Abstract: Tonality designation of an electronic keyboard instrument is realized by utilizing keys instead of conventional tonality designation switches provided on the panel of its.The tonality designation system comprises a tonality data forming circuit and a memory. The tonality data forming circuit generates tonality data consisting of keynote data and scale data representative of key note and type of scale respectively based on key depression and transfers it to the memory in advance before performance. The memory stores the tonality designation data during performance. A musical tone to be produced is formed or controlled based on the stored tonality data and a depressed key.

Abstract: In an electronic musical instrument, there are provided a main musical tone generator for producing a main musical tone and a submusical tone generator for producing a submusical tone different from the main musical tone. The main musical tone generator has a plurality of tone production channels smaller than a total number of keys, the assignment of key information data corresponding to a depressed key to the tone production channel is changed according to a performance mode. The tone production channels and the key information data corresponding to depressed keys are divided into at least two groups respectively in the case of performance mode. One group of the tone production channels is assigned to one group of the tone production channels to produce the main musical tone for an automatic accompaniment, whereas another group of the key information data is assigned to the remaining group to produce the main musical tone for melody.

Abstract: A circuit for producing musical tones is disclosed which includes a keyboard for selecting the musical tones, and a tone generator responsive to the keyboard for generating a square wave signal having the frequency of the musical note to be generated. A charging circuit is provided for charging a capacitor to a predetermined level of voltage when the square wave signal is terminated, and for exponentially discharging the capacitor when the square wave signal is initiated. A modulation circuit amplitude modulates the square wave signal in proportion to the capacitor voltage to produce an exponentially decaying signal which simulates the waveform produced by a struck piano string. A speaker is also included to convert the exponentially decaying signal into audible musical tones having the sound of piano notes. The circuit of the invention requires only a small number of components, making it suitable for use in miniature musical toys.

Abstract: A harmony generator for an electronic organ, wherein the identity of played keys of the keyboard(s) is read into a storage device and then operated upon by a data processing device such as a microcomputer, so as to supplement the played note data with additional data designating "fill-in" notes which are to be sounded in addition to those actually played. The data contained in the storage device, as supplemented, is then used to control the transmission of tone generator signals to the audio output system of the organ. In a preferred embodiment of the invention, the criteria used to select fill-in notes cause notes corresponding to the nomenclatures of played notes of the accompaniment keyboard to be sounded as though played in the octave below the lowest note played on the solo keyboard. Other fill-in criteria are also contemplated. The fill-in notes are generated by combining played accompaniment data with masks.

Abstract: An electronic musical instrument of a polyphonic type comprises, first tone generating means capable of producing, in a first musical tone property, a plurality of musical tones respectively corresponding to a plurality of depressed keys, and further comprises second tone generating means capable of producing, in a second musical tone property, a musical tone corresponding to a specific key selected from said depressed keys in accordance with a predetermined standard of selection. The first musical tone property is set to be suitable for ensemble performance, whereas the second musical tone property is set to be suitable for solo performance. Among the musical tones produced by the first tone generating means, the one corresponding to the specific key is made less prominent than the ones corresponding to the other depressed keys.

Abstract: A root note detection circuit detects the highest or lowest key among depressed keys in an accompaniment key range as a root note designation key. A root note memory stores the detected root note data and rewrites its storage each time the detected root note data changes. A chord type detection circuit detects a chord type in accordance with states of depression of keys other than the detected root note designation key in the accompaniment key range. The detected chord type data is stored in a chord type memory by being controlled by outputs of a root note change memory and a new key detection circuit. The root note change memory detects change in the root note by comparing the output of the root note detection circuit with the output of the root note memory and outputs a root note change signal during a preset waiting timing. Accordingly, the data stored in the chord type memory can be rewritten not only upon detection of depression of a new key but during this waiting time.

