Abstract: An amplifier circuit for automatically altering in a controlled way the reproduced tones of an electronic piano comprises a main signal path for the fundamental tones and an overtone path including a plurality of tone altering electronic networks and field effect transistor amplifiers combining the networks. The circuit includes separate controls for manual adjustment of normal level gain, bass boost, overtone, output volume and gate control threshold. A mixer recombines the main path and the overtone path. A gate circuit may be provided to disable the overtone path when no signal is present in the main path over a predetermined minimum threshold. The entire device is constructed for mounting over the keyboard of the piano, with a panel for the controls which renders them readily accessible for regulation by the musician to obtain the desired improvement and alteration of the tones put out by the piano.

Abstract: A musical tone is synthesized by frequency modulation which realizes a desired fixed formant. A first accumulator repeatedly adds a constant corresponding to a center frequency of the fixed formant at a regular time interval to generate phase angle data of a carrier. A second accumulator repeatedly adds a constant corresponding to a fundamental frequency of a selected note at a regular time interval to output a carry out signal each time the accumulated value has exceeded a predetermined modulo number. By resetting the first accumulator repeatedly by this carry out signal, the phase angle data of the carrier is brought into a harmonic relation with the fundamental frequency. By effecting frequency modulation using this phase angle data of the carrier and the fundamental or harmonic frequency of a selected note, a musical tone in which harmonic components of the selected note are controlled in accordance with the desired fixed formant is synthesized.

Abstract: An electronic musical instrument comprises a plurality of musical tone control units each having a tone waveform producing circuit, a volume envelope circuit, a filter circuit and other circuits. A given musical tone data can be preset in each musical tone control unit. Musical tone signals produced by the musical tone control units are synthesized to provide an effective musical tone.

Abstract: The disclosed organ employs keyboard-activated transfer of individualized tone and envelope-generating information from large memories for each distinctive set of a note's harmonics, to small memories in small circuits corresponding to each harmonic set. Selection of large memories programmed for different temperaments or voice types renders the organ playable as one or another type of organ (e.g., gothic, classical, romantic, theater) in a variety of temperaments (e.g., just-temperament, mean-tone, equal-temperament). Information transferred from any selected large memory causes a circuit common to one or more sets of a note's harmonics to sweep the harmonic data transferred to the small memories for all the note's harmonic sets, to generate respective currents representing attack and decay envelopes for all the note's harmonic sets.

Abstract: A predetermined frequency signal is amplitude modulated with a time window signal having a predetermined time width to simultaneously calculate a plurality of frequency components distributed over a predetermined frequency bandwidth and having the frequency component as a center component, and the plurality of frequency components thus calculated are used as partial tone components to form a musical tone signal. The frequency signal and the time window signal are formed by using a common function signal generator, on a time division basis, which produces the frequency signal and the time window signal. This construction makes it possible to form a musical tone having a great number of harmonic components at high speeds with a simple circuit construction.

Abstract: An automatic performing apparatus of an electronic musical instrument comprises a memory for storing musical note data representing progression of a music to be played and control data for controlling such a generation mode of music tones being generated as tone color and modulation effect. The generation mode of musical tone signals generated by a tone forming circuit in response to the musical note data read out of the memory is also automatically controlled by the control data read out of the memory.

Abstract: An electronic musical instrument comprising a tone generator, an accumulator and a digital filter. The tone generator generates musical tone signals each represented by sampled values, corresponding to depressed keys. The accumulator accumulates the sampled values of the musical tone signals at predetermined timings. The digital filter modifies an output of the accumulator in accordance with the amplitude-frequency characteristic of a predetermined formant characteristic. A musical tone is produced based on an output of the digital filter circuit, thereby the formant characteristic is imparted to the musical tone.This utilization of the digital filter for the musical instrument makes it possible to impart a formant characteristic to a musical tone without a complex circuit construction. Moreover the insertion of the accumulator following the tone generator makes it possible to use the digital filter of a low speed type.

Abstract: Computer organ tone input for alterable stops is achieved by single-key input through a decoded keyboard which is couple to a logic network and optoelectrical output drive circuitry. The decoder circuitry activates selected optical emitters in an array which is mounted in the optical reader of a computer organ such that the decoder circuitry is electronically isolated from the computer organ. The invention eliminates the need for a tone card library, does not interfere with the sensitive circuitry of the organ and permits instantaneous reprogramming of alterable voices.

