Filtering Patents (Class 84/DIG9)
  • Patent number: 4351219
    Abstract: A tone generation system intended primarily for use in electronic musical instruments wherein a digital representation of a harmonically rich waveform is sampled, and a musical tone is produced therefrom. The stored waveform could be the four term Blackman-Harris window function, which has negligible side lobes and thus greatly attenuated higher harmonics. The stored function is read out at a fixed rate, but the time periods between successive readings of the waveform are varied to thereby vary the frequency of the output signal.
    Type: Grant
    Filed: September 25, 1980
    Date of Patent: September 28, 1982
    Assignee: Kimball International, Inc.
    Inventor: Steven C. Bass
  • Patent number: 4328731
    Abstract: An electronic tone generator capable of providing improved musical and tone quality by providing a primary melody and a secondary melody such as an accompaniment or the like is provided. The electronic tone generator of the instant invention is characterized by the use of a primary electronic scale generator circuit for producing a primary scale signal representative of a primary melody scale and a secondary electronic scale generator circuit for producing a secondary scale signal that is representative of a secondary melody and that is distinct from the primary scale signal. The primary scale signal and second scale signal are respectively shaped and summed and thereafter applied to an electro-acoustic transducer in order to produce music having a primary melody and secondary melody of considerable musical quality.
    Type: Grant
    Filed: July 17, 1978
    Date of Patent: May 11, 1982
    Assignee: Kabushiki Kaisha Suwa Seikosha
    Inventors: Mitsuhiro Gotho, Masayuki Ikeda, Hidetoshi Komatsu, Takahiro Naka
  • Patent number: 4322995
    Abstract: There is disclosed herein a music synthesizer which responds to a music note played by a music instrument. The synthesizer has an envelope generator which generates a control signal in relation to the input signal to control the loudness of the synthesized note. Also, the synthesizer has a pair of voltage controlled oscillators, one of which provides a signal having a frequency related to the frequency of the input note, and the other of which provides a signal having a frequency related to the frequency of the input signal offset by the ratio of the difference between a programmed note and a referenced note, such as A440. The programmed note is that note following the operation of a control switch. The synthesizer further includes a series of footpads which control various functions of the synthesizer, such as programming the programmed note, to allow the user to control the synthesized sound while playing an instrument.
    Type: Grant
    Filed: January 19, 1981
    Date of Patent: April 6, 1982
    Inventor: Donald L. Tavel
  • Patent number: 4306480
    Abstract: An electronic musical instrument having a fret board and a plurality of conductive frets may be coupled to a resistance ladder of discrete resistive elements. A conductive wire or a plurality of such wires selectively making contact with at least one of the conductive frets forms, together with the resistance ladder, part of a tone generating circuit. The circuit includes an oscillator which generates a tone in response to the conductive fret with which the wire makes contact. The circuit may also include a wave shaping circuit which selectively alters the shape of the generated tone and through a series of gradations alters its operating characteristics from that of a full wave rectifier to a linear voltage follower. Another embodiment modulates the phase of the generated tone by exploiting the dynamic impedance of a diode. One or more unique pressure sensitive touch pads may be employed for a glissando effect and/or for volume and/or tone glides.
    Type: Grant
    Filed: March 29, 1977
    Date of Patent: December 22, 1981
    Inventors: Frank Eventoff, Serge A. Tcherepnin
  • Patent number: 4300435
    Abstract: In an electronic musical instrument, such as an electronic organ, certain organ voices are synthesized by applying a tone signal to a voltage controlled low-pass sharp cutoff filter, the pass characteristic of which has a relatively sharp knee and a rapid rate of rolloff, thereby to sharply attenuate the harmonics contained in the tone signal which have frequencies above the cutoff frequency. The filter works on the principle that by switching one or more frequency-determining resistors in and out of the filter network at a rapid rate and varying the time on versus the time off, the effective value of the resistance varies to thereby alter the cutoff frequency and the character of the resulting sound signal. In accordance with the present invention, precise control over the switching duty cycle is achieved by establishing a reference voltage to which is added a voltage increment according to a binary weighting determined by selection of a particular organ voice.