Abstract: An electronic organ having a scanned keyboard manual (10) includes a keyboard latch (24) interposed between the scanning apparatus (12) and the organ keyers (26). The keyboard latch (24) comprises a gate (42) for comparing the serial data pulses, each of which represents a respective depressed key, produced at the output of the scanning apparatus (12) during each scan of the keyboard manual (10) with the serial data pulses produced during the immediately preceding scan for developing a control signal representing the detection of a depressed keyboard key during the on-going scan which was not depressed during the immediately preceding scan. An output circuit (52, 54, 56) is provided for continuously developing an output signal reflecting the keys depressed during the last scan in which a control signal was developed whereby the tone signals corresponding thereto are continuously sounded even though the keys have subsequently been released.

Abstract: An electronic musical instrument in which a single manual keyboard is provided with two voicing blocks which has a certain keyboard space interval therebetween and at least one of which generates a multiple tone corresponding to keys being depressed. There is provided a circuit for providing a certain time interval from a time-divided signal produced by the key depression. This circuit distinguishes between tones from the two voicing blocks, to thereby separate them from each other. There is also a circuit for generating a monophonic or polyphonic tone signal from each of the separated time-divided signals.

Abstract: The tone production system for an electronic musical instrument comprises depressed key detection means for outputting pulses at a timing corresponding to a key depressed by time division timings assigned to each note, a shift register for shifting successively said pulses outputted from said depressed key detecting means in synchronism with said time division timing, key data forming means for taking out each output pulse of predetermined plural stages of said shift register in accordance with a desired type of chord, musical tone production means for producing each of plural musical tone signals of notes corresponding to pulse generation timings in accordance with each pulse taken out by said key data forming means.

Abstract: A chord generating apparatus of an electronic musical instrument is provided with a selector which selects a single key among a plurality of depressed keys, a detector for detecting a chord type according to types of keys other than the selected key, and a musical tone signal forming circuit for forming a musical tone regarding a chord determined in accordance with outputs of the selector and detector.

Abstract: This electronic musical instrument comprises means for selecting one of a plurality of performance modes and musical tone production means having tone production channels less than the number of keys. Tones are produced through said channels based on the time division multiplex key data which are set according to the depressed status of all key in the different manner according to the selected performance mode of the mode selecting means.

Abstract: An electronic organ, particularly of the institutional type employing classical voicing, having Swell and Great manuals as well as a full pedalboard wherein the manuals and pedalboard are multiplexed simultaneously to produce a plurality of synchronized serial data streams. Intermanual coupling is accomplished by connecting the data stream from one manual to the footage generation cirlcuit of another manual, and footages are generated for each manual by utilizing tapped shift registers introducing controlled amounts of delay of the keyboard data before demultiplexing thereof. There is a bank of demultiplexer-keyers for each voice, such as flutes, principals, complex and percussion, which receive the serial data streams from one or more of the footage generators. The demultiplexer-keyers are supplied with tones and function to demultiplex the serial data streams and provide to the voicing circuitry tones selected in accordance with the keydown pulses in the serial data streams.

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: An electronic musical instrument forms output signals having at least one frequency component and an amplitude defining envelope. Output signals are formed for selected string simulators on the instrument so that the notes and chords may be formed simulating a stringed musical instrument by combining the output signals. Various parameters of the amplitude envelope of the output signals may be varied at a user's selection.

Abstract: A keyboard operated musical instrument is disclosed having a portamento effect controlled from a portamento keyboard consisting of a linear array of keyswitches. The keyswitches are arranged in groups corresponding to each musical note and spaced so that a number of contiguous switches are actuated by each finger in contact with the portamento keyboard. Apparatus is provided for generating a frequency number corresponding to the closest switch actuated by the center of each finger thereby providing polyphonic portamento effects as the finger positions are slid along the portamento keyboard. An ADSR generator is used to provide envelope modulations initiated when a new finger has been detected on the slide wire and when a finger has been removed. A priority logic using frequency differences is used to distinguish between new fingers or the changes in position of a finger already in contact with the slide wire.