Abstract: First to third switch contact pairs are provided for each of the performance keys of an electronic keyboard musical instrument such that they are successively closed in an interlocked relation to the operation of the associated key. A first time interval from the closure of the first switch contact pair till the closure of the second switch contact pair and a second time interval from the closure of the second switch contact pair till the closure of the third switch contact pair are counted in a CPU, and their ratio is obtained therein. The tone color of the output musical signal is controlled according to the value of this ratio, and the volume of the musical signal is controlled according to the length of the second time interval.

Abstract: A tone signal having been data compressed or expanded is obtained through a circuit for taking the sum of upper three bits of envelope data, a latch for storing the output of said circuit, a circuit for setting the extent of bit shift of digital tone data according to the output of said latch, a latch group for latching the tone data having been bit shifted according to the output of the setting circuit, and an amplifier, the amplification level of which is set according to the extent of bit shift and which receives and amplifies the bit shifted tone data from a digital-to-analog converter.

Abstract: A pipe organ in which information relevant to actuation of keys and stops at a console of the organ is stored in random access memory, and the specifications for stops are held in pre-programmed read only memory, the requirements for each pipe being examined in turn by scanning means.

Abstract: A musical tone is synthesized by controlling harmonic components of a note selected in a keyboard in accordance with a desired fixed formant. A parameter computation circuit detects a harmonic frequency which is nearest to a center frequency of the fixed formant and produces FM computation parameters using the nearest harmonic frequency as a carrier frequency and a fundamental or harmonic frequency of the selected note as a modulating frequency. A frequency modulation circuit performs an FM computation on the basis of these parameters and, as a result, a tone whose harmonic components have been controlled in accordance with a formant having the nearest harmonic frequency as a central component is synthesized. The parameter computation circuit computes frequency difference between the nearest harmonic frequency and the center frequency of the fixed formant for controlling the level of a formant synthesized in a frequency modulation circuit in accordance with this frequency difference.

Abstract: A tone quality presetting apparatus for use in an electronic musical instrument, arranged so that, when preset data of tone quality pattern are recalled from a memory to automatically set contents on tone quality setting members of manually operable setting units so as to establish agreement of the contents with the read-out preset data, the tone generator section of the musical instrument is controlled by the contents of the preset data during the period of time till the contents set on the setting members come to agree with the contents of the preset data, and that subsequent to the establishment of this agreement, the tone generator section is directly controlled by the contents set on the setting members, whereby the automatic setting operation of the setting members does not need to be performed at high speed and also the player is not bothered to pay attention to noises which otherwise would be generated in the setting members during automatic setting of contents thereon, and further that, during the pa

Abstract: An electronic musical instrument comprises a plurality of key switches and a key switch scanning circuit for sequentially scanning said key switches at a predetermined speed to produce time division multiplexed key data signals representing the depressed states of respective keys. The instrument further comprises a time division multiplexed tone waveform generating circuit which generates tone signals on a time division basis and in synchronism with the scanning of said key switches, said tone signals consisting of waveform samples of all the notes, i.e. tone frequencies, that the instrument can generate, and means which delivers out the output signal from the time division multiplexed tone waveform generating circuit at the moments when said time division multiplexed key data signals arrive, thereby producing plurality of tone signals in a time division multiplexed manner.

Abstract: A digital synthesizer primarily intended for use in electronic musical instruments which are microprocessor controlled includes a plurality of storage devices which contain numerical data commensurate with the characteristics of an output signal to be produced. Information is read out of these storage devices under the control of command signals having a predetermined repetition frequency. The generation of the command signals is controlled in such a manner as to permit the generation of harmonically related frequencies.

Abstract: A programmable tone generator for an electronic musical instrument generates a tone signal having a desired fundamental frequency and harmonic content. A binary counter serves as a time base for encoding each period of a tone signal waveform onto plural outputs in the form of a binary code. A plurality of programmable tone generation circuits are coupled with selected counter outputs to comprise plural tone signal branches, each providing a tone signal at a selected fundamental frequency and having selected harmonic content. A signal processing circuit associated with each tone signal branch includes a programmable variable code generator and determines the initial content of the output waveform, subsequently either maintaining or changing the fundamental frequency and harmonic content thereof.