    Type: Grant
    Filed: November 24, 1980
    Date of Patent: November 17, 1981
    Assignee: CBS Inc.
    Inventor: George F. Schmoll, III
  • Patent number: 4276802
    Abstract: An electronic keyboard instrument generates signals of frequencies respectively corresponding to keys by depressing the keys of a keyboard from a signal source, and reproduces a musical note corresponding to the generated signal. The frequency spectrum of an external signal is detected and used to control the frequency spectrum of the generated signal to cause the frequency spectrum of the generated signal to approximate that of the external signal.
    Type: Grant
    Filed: April 3, 1979
    Date of Patent: July 7, 1981
    Assignee: Keio Giken Kogyo Kabushiki Kaisha
    Inventor: Fumio Mieda
  • Patent number: 4265158
    Abstract: An elementary digital filter comprising an arithmetic logic unit with associated registers and timing circuits, simulates a current and a voltage in a corresponding elementary analog filter. The frequency response character of this elementary digital filter is changed when a coefficient used in the simulation or the sampling period used as the data renovation cycle of the simulation is changed. A digital filter circuit is composed of such an elementary digital filter or a combination of such elementary digital filters. A time function is passed through this composed digital filter circuit, and the output of the digital filter circuit is converted to an analog voltage to produce a musical tone. The tone quality of the produced musical tone is determined by the original waveform of the time function and the frequency response character of the composed digital filter circuit.
    Type: Grant
    Filed: October 12, 1979
    Date of Patent: May 5, 1981
    Inventor: Shuichi Takahashi
  • Patent number: 4248122
    Abstract: There is disclosed herein a music synthesizer which responds to a music note played by a music instrument. The synthesizer has an envelope generator which generates a control signal in relation to the output signal to control the loudness of the synthesized note. Also, the synthesizer has a pair of voltage controlled oscillators, one of which provides a signal having a frequency related to the frequency of the input note, and the other of which provides a signal having a frequency related to the frequency of the input signal offset by the ratio of the difference between a programmed note and a referenced note, such as A440. The programmed note is that note following the operation of a control switch. The synthesizer further includes a series of footpads which control various functions of the synthesizer, such as programming the programmed note, to allow the user to control the synthesized sound while playing an instrument.
    Type: Grant
    Filed: June 7, 1979
    Date of Patent: February 3, 1981
    Inventor: Donald L. Tavel
  • Patent number: 4248123
    Abstract: An electronic musical instrument using continuous tone generators capable of simulating the sounds of a conventional acoustical piano. The instrument includes a gating circuit featuring a timed switch travel circuit having a double-time constant for improved control of the dynamic range from the keyboard, and a soft pedal controlling the keying voltage to produce more realistic emulation of the dynamic effects of an acoustical piano. The gating circuit produces a double-time-constant envelope of nearly harmonically related signals for a more realistic piano timbre. The tone spectrum is also controlled as a function of signal level by means of a resistor matrix feeding selected inputs of an active ladder filter, in order to reproduce timbre variation with dynamic level.
    Type: Grant
    Filed: April 25, 1979
    Date of Patent: February 3, 1981
    Assignee: Baldwin Piano & Organ Company
    Inventors: David A. Bunger, Dale M. Uetrecht
  • Patent number: 4248121
    Abstract: An electronic organ tone generating technique produces a harmonic equivalent of a sawtooth wave. In one embodiment square waves generated by a conventional tone generator are applied to a one shot multivibrator, the output of which is a series of narrow rectangular pulses having a flat harmonic spectrum with both even and odd harmonics present. The narrow rectangular pulses are applied to a 3db per octave filter to produce a waveform, the harmonic content of which is equivalent to that of a sawtooth wave. In this embodiment, the pulse width remains constant regardless of the frequency of the pulse train. In a second embodiment, the duty cycle at each octave when moving up the keyboard is doubled to compensate for amplitude falloff which may occur in the filtered signal.