Abstract: A preferential circuit for an electronic musical instrument is provided in which a memory circuit is employed to memorize a key data signal corresponding to the last depressed key and at least one key data signal corresponding to the second last depressed key. To drive a tone generator, the memory circuit normally outputs the key data signal of the last depressed key but outputs the signal of the second last depressed key when the last depressed key is released with the second last depressed key being held depressed. If the player depresses an errouneous key and release this last depressed error key, a musical tone corresponding to the second last depressed key is then produced.

Abstract: A polyphonic, keyboard-type electronic musical instrument capable of automatic production, in response to key depressions on upper and lower keyboards, of "fill notes" which bear the same note names as the depressed lower keys but which, preferably, fall within an octave below the lowest pressed upper key at every moment. The instrument is of the type wherein each depressed key is coded into key data in accordance with a binary "key code" composed of a note code and an octave code. The note code identifies the note name of each key, whereas the octave code identifies the octave to which the key belongs. Upon depression of a key on each of the upper and lower keyboards, the note-coded data derived from the key date representative of the depressed lower key are combined with the octave-coded data derived from the key data representative of the depressed upper key if the note name of the depressed lower key is below that of the depressed upper key.

Abstract: An electronic musical instrument having a plurality of keys is provided with a depressed key detector which detects depressed keys and produces key identifying signals; a highest signal detector which detects a highest one among the key identifying signals having a highest priority in accordance with a predetermined order of priority; a musical tone producing unit responsive to the detected highest signal for producing a musical tone of a tone pitch corresponding to the highest signal; a reference memory device for storing the detected highest signal in accordance with a predetermined condition; and a controller for inhibiting the musical tone producing unit from producing the musical tone according to a relationship between the detected highest signal and an output of the reference memory device.Thus the progression of simultaneous plural key depressions provides a melody performance including rests.

Abstract: An electronic organ includes a plurality of buffers for receiving solo keyswitch status information, accompaniment keyswitch status without octave information, and depressed keyswitch status from an arpeggio keyboard. A scan circuit and a microprocessor gate the buffers into an input memory which retains an image of the solo, accompaniment, and arpeggio keyboards. A control program, stored in ROM, is responsive to the input memory, shared registers, and harmony switches actuable in several modes, to produce one or plural harmony notes in either open or closed harmony, and to assign different note names to the actuated keyswitches on the arpeggio keyboard. The resulting harmony and arpeggio notes are stored in an output memory and are transferred to a transistor matrix which activates solo keyers to produce harmony and arpeggio notes with solo voicing. A rhythmic harmony modulator is actuable to modulate the harmony notes in a rhythmic pattern of individual and delayed beats.

Abstract: A high note data generator for use in electronic musical instruments such as electronic organs, pianos, and the like, wherein the time division multiplexed serial data stream is received, and a single data pulse is generated in the time slot of the first occurring pulse in the data stream. In organs wherein the manual is scanned from high to low, this will be the highest note played, which is convenient from the standpoint of converting polyphonic data to monophonic data for certain organ voicing or for use in solo manual fill note generation. Alternatively, the system can be utilized for converting a pulse spanning more than one time slot into a pulse occupying only a single time slot, which is coincident with the leading edge of the first-mentioned pulse. The system comprises a first latch having its clocking input connected to the serial data stream and one of its outputs connected to an input of an AND gate.

Abstract: An electronic musical instrument having its keyboard divided into plural key ranges with musical tones being generated with tone colors which are different one key range from another. For achieving this object, the instrument comprises channel processors, tone generators, additional tone generators for the lowest (or highest) key in each key range, a common key coder for obtaining key data of depressed keys and a control circuit for supplying key codes delivered out of the key coder to only a channel processor of a corresponding key range. The key coder delivers out key data of depressed keys sequentially one key data at one time slot. According to the invention, the lowest (or highest) tone in a predetermined key range is generated with a tone color corresponding to the key range and also with a different tone color.