Abstract: A plurality of sets of such characteristics as the color, volume and effect of a musical tone are preset for different musical composition fashions. Desired preset characteristics are selected independently in the melody performance portion and the accompaniment performance portion by operating a corresponding melody musical composition fashion selection switch and a corresponding accompaniment musical fashion selection switch thus establishing a musical tone having a desired musical composition fashion for each portion. According to a modified embodiment, when either one of the melody and accompaniment musical composition fashion selection switches is operated, both the musical composition fashions of the melody performance portion and the accompaniment portion are established in predetermined manner.

Abstract: A non-volatile memory system for an electronic musical instrument having a plurality of player actuatable instrument controls, comprises a readable, writable memory. The memory includes addressing inputs and data input/outputs. The data input/outputs are coupled with at least selected ones of the plurality of player actuatable instrument controls. Player actuatable memory controls are also provided for selecting either the memory or the selected ones of the player actuatable instrument controls for control of the instrument.

Abstract: In a musical instrument having one or more tone generators in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced points defining the waveform of one cycle of a musical signal are transferred sequentially from a note register to a digital-to-analog converter in repetitive cycles at a rate proportional to the pitch of the tone being generated, apparatus is provided for producing tones having independent time-varying harmonic components. A recursive algorithm is implemented which approximates prespecified harmonic-time curves by piecewise segments of exponential functions. Only a small number of stored curve parameters are required to generate the harmonic-time scale factor for a set of harmonic coefficients.

Abstract: An electronic musical instrument of a channel assignment type wherein depressed keys from among a larger plurality of keys are respectively assigned to a smaller plurality of tone producing channels for generating wave of musical tones. The assigner comprises a microprogram, an arithmetic section, a memory, and an interruption control circuit to assign the depressed keys to available tone producing channels. The current on-off information of the keys is subjected to calculation to form a key-on request file and a key-off request file. A tone request file is formed on a plurality of tone data as designated by the tone levers. A channel assignment table is formed, based on the key-on and key-off request files, to indicate a status of assigning the depressed keys to the tone producing channels.

Abstract: In an electronic musical instrument which is arranged to produce musical tones belonging to the selected one of many different types of musical instruments and having a number of player-operable selection keys respectively corresponding to the number of types of musical instrument sounds desired, the improvement wherein means is provided for generating a sample tone belonging to that type of musical instrument specified by one of the above-mentioned selection keys at a prescribed pitch and period simply by depressing only once a particular selection key, without taking the trouble of successively depressing individual performance keys, thereby facilitating the selection of a desired type of musical instrument by the player.

Abstract: Apparatus for eliminating feedback in stage monitors for selected musical instruments includes filter networks for attenuation of a broad frequency range including the entire range of frequencies contributing to the feedback. A combination of high order low-pass and high-pass filters is used to pass fundamental and second order components of a selected instrument, while attenuating the undesired feedback frequencies as well as extremely low range frequencies capable of damaging a speaker. A pair of passbands is provided, and a pair of frequency bands is suppressed, the two pairs providing alternate attenuation and pass-bands. Active filters having operational amplifiers and frequency selective circuits are used, along with buffering and summing circuits, to attain the desired frequency characteristic.

Abstract: Simultaneously played notes on a keyboard are automatically provided with different voice timbres. The assignment of voices to notes is by relative frequency-scale position within the chord. If four or more notes are played, the notes are scanned along the musical scale and the three lowest notes played and the highest note are sounded in different voices with the solo voice assigned to the highest note. Assignment of voices occurs automatically when fewer than four keys are played. Time division multiplex digital logic signals representative of the played keys are applied to a memory circuit and a comparator circuit. If the information stored in the memory from the previous scan cycle is unchanged the comparator provides an enabling signal to a monostable and enable logic circuit. A priority selector circuit provides logic information to the monostable and enable logic circuit which outputs this information and information representative of the total number of keys played.