    Type: Grant
    Filed: August 31, 1979
    Date of Patent: February 3, 1981
    Assignee: Whirlpool Corporation
    Inventor: Patrick S. Roberts
  • Patent number: 4238985
    Abstract: An electronic musical instrument of a type capable of producing a musical tone corresponding to the tone pitch of a depressed key by controlling oscillation frequency of a voltage-controlled type oscillator by a pitch voltage corresponding to the tone pitch, wherein musical tone elements such as tone pitch and tone color are controlled in accordance with a control voltage which is produced for each individual key but is different from the pitch voltage.A temperature curve can be determined by controlling the tone pitch of the musical tone by this control voltage as well as by the pitch voltage. A desired temperament curve can be obtained by suitably adjusting the values of the control voltage for the respective keys. The tone color control is effected by varying the cut-off frequency of the voltage-controlled type filter in accordance with the aforementioned control voltage.
    Type: Grant
    Filed: September 15, 1978
    Date of Patent: December 16, 1980
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventor: Takeshi Adachi
  • Patent number: 4236436
    Abstract: An electronic music synthesizer capable of simulating a wide variety of musical effects, wherein the settings which create the various effects are hard wired on a plurality of selectable circuit boards so that programming of the instrument can be accomplished by the player with minimum effort. The synthesizer encodes a plurality of keys on the keyboard and selects a tone from the tone generator corresponding to the depressed key. This tone is fed through a chain of dividers to create the needed footages, which are then fed to voicing cards that create the different tone sources for the synthesizer. These tone sources are fed into a state variable active filter which modifies the timbre of the tone sources in order to achieve the desired frequency-related effects.
    Type: Grant
    Filed: November 8, 1978
    Date of Patent: December 2, 1980
    Assignee: Kimball International, Inc.
    Inventors: Ralph N. Dietrich, John W. Robinson, Stephen L. Howell
  • Patent number: 4236434
    Abstract: An electronic musical instrument for producing a vocal sound signal comprising a musical tone signal generator connected to a passing circuit for passing a musical tone signal under the selection of a key. A formant filter is connected in the passing circuit and includes a plurality of filters connected in parallel to one another. A control system is operative to produce two output signals in the passing circuit after the formant filter in sequence upon operation of the key, one of the output signals being a vowel sound and the other a consonant sound.
    Type: Grant
    Filed: April 19, 1979
    Date of Patent: December 2, 1980
    Assignee: Kabushiki Kaisha Kawai Sakki Susakusho
    Inventor: Koji Nishibe
  • Patent number: 4228713
    Abstract: In order to tune the frequency characteristics of a filter or oscillator as an exponential function of the position of a note on a musical scale, a pulse stream with an exponentially scaled duty cycle is used to gate an on-off switch which controls an electronic tuning signal for the first or second stage of the filter or oscillator. The pulse stream source can be a pulse code generator responsive to a priority note generator, or it can be an oscillator-driven one-shot with an exponentially scaled power supply governing the charging rate of a reactive component which determines the one-shot cycle time. There are also pitch offset and pitch modulation features in the circuit, the latter being usable in a constant deviation or a constant interval mode.
    Type: Grant
    Filed: July 3, 1978
    Date of Patent: October 21, 1980
    Assignee: Norlin Industries, Inc.
    Inventor: Glenn Gross
  • Patent number: 4218950
    Abstract: A multiple-stage active RC distributed filter having multiple inputs and a single output for producing filtering of large groups of notes for tone coloration in electronic musical instruments. Output signals from the keying circuits may be applied to selected input stages of the filter through a resistor matrix to produce the desired tone coloration. Voicing may be further modified by one or more compensation networks at the filter output.