Abstract: In an electrical keyboard musical instrument apparatus is provided for automatically selecting one of a library of chord types which is closest to a chord played on the instrument. The closest decision is made by processing the actuated keyswitch data by a set of matched filters each of which corresponds to a member of the library of chord types. The chord type decision is made to correspond to the matched filter producing the maximum output response. The selection between chord types yielding equal responses is resolved by priority logic based upon the frequency of chord usage. A root note is chosen for each selected chord type.

Abstract: An envelope signal generator which has a key depression/release signal generator for producing different output levels in response to key depression and key release, a switching circuit which is set to a first output level upon key depression and set to a second output level when the stored output level of an analog memory has reached a certain value, a preset circuit for outputting at least a level setting voltage and first and second time constant setting voltages relating to an envelope, a priority selector which is supplied with the key depression/release signal generator output, the switching circuit output and the level setting voltage and selects them in a predetermined order of priority, a first circuit for converting into a current the output from a voltage controlled amplifier supplied with the analog memory output and controlled by the first time constant setting voltage, a second circuit for converting into a current the output from a voltage controlled amplifier supplied with the analog memory ou

Abstract: A key assignor for electronic musical instruments which has a keyboard multiplexer including a memory for temporarily storing the state of key depression on a keyboard, a key priority circuit group operating to output only key information of top priority while inhibiting the other key information outputs in accordance with priority of keys of the keyboard and to output key information of the next priority after being reset, and a multiplex code generator for generating the key code corresponding to the key being depressed, a channel assignor for giving priority to channels to assign thereto the key code from the keyboard multiplexer, and a key code memory for storing the key code from the keyboard multiplexer based on a channel assign signal generated from the channel assignor.

Abstract: An electronic musical instrument is of a type wherein a key depression brings forth the generation of a key code identifying the depressed key in a digital representation, and the key code designates the tone to be produced. Based on the single key code of the depressed key, there are produced plural key codes indicating plural tones which are in predetermined musical interval relation with the depressed key to constitude a chord. The original key code and the produced key codes are utilized one after another successively to perform an automatic arpeggio.

Abstract: An electronic musical instrument is of a type in which a particular note tone and tones corresponding to the remaining notes among depressed keys are alternately and repeatedly produced in accordance with tone production timing signals having a predetermined period. The tone production timing signals are produced by frequency dividing tempo pulses generated from a tempo pulse oscillator. An alternate production control is conducted by gating alternately signal of the particular note tone and signals of other tones and delivering to a sound system. The period of the tone production timing signals can be controlled by a circuit which detects depression of plural keys.

Abstract: An automatic rhythm system for an electronic organ adapted to enable a plurality of percussive instruments and a plurality of accompaniment and "Walking Bass" instruments normally played by the pedals of the organ includes two separate rhythm pattern generators each storing a plurality of rhythm patterns, the outputs from one of which enables selected percussive instruments and the outputs from the other enabling little used percussive instruments and the "Walking Bass" normally played by the pedals. A plurality of rhythm select switches are directly connected to respective input terminals of the first rhythm pattern generator, and to ensure against generation of musically unacceptable combinations of rhythm patterns when a combination of rhythm patterns is selected, the rhythm select switches are connected through control logic to the second rhythm pattern generator, the control causing the second rhythm pattern generator to play only the first turned on rhythm pattern of a combination of patterns.

Abstract: An electronic musical instrument of a key code processing type includes a single tone generating section for producing a solo performance effect without providing a solo performance keyboard. This single tone generating section comprises a single data selection circuit which selects the highest (or lowest) note from among notes of depressed keys for producing a single musical tone. The single data selection circuit includes first and second memories and a comparison circuit. An input key code A is compared with a key code X stored in the second memory and the input key code A is stored in the first memory if the value of the input key code A is greater than the value of the key code X. When one cycle of the above described comparison has been completed, the data stored in the second memory is rewritten with the data of the first memory. The key code for the highest note is now stored in the second memory to designate a tone signal to be produced for a solo performance.

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.