Abstract: An electronic musical instrument includes a plurality of address generators for producing address signals corresponding to different tones each varying at a rate synchronous with the frequency of each of the different tones, a waveform memory device including a plurality of addresses for storing at respective addresses a plurality of waveform sample values that constitute a waveform, a circuit for sequentially supplying one after another of the address signals to the waveform memory device to read out the waveform in different rates in a time division multiplexed manner for different tones, and musical tone forming circuits for forming musical tones in accordance with the time division multiplexed waveform outputs of the waveform memory device.

Abstract: A buzz wave comprising n harmonic components having a flat spectrum envelope is generated according to a relatively simple algebraic expression which can be digitally computed by an arithmetic operation. Modifying harmonic components corresponding to the harmonic components to be emphasized or suppressed are also generated. The buzz wave and the modifying components are added or subtracted to form a desired musical tone signal.

Abstract: Apparatus for producing a chorale or vocal effect in an electronic musical instrument comprises means responsive to the playing keys of the instrument for producing an indexing signal and means responsive to the indexing signal for sequentially developing a plurality of control signals. A programmable filter is responsive to each sequentially developed control signal for modifying the harmonic content of a tone signal to simulate a different vowel-like sound for producing a vocal effect consisting of a sequence of different vowel-like sounds as the keys are played. The modified tone signal may be coupled through a chorus generator to simulate a chorale effect and the programmed characteristics of the filter may be modulated to further animate the performance as well as being made responsive to a glide signal for producing two different vowel-like sounds in succession at two different pitches in response to a glissando or portamento command.

Abstract: In an electronic musical instrument there are provided a channel processor which assigns tone production of a depressed key to one of musical tone producing channels which are smaller in number than total keys. The keys and channels are divided into groups respectively so that keys of one group are assigned to channels of a specific group. The relationship that which key group corresponds to which channel group is changed by an assignment mode changing circuit. Also a switch is provided for selecting a performance mode which switches the operation of the assignment mode changing circuit. Consequently, in one a performance mode all tone production channels are used solely by an upper or lower keyboard or key range while under another performance mode only some of the tone production channels are utilized for a particular keyboard or key range and the remaining tone production channels are utilized by the other keyboard or key range.

Abstract: In an electronic musical instrument, a plurality of component elements of a musical tone are designated by a respective plurality of manual setting elements and preset in a preset memory device. A person operating the device can select a musical tone to be produced based on the component element preset in the preset memory device or the component elements formed by the manual setting elements or any combination of such preset and manually set component elements. A visual display is used to display the amount of operation of the manual setting elements.

Abstract: A digital electronic organ mixture system comprises a pair of digital organs operatively connected in parallel to the same keyboard or keyboards. The keys are grouped into regions of adjacent keys. In one of the parallel organ systems, the frequency numbers ascend along the keyboard corresponding to the notes associated with the keys. In the other parallel organ system, the frequency numbers are weighted by preselected factors, the factor being the same for each keyboard region, and the factor for each successive region along the keyboard being lower than the factor for the immediately preceding region. Activation of a key along the keyboard produces a pitch series comprising a note produced by the unweighted frequency numbers in one organ system and a second note produced by the weighted frequency numbers in the other organ system. The pitch series breaks back at each successive keyboard region in accordance with the weighting factor for that region.

Abstract: The disclosure describes an improved electronic musical synthesizer capable of storing, recalling, editing and restoring signals representing different timbres of sound. During the editing process, indicating circuitry enables a performer to determine whether the control knobs of the synthesizer have been adjusted to the same settings which resulted in the signals originally stored.

Abstract: A sliding formant effect is produced in a tone generator of the type in which wave shape data points are sequentially and repetitively read out of a memory at a rate corresponding to the fundamental pitch of a musical tone. The formant effect is obtained by forming the sums or differences between consecutive data points for one waveshape period and storing the new data in memory in response to a formant control signal. Provision is made for advancing or retarding the effective formant cut-off frequency under command of the formant control signal.

Abstract: An electronic musical instrument of simple arrangement wherein a plurality of musical tones of different musical instrument types are preset; musical tones of a desired musical instrument type is first selected; musical tones belonging to the selected one of the plural musical instrument types are played by performance keys; the performance keys are concurrently used for selection of musical tones of the desired musical instrument type, and which comprises a changeover switch for determining the application of the performance keys for the original purpose or for selection of a desired musical instrument type, thereby eliminating the necessity of providing separate musical instrument type-selecting key or keys in addition to the performance keys.