    Type: Grant
    Filed: April 25, 1979
    Date of Patent: August 26, 1980
    Assignee: Baldwin Piano & Organ Company
    Inventor: Dale M. Uetrecht
  • Patent number: 4216691
    Abstract: An electronic organ uses several top octave synthesizer circuits for producing the various tones used in the organ. Each of the top octave synthesizers is capable of producing any tone which can be produced by the organ. As a consequence, the outputs of each synthesizer are applied to a coupler circuit, which in turn is connected to an octave assignment switching tree for directing the tones coupled to the inputs of the switching tree to individual leads, each corresponding to a different octave in the range of tones produced by the organ. The similar octave leads from each of the different octave switching circuits are connected together to common flute octave buses, so that the filters connected to the output buses have substantially fewer tones appearing at the input than one which would have the full tone range of the organ. Typically, the range of tones appearing at a filter input is one octave or less.
    Type: Grant
    Filed: January 9, 1978
    Date of Patent: August 12, 1980
    Assignee: C. G. Conn, Ltd.
    Inventor: Eric R. Bean
  • Patent number: 4214502
    Abstract: A special effects circuit for use in an electronic musical instrument, preferably an electronic organ, including a filter circuit having variable bandpass characteristics and a tone source supplying a signal to the input of the filter circuit. The bandpass characteristics of the filter circuit are modified in accordance with a control signal. Upon the occurrence of an input signal, a control circuit provides the filter circuit with the control signal at a random or pseudo-random value. The instrument player may select the source of input signals from a variety of sources within the organ thereby determining the times or frequency at which the control signal changes but the value of the control signal is random or pseudo-random. The tone signal output from the filter circuit has randomly or pseudo-randomly attenuated frequency characteristics and is coupled to standard organ output circuits for audio presentation.
    Type: Grant
    Filed: February 7, 1978
    Date of Patent: July 29, 1980
    Assignee: Marmon Company
    Inventors: Robert J. Holpuch, Robert G. Mathias, Alan C. Young
  • Patent number: 4211138
    Abstract: A fixed formant filter for a digital electronic instrument of the type in which musical tones are generated from waveshape data calculated independently of frequency of the tone from constituent generalized Fourier components. The Fourier components are individually scaled by scale factors selected from a set of stored scale factors which define the transfer characteristic of the fixed formant filter. Each separately addressable stored scale factor corresponds to a different frequency value in the musical scale. A scale factor is selected for separately scaling each harmonic of the tone generated in response to the particular note of the musical scale keyed on the instrument. The selected scale factors may be modified by a frequency deviation signal to provide vibrato or other frequency modulation effects.
    Type: Grant
    Filed: June 22, 1978
    Date of Patent: July 8, 1980
    Assignee: Kawai Musical Instrument Mfg. Co., Ltd.
    Inventor: Ralph Deutsch
  • Patent number: 4205577
    Abstract: A polyphonic tone synthesizer in which two or more distinct voices are sounded by operation of a single key. While the voices have the same fundamental frequency, they are made audibly distinct by differing in harmonic content and differing in the shape of the envelope of the voice signal. The two or more voices are synthesized by alternately calculating master data lists of the amplitude values representative of points on the waveforms of the two voices, adding the two master data lists and converting the resulting values to an analog waveform by feeding the data to a digital-to-analog converter at a rate determined by the fundamental frequency of the note. The master data list for each voice is calculated repetitively during the time the key is operated by multiplying a set of coefficients with a set of sinusoid values and continuously scaling the resultant product by an envelope scale factor which changes with time to correspond to the desired envelope waveform.
    Type: Grant
    Filed: April 24, 1978
    Date of Patent: June 3, 1980
    Assignee: Kawai Musical Instrument Mfg. Co. Ltd.
    Inventor: Ralph Deutsch
  • Patent number: 4192210
    Abstract: A fixed formant filter for a digital tone generator uses a set of scale factors generated by storing in memory a set of words corresponding to the relative amplitude of points on a single resonance curve. The words are addressed and read out of the memory in sequence in response to a counter. For each output state of the counter a group of words is read out of the memory, added, and stored as one scale factor of said set of scale factors. The number of words in the group read out corresponds to the number of resonant peaks in the fixed formant filter. The respective words in the group are addressed by modifying the output of the counter respectively by four constants corresponding to the relative position in the musical scale at which the resonant peaks of the formant filter occur.
