvitz Hyman Reverberators
US3267199A (en) * 1964-03-04 1966-08-16 Hurvitz Hyman Systems for introducing vibrato
US3510567A (en) * 1966-11-28 1970-05-05 Sarkes Tarzian Tremolo amplifier circuit utilizing a field effect transistor

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711620A (en) * 1970-01-29 1973-01-16 Tokyo Shibaura Electric Co Musical tone signal generator
US3754495A (en) * 1970-10-27 1973-08-28 M Honegger Sounding note board for music instruction
JPS4839021A (enrdf_load_stackoverflow) * 1971-09-20 1973-06-08
US3866505A (en) * 1972-07-20 1975-02-18 Nippon Musical Instruments Mfg Ensemble effect imparting device using a bucket brigade device for an electric musical instrument
US3867862A (en) * 1973-06-11 1975-02-25 Baldwin Co D H Electrical musical instrument
DE2657039A1 (de) * 1975-12-17 1977-06-23 Richard Henry Peterson Schaltungsanordnung zum nachahmen der klangcharakteristik von zungen-orgelpfeifen
JPS5337523U (enrdf_load_stackoverflow) * 1976-09-06 1978-04-01
US4276802A (en) * 1978-04-03 1981-07-07 Keio Giken Kogyo Kabushiki Kaisha Electronic keyboard instrument
US5848165A (en) * 1994-07-27 1998-12-08 Pritchard; Eric K. Fat sound creation means

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