Abstract: An entirely digital polyphonic musical synthesizer in which the amplitude of each spectral component may develop either linearly or logarithmically as a function of time, including amplitude computation means which produce, for each period of an amplitude clock signal, a new current amplitude value by linear or logarithmic interpolation between the initial current amplitude and a predetermined final amplitude value. The new current amplitude value is memorized in place of the initial value. When the current amplitude is equal to the final amplitude, a signal is transmitted to the synthesizer control means. The synthesizer enables gentle modulations in amplitude to be obtained and reduces the complexity of the instrument's control means.

Abstract: A tone source apparatus for an electronic musical instrument includes a sequentially addressable memory storing a plurality of waveform segment defining instructions, each instruction including a component representative of the amplitude variation, the time duration and the direction of change of the associated waveform segment. Output means comprising an adder-subtractor circuit and a latch is operated for accumulatively processing the stored amplitude variation representative components for producing a stepped output signal whose direction of slope is determined by the stored direction component. Control means interposed between the memory and the output means is selectively operable for modifying the stored amplitude variation components coupled to the output means for imparting a sinusoidal inflection to the stepped output signal.

Abstract: A keyboard operated electronic musical instrument in which a number of tone generators are assigned to actuated keyswitches. When a keyswitch is actuated, a tone generator is assigned with a musical waveshape selected from a library of waveshapes which are ordered in a predetermined arrangement. The assignment of waveshapes is made in a priority order according to the musical frequencies associated with the actuated keyswitches so that a chorus effect is obtained in which each note of a group of simultaneous notes has its own tone color. The assignment of waveshapes is made in an adaptive manner so that the melody line retains its own distinctive sound even when the number of notes played simultaneously on a keyboard changes. Vibrato effects can selectively be applied to any of the set of waveshapes.

Abstract: The present invention relates to economically fabricated means for the generation and processing, member selection, and acoustic radiation of pluralities of individual tone currents originating from at least one high frequency source and formed by note-information temporarily transferred through key depression, from permanent electronic memories to temporary memories in small numbers of standard tone units, in precise duplication of properties of pipe organ sound.There is described an electronic transfer organ for duplicating twenty-six known properties of pipe organ sound. The illustrative, inventive instrument employs completely standardized circuitry except for automatically programmable memories for each organ voice, which contain all the information required to form, switch and variously decouple all the notes in that voice.

Abstract: A digital waveform generating apparatus includes a key assignor selecting a frequency of a signal to be generated, a number-setting circuit for generating a first data word corresponding to the selected frequency, a first memory for storing said first data word, a second memory for storing a second data word, an accumulator for accumulating the first data word onto the second data word stored in the second memory, so that the second data word stored in the second memory after accumulating represents the sum of the second data word immediately prior thereto added with said first data word, a waveform memory, preferably an ROM, for storing predetermined waveform data and for generating a waveform data output signal, and a control circuit for controlling such accumulating and progressively addressing the waveform memory in accordance with the stored second data word at the time of a timing signal.

Abstract: In an electronic musical instrument of the type comprising a musical tone signal generator responsive to depression and release of a key of a keyboard for generating a musical tone signal, and a selector including a plurality of tone color selection switches for selectively imparting a tone color to the musical tone signal, there are provided a detection circuit to detect variation in states of the tone color selection switches for producing a detection signal, a tone generation inhibit signal generating means responsive to the detection signal for generating a tone generation inhibit signal having a predetermined duration, and a circuit responsive to the tone generation inhibit signal for preventing generation of a musical tone.

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.

Abstract: An electronic organ apparatus arranged to provide percussive musical tones by differentiating a rectangular waveform tone signal and subsequently clipping the differentiated signal at a variable level under the control of an envelope signal to produce an improved percussive sound envelope. The time constant of the differentiator may be varied to vary the output sound. The output sound may be controlled by concurrently varying the level of clipping of the differentiated tone signal and varying the time constant of the differentiator. Voicing filters and other modifying inputs may be utilized for further controlling the character of the output sound.