    Type: Grant
    Filed: June 22, 1978
    Date of Patent: March 11, 1980
    Assignee: Kawai Musical Instrument Mfg. Co. Ltd.
    Inventor: Ralph Deutsch
  • Patent number: 4191082
    Abstract: An electronic musical instrument having the key range divided into upper and lower divisions, including a logical circuit converting the change-over position outputs of a key range dividing position selecting switch into gate control signals specifying corresponding key range dividing positions and a plurality of gates controlled by these gate control signals, thereby controlling the distributive mode of keyed tone signals to different tone color filters.
    Type: Grant
    Filed: October 11, 1978
    Date of Patent: March 4, 1980
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventor: Masahiko Koike
  • Patent number: 4185529
    Abstract: A digital organ or like electronic musical instrument of a real time processing system which produces musical notes by synthesizing weighted square waves and applying them to a digital filter of a transfer characteristic controlled for each square wave. Key information from a keyboard is detected by a key code generator having a key switch matrix in which key switches are grouped into a plurality of blocks. The key switches are scanned for each block and when one or more key switches of the block are closed, the scanning is stopped until after the closure information is sent out as binary coded information to a key code data assignor in accordance with priority. The key code data assignor applies envelope control signals to an envelope generator and an N-degree square wave generator. The envelope generator is a cyclic digital filter whose filter constant is controlled to provide desired envelope waveshape data for input to a multiplier.
    Type: Grant
    Filed: December 1, 1977
    Date of Patent: January 29, 1980
    Assignee: Kabushiki Kaisha Kawai Gakki Seisakusho
    Inventor: Hiroshi Kitagawa
  • Patent number: 4178824
    Abstract: An electronic musical instrument is provided with a single controlled type signal processing circuit for processing multiplexed tone source signals corresponding to depressed keys and a circuit for preferentially selecting one of tone identifying signals corresponding to the depressed keys. The characteristic of the signal processing circuit is controlled by a tone pitch signal generated in accordance with the tone identifying signal thus selected, so as to reduce the number of a signal processing circuits.
    Type: Grant
    Filed: December 21, 1977
    Date of Patent: December 18, 1979
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Eiichiro Aoki, Shigeru Yamada
  • Patent number: 4176577
    Abstract: In an electronic musical instrument comprising a keyboard including a plurality of keys, a frequency information memory device for storing frequency informations corresponding to respective keys, a plurality of musical tone forming means including a waveshape memory device for forming musical tones in response to the output of the frequency information memory device, and a shift circuit interposed between the frequency information memory device and the musical tone forming means for effecting a footage change of an octave unit, there is provided a preset circuit for applying a plurality of preset footage signals to the shift circuit and for applying another preset signals which are necessary to form musical tones to the musical tone forming means.
    Type: Grant
    Filed: October 27, 1977
    Date of Patent: December 4, 1979
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Shigeru Yamada, Kiyoshi Ichikawa
  • Patent number: 4175463
    Abstract: A tone synthesizer in which a musical tone of selected fundamental frequency is generated with a resonance effect at selected harmonics of the tone. The resonance effect is produced by adding an amplitude modulated carrier signal to the musical tone, the carrier signal being modulated by a signal having the fundamental frequency of the musical tone and the carrier frequency being an integral multiple of the fundamental.
    Type: Grant
    Filed: December 5, 1977
    Date of Patent: November 27, 1979
    Assignee: Kawai Musical Instrument Mfg. Co. Ltd.
    Inventor: Ralph Deutsch
  • Patent number: 4173915
    Abstract: A programmable dynamic filter for use with a time-shared electronic organ or the like includes a filter circuit responsive to a logical state of a control signal for tracking notes generated by the instrument. Means are provided for programming the filter independently of generated notes by selectively adjusting the pulse width of the control signal to achieve desired musical effects.
    Type: Grant
    Filed: June 29, 1978
    Date of Patent: November 13, 1979
    Assignee: Norlin Industries, Inc.