Abstract: The circuit enables the selection of the upper or the lower tone of an electronic organ chord with regard to a switching signal. In response to said switching signal each tone frequency signal handled is either fed to the anode or the cathode of a switch component of a plurality of switch components connected in series whereas the switch components of the tone frequency signal not handled are switched on.

Abstract: An electronic musical instrument is provided with a plurality of wave shape memories storing different musical tone wave shapes of different memory sizes for different tone ranges. The memory for the treble tone is of a small size and that for the bass tone is of a large large size. When a key is operated in the keyboard, a memory corresponding to the tone range to which the operated key belongs is selected and read out. While successfully avoiding economically disadvantageous increase in the memory size of the wave shape memories, beautiful and clear musical tones can be obtained having different tone colors for different tonal pitches just like those generated by natural musical instruments.

Abstract: A brass keyer system for an electronic organ wherein the keyboard is multiplexed to produce a polyphonic serial data stream, which is then converted to a monophonic serial data stream containing a keydown signal in a time slot corresponding to the highest note played on the keyboard. The monophonic data stream is converted to a multiple bit binary word that is used by the tone generation and keying portion of the system to produce a rectangular wave tone corresponding in frequency to the highest depressed key and having amplitude and pulse width modulation on attack and decay so as to produce a brass tone. The monophonic serial data stream is demultiplexed by means of a recirculating delay loop which repetitively recirculates the keydown pulse for the depressed key. The number of recirculations of this pulse are counted by a first counter and the position of the pulse within the delay loop is registered by a second counter, which is synchronized with the multiplexer.

Abstract: A monophonic electronic musical instrument comprises a single key preferential selection device. Key switches are connected in a matrix fashion between the group lines and the individual lines. The group lines are sequentially and repetitively scanned to detect the first one in the sequence of the groups where any key switch is closed, and the individual lines to which any closed key is connected deliver key detection signals, which in turn are introduced into a preference circuit to select the key detection signal of the highest priority. The group detection and the individual detection co-operatively designate a single key for tone production.

Abstract: An electronic musical instrument includes a tone signal generator whose operation is controlled by active electronic signal processing. The instrument includes both tone effect control means to provide an alternating current control signal to the tone signal generator and manually operable tone frequency control means having selectively variable resistance and selectively variable capacitance characteristics, with one of these characteristics being variable among logarithmically spaced increments and the other characteristic being variable among linearly spaced increments.

Abstract: A limited number of top octave synthesizer tone generating circuits for producing various tones are used in an electronic organ. Each of the top octave synthesizer circuits is capable of producing any tone which can be produced by the organ. An assignment circuit is employed to assign different ones of the top octave synthesizers to produce the tones represented by different key closures. Because of the limited number of tone generator circuits employed, it is possible under some circumstances to attempt to cause the organ system to produce root tone outputs in excess of the number of top octave synthesizer circuits used in the system. When this occurs, a root tone for a new note is assigned to the top octave synthesizer circuit which is farthest into its decay mode of operation, thereby terminating the tone previously produced by that top octave synthesizer circuit earlier than would be the case if the full decay of that tone were permitted to take place.

Abstract: In a key code generator which has key code generator circuits, each corresponding to one of a plurality of key switches and composed of a memory circuit for storing the status of the key switch with a master clock pulse, a circuit for detecting the status change of the key switch to its depressed or release state, means for deriving a key code from the outputs of the memory circuit and the detecting circuit, means for producing a latch pulse from the master clock pulse and the key code and means for completing the output generation with the master clock pulse, a circuit for determining priority of the key code generator circuits, and a control circuit for giving priority to key release over key depression when key switches are simultaneously released and depressed, respectively, there is provided a time-division device which comprises a key switch (m.times.

Abstract: This invention relates to tone generating systems for polyphonic electronic musical instruments. The system includes a plurality of programmable tone generators each of which is assigned to a different note to be sounded. For a preferred embodiment, one of the programmable tone generators is designated as a solo high tone generator, and is always utilized to produce the highest note to be sounded. Another generator may be designated as the solo low generator, and will always be utilized to generate the lowest note to be sounded. Additional solo note generators may be provided if desired. Tone generators are interconnected in a priority scheme with one generator at a time being designated as the next generator to be assigned a note to be sounded, and the designation being advanced in a predetermined manner as notes are assigned successively to the generators.