Abstract: In a control waveform generator for an electronic musical instrument of the type wherein the generator generates a control waveform adapted to control at least one of a tone pitch, a tone color and a tone volume, the control waveform generator is constituted by a pulse generator for generating a pulse signal having a repetitive frequency, and a detector including a counter which starts to count the number of the pulse signals when a key is depressed. The detector generates a first detection signal during an interval between depression of the key and a time at which a counter reaches a predetermined value and then produces a second detection signal until the depressed key is released.

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.

Abstract: In an electronic musical instrument which is arranged to produce musical tones belonging to the selected one of many different types of musical instruments and having a number of player-operable selection keys respectively corresponding to the number of types of musical instrument sounds desired, the improvement wherein means is provided for generating a sample tone belonging to that type of musical instrument specified by one of the above-mentioned selection keys at a prescribed pitch and period simply by depressing only once a particular selection key, without taking the trouble of successively depressing individual performance keys, thereby facilitating the selection of a desired type of musical instrument by the player.

Abstract: An electronic musical instrument generates musical tone signals by digitally executing the calculations of equations representing frequency modulation. The instrument comprises a keyboard information generating circuit for generating key information concerning depressed key numbers and key touch information concerning key operation, a plurality of system parameter generating circuits for providing parameter information in response to the outputs of a tone color selecting switch section, a plurality of system musical tone signal forming sections each for producing musical tone signals through the digital calculation of the FM equation in accordance with the abovementioned informations, and a musical tone generating section for producing musical tones by combining the musical tone signals provided by the musical tone signal forming sections, the musical tone signal forming sections calculating the FM equation by using different parameters provided by the parameter generating circuits.

Abstract: In a musical instrument having one or more tone generators in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced points defining the waveform of one cycle of an audio signal are transferred sequentially from a note register to a digital-to-analog converter in repetitive cycles at a rate proportional to the pitch of the tone being generated, apparatus is provided for varying the spectral content of the tone in response to control signals. A loudness control signal causes loud tones to be produced with a greater number of harmonics than those for a soft tone. A formant control signal also causes the tones to have a time variant spectral quality.

Abstract: In a musical instrument having one or more tone generators in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced points defining the waveform of one cycle of an audio signal are transferred sequentially from a note register to a digital-to-analog converter in repetitive cycles at a rate proportional to the pitch of the tone being generated, apparatus is provided for varying the spectral content of the tones in response to a loudness control signal. Loud tones are produced with a greater number of harmonics than those for a soft tone.

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.

Abstract: A divider keyer circuit arrangement for a synthesis organ utilizing four integrated circuit chips to generate the notes for a 61 key manual with 9 harmonic drawbacks or tabs. On-chip cross wiring and the use of clock lines for synchronization pulses and other design techniques enable the use of four identical integrated circuit chips in standard 40 pin packages to be used to generate the full complement of notes for a 61 note keyboard.

Abstract: The musical instrument is of a waveform memory device read out type and comprises a frequency information generator for generating a plurality of sets of frequency informations each set consisting of a subplurality of frequency informations and corresponding to each of the tone pitches of the depressed keys in a keyboard, a selector for selecting one, at a time and one after another, of the subplurality of frequency informations generated by the frequency information generator for each one key depressed, an accumulator for repeatedly accumulating the frequency information selected by the selector to produce an increasing accumulated value, a waveform memory device for storing the amplitude values at successive sampling points in one period of a sine wave utilized to form a desired musical waveform, a comparator for comparing the accumulated value with a preset value and controlling the selecting operation of the selector during the operation of the accumulator.

Abstract: In an electronic musical instrument, a tone source circuit provides tone signals of audio frequencies representing respective notes in a musical scale. A keyboard circuit provides a keying sequence pulses each existing at such a time slot of time sharing at an ultra-audible rate as is assigned to each of keys being depressed. The tone signals and the respectively corresponding keying sequence pulses are AND-gated respectively and then OR-gated commonly to produce a combined tone signal. The keying sequence pulses are obtained by sequentially scanning all the keys in the keyboard in one sequence, or may be equivalently obtained by scanning the same named keys in different octaves simultaneously and AND-gating with octave representing pulses. Or the octave representing pulses may be omitted by separately processing tone signals octave by octave. The system is suitable for digitalization and for production in IC configuration.