    Inventor: Glenn M. Gross
  • Patent number: 4134321
    Abstract: In an electronic musical instrument a demultiplexing audio waveshape generator, which accepts multiplexed frequency signals and generates a complex audio waveshape. This is accomplished by having a multiplexed frequency source with one or more outputs with each output being individually connected to a weighted resistor. The outputs of the resistors are connected in common to create a current source for presentation to an analog switch. The analog switch selects the multiplexed channels to be combined to produce the audio output signal, and through the use of gating signals can be made to create pulsed waveshapes. In the preferred embodiment of the present invention the signal from the analog switch is presented to a capacitance-resistance combination. The switched current presented to the capacitor causes an incremental charging and discharging of the capacitor which corresponds to the desired contribution of that particular channel to the audio output signal.
    Type: Grant
    Filed: April 14, 1977
    Date of Patent: January 16, 1979
    Assignee: Allen Organ Company
    Inventor: Robert P. Woron
  • Patent number: 4106384
    Abstract: A variable filter circuit, especially for synthesizing and shaping tone signals, in which a variable light source is provided which influences light sensitive resistor elements in the filter circuit. The variable circuit, by the use of selector switches, can provide different musical features, such as muted voices, percussion, brass, woodwind and the like, all of which will enhance, for example, existing organ voicing while it is, furthermore, possible to obtain the effect of playing a solo instrument together with organ voicing.
    Type: Grant
    Filed: May 21, 1976
    Date of Patent: August 15, 1978
    Assignee: Kimball International, Inc.
    Inventors: Billy J. Whittington, John William Robinson, Ralph N. Dietrich
  • Patent number: 4080861
    Abstract: In an electronic musical instrument, in particular an electronic organ, comprising a circuit for electrically modifying a musical tone by frequency modulation to provide an ensemble effect. The circuit comprises three series connected shift registers which operate as delay circuits and which are driven by three high-frequency oscillators. The oscillators are driven by three vibrato signals. The vibrato signals are out of phase with each other so that each of the clocks is driven by a differently phased signal. The outputs of the shift registers are filtered and are then recombined either electrically or acoustically or both so that a chorus effect is produced. Additionally, the output of the last shift register in the series combination may be fed back to the input of the first shift register in the series combination to introduce additional phase delay in the audio signal for richer ensemble effects.
    Type: Grant
    Filed: July 9, 1976
    Date of Patent: March 28, 1978
    Assignee: Thomas International Corporation
    Inventor: John Douglas Wholahan
  • Patent number: 4074605
    Abstract: A keyboard operated electronic musical instrument such as an electronic organ is disclosed which generates a musical tone signal by mixing together two different musical tone signals of different waveforms and which changes the sound of the generated musical tone by changing a the amount of mixing of the two signals. A clipping gate with a so-called sustain function is included for controlling the attenuation of an input signal as it passes to an output terminal while clipping the input signal gradually and smoothly so that the musical tone does not disappear instantly but attenuates gradually after the release of a depressed key. The input signal to the clipping gate circuit is a square wave signal, and a square wave signal derived at an output thereof is converted to a waveform other than a square wave.
    Type: Grant
    Filed: May 11, 1976
    Date of Patent: February 21, 1978
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Junnosuke Shigeta, Tomiji Munehiro
  • Patent number: 4056996
    Abstract: A monophonic system includes means for voicing only tones derived in response to depression of a key associated with the highest pitched note when several keys are struck at approximately the same time, regardless of the order in which the keys are struck. If several keys are released at approximately the same time, only the tones derived in response to the highest remaining activated key are voiced, regardless of the release sequence. In response to the system being played legatissimo, voiced tones gradually shift in frequency, i.e., portamento is achieved. In response to the system being played staccatissimo, voiced tones shift in frequency in discrete steps.
    Type: Grant
    Filed: June 23, 1975
    Date of Patent: November 8, 1977
    Assignee: D. H. Baldwin Company
    Inventor: David A. Bunger
  • Patent number: 4044642
    Abstract: A touch sensitive device is associated with at least one key of an electronic musical instrument such as an electronic organ, includes a layer of a pressure responsive, variable conductance material, and exhibits a switching action when subjected to pressure beyond a threshold pressure, any increase in pressure thereafter providing an increase in conductance up to a saturation pressure. The device may be used either as a combined switch and amplitude control or may be used in associated with one or more capacitors to provide either a high pass or low pass touch-control audio filter. In a totally polyphonic instrument a tone generator and touch-control filter are respectively associated with and responsive to each key depression, the output signal from each activated filter being coupled preferably to audio mixer circuitry.
    Type: Grant
    Filed: October 29, 1974
    Date of Patent: August 30, 1977
    Assignee: ARP Instruments, Inc.
    Inventors: Alan R. Pearlman, Dennis P. Colin
  • Patent number: 4023455
    Abstract: In an electronic musical instrument, such as an electronic organ, the speech characteristics of reed organ pipes are simulated by applying pulses produced by key-actuated tone generators, which pulses are preferably narrow as compared to their repetition frequency, to a low-pass filter, the pass characteristic of which has a relatively sharp knee and a very rapid rate of rolloff, thereby to sharply attenuate the harmonics contained in the pulse which have frequencies above the cutoff frequency. The resultant tone passed by the filter is surprisingly reed-like in character, and by changing the cutoff frequency, reed-like voices of differing properties, imitative for example, of an organ Oboe tone, an orchestral Oboe tone, a Clarinet, a Kinura or a Trompette are obtained.
    Type: Grant
    Filed: December 17, 1975
    Date of Patent: May 17, 1977
    Inventor: Richard H. Peterson
  • Patent number: 4018126
    Abstract: Apparatus is provided for use in electronically creating music or special sound effects through the generation and modification of audio frequency, electrical, tone sequence signals. The apparatus is characterized by its ability to generate random, as well as cyclically patterned, tone sequences; by the degree of control provided over both basic parameters of generation and a number of available special modifying effects; and by the reliability of the apparatus and the relative economy with which it may be maufactured. The preferred form of apparatus employs functional stages or modules largely implemented with solid state components. Among the novel functional modules utilized in the apparatus is an improved type of low pass, electronic R-C ladder filter employing diodes and fixed value capacitances, rather than transistors or/and variable value capacitances.
    Type: Grant
    Filed: March 26, 1975
    Date of Patent: April 19, 1977
    Inventor: Brian I. Walmann
  • Patent number: 4000679
    Abstract: A color organ device for producing a visual display of lights responsive to electrical signals produced on respective channels of a four-channel stereo. The device includes a housing having a plurality of banks of lights therein which is rotated by an electric motor. A interpreter is provided for selectively separating the frequencies produced by the four-channel stereo for selectively energizing the banks of lights. Slip-rings are provided for making electrical contact between respective frequency discriminating circuits and the banks of lights.
    Type: Grant
    Filed: July 7, 1975
    Date of Patent: January 4, 1977
    Inventor: Richard E. Norman
  • Patent number: 3986426
    Abstract: A music synthesizer produces pitch-proportional voltages in a novel resistor network, uses these voltage via keyboard control to generate in a voltage-controlled oscillator a high frequency signal, being a multiple of all the harmonic frequencies desired, separates the individual harmonics, converts them to sine waves with voltage-controlled tunable tracking filters, blends the waves in desired proportions, introduces transients of attack, decay, sustain, and release of key into each note, and introduces appropriate vibrato. An alternate apparatus accepts an external signal and converts it to voltages proportional to frequency, whereby accompaniment on pitch, in "close harmony" or more distantly related, is provided.
    Type: Grant
    Filed: August 28, 1975
    Date of Patent: October 19, 1976
    Inventor: Mark Edwin Faulhaber
  • Patent number: 3978754
    Abstract: This invention provides an electronic musical instrument comprising a keyboard circuit for producing a pitch determining voltage signal representing the note of an operated key, a voltage controlled oscillator for producing a tone signal having a tone pitch determined by the pitch determining voltage signal, and a voltage controlled lowpass filter for imparting a desired tone color to the tone signal. The voltage controlled lowpass filter is responsive to the pitch determining voltage signal from the keyboard circuit to control the cutoff frequency of the voltage controlled lowpass filter in such a manner that the harmonic content of a higher tone signal is decreased from that of a lower tone signal.
    Type: Grant
    Filed: February 25, 1975
    Date of Patent: September 7, 1976
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventor: Takeshi Adachi
  • Patent number: 3974461
    Abstract: A voltage controlled filter for an electronic synthesizer incorporates a plurality of individual voltage controlled filter stages connected in cascade with a variable feedback interconnecting the input and output stages. Each of the stages is controlled by application of a series of pulses, with the period between successive pulses determining the cutoff frequency of the filter. Application of pulses to the filter stages at different pulse repetition rates changes the cutoff frequency of the filter and modifies the relative amplitudes of different frequency components of an audio signal to be passed by the filter. The filter is suited for use with high level signals and provides an extremely wide dynamic range through a very high signal-to-noise ratio.
    Type: Grant
    Filed: June 14, 1974
    Date of Patent: August 10, 1976
    Assignee: Moog Music, Inc.
    Inventor: David A. Luce
  • Patent number: 3960043
    Abstract: A filter circuit for use in a musical instrument, such as an electronic organ, eliminating undesirable keying transients introduced into the signals provided by tone generators of the organ. The filter circuit includes a bandpass filter filtering from the keyed tone generator signals frequencies which are below and above the desired audio frequency spectrum of the output sound.
    Type: Grant
    Filed: June 24, 1974
    Date of Patent: June 1, 1976
    Assignee: Warwick Electronics Inc.
    Inventor: John R. Brand
  • Patent number: 3956960
    Abstract: Formant filtering is implemented in a computor organ of the type disclosed in U.S. Pat. No. 3,809,786 by eliminating, attenuating or accentuating certain Fourier components included in each waveshape amplitude computation. A set of formant filter factors define the formant filter passband as a function of frequency, logarithmic frequency or Fourier component order. As each constituent Fourier component is independently evaluated, the component amplitude is scaled by the appropriate formant filter factor. The resultant synthesized musical tone includes only Fourier components within the defined passband, so that formant filtering effectively is implemented without the use of an actual filter.
    Type: Grant
    Filed: July 25, 1974
    Date of Patent: May 18, 1976
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventor: Ralph Deutsch
  • Patent number: 3952624
    Abstract: An electronic musical instrument comprising a voltage controlled oscillator, a voltage controlled filter, a voltage controlled amplifier and envelope generators. An output envelope of the envelope generator has various parameters such as rise time and decay time or times. The envelope generator is of the voltage controlled type so that the parameters of the output envelope of the envelope generator are controllable in response to parameter controlling voltages from a parameter controlling voltage generator. In an attempt to enhance performance effects a switch circuit is provided, in accordance with the invention, to interchange between a rise time controlling voltage and a decay time controlling voltage which are both coupled from the parameter controlling voltage generator to the envelope generator.
    Type: Grant
    Filed: November 1, 1974
    Date of Patent: April 27, 1976
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventor: Genichi Kawakami
  • Patent number: 3948139
    Abstract: An electronic musical synthesizer generates tone signals coupled to a controllable bandpass filter and a controllable low-pass filter. A plurality of voice switches are individually selectable to couple preset control voltages to the filters, and to enable potentiometers which can be adjusted to generate control voltages to vary the frequency characteristics of the filters, control the octave of the tone signals, and to control a modulation oscillator. When a variable/preset switch is set to a preset state, the potentiometers are disconnected and auxiliary sections of the selected voice switch presets voltages for the oscillator, the octave circuit and the filters.
    Type: Grant
    Filed: August 28, 1974
    Date of Patent: April 6, 1976
    Assignee: Warwick Electronics Inc.
    Inventors: Byron Melcher, Alden J. Carlson