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: 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.

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.

Abstract: An automatic accompaniment apparatus in an electronic organ having a keyboard for melody provided with a plurality of key switches for accompaniment, respective ends of the key switches being connected to a voltage generating circuit and respective opposite ends of the key switches being connected to a chord gate circuit through memory circuits. A key selection circuit for selecting a key of music is provided so that a rhythm accompaniment tone corresponding to a melody is obtained as an output signal from the chord gate circuit. A rhythm pulse is generated from a rhythm pulse generator. Connected between the key switches and the voltage generating circuit is a switch element and a keying pulse generator connected to the switch element.

Abstract: An organ circuit and method of operation in which a detecting system detects combinations of keys played in the accompaniment portion of the keyboard arrangement of an electronic organ and through associated circuitry causes a respective chord to sound regardless of the particular position of the depressed keys or the particular chord inversion represented by the depressed keys.

Abstract: Keyboard apparatus for an electronic musical instrument in which a particular code is assigned to each of keys of the keyboard and which is provided with a multiplexer circuit for detecting the depression of the key corresponding to an input code, means for sequentially generating the codes of the keys, memory means for storing the codes, a comparator circuit for comparing the outputs from the memory means and the code generating means to provide a coincidence signal when the both outputs are coincident with each other, a cycle control circuit for controlling a key ON cycle and a key OFF cycle in distinction from each other, and gate means for selecting the output code from the code generating means and the code of the memory means with the key ON cycle and the key OFF cycle to output to the multiplexer circuit. In the key ON cycle, the multiplexer circuit detects that the key having not been depressed yet is newly depressed, and stores it in the memory means.

Abstract: A key assignor comprising a scanning means, a first clock memory, a second memory for releasing a switch information, a comparator, a priority circuit device, a means for inhibiting the write-in operation, and a means for extracting key codes. Key switches are divided into blocks to scan the latter without scanning all of key switches. Scanning time can considerably be reduced as compared to prior arts, thereby enhancing response greatly.

Abstract: A key code generator for electronic musical instruments which has a switch matrix circuit having a plurality of switches disposed at the intersections of two sets of buses, means for simultaneously applying signals to the switch matrix circuit from one of the two sets of buses to derive outputs from a plurality of blocks into which the buses of the other set are divided line by line, a memory for detecting the blocks that even one switch is in the on state from the bus outputs of the switch matrix circuit and temporarily storing signals of the detected blocks, a first priority selector for selecting block signals in a predetermined order of priority from the bus outputs and sequentially outputting the block signals with a predetermined clock pulse, means for inhibiting the block detecting operation during outputting from the first priority selector and applying the selected block signals to the buses of the detected blocks to sequentially scan only the detected blocks, a second priority selector for selecting

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.

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. One form of the system combines time multiplexed keying with priority coupling of the keying information to a plurality of voltage controlled oscillators through sample-and-hold memory circuits. Each oscillator has its own tone voicing circuits. In another preferred all-digital embodiment, the time division multiplex digital logic signals representative of the played keys are applied instead to a memory circuit and a comparator circuit.

Abstract: An arpeggio circuit for an electronic organ employing digital encoding, decoding and code conversion techniques to semiautomatically generate an arpeggio effect composed of tone signals having an octaval relationship and corresponding to selected note keys held down on an accompaniment keyboard. The rate of generation and order of the arpeggio tone signals is controlled by means of a plurality of manually actuatable arpeggio control switches. A plurality of individually identifiable control signals are sequentially generated in response to sequential actuation of the plurality of control switches. The control signals are binarily encoded. Tone signals provided by a set of tone generators are selectively associated with appropriate ones of the encoded control signals by a tone selector circuit which provides the selected one of the tone signals to an arpeggio output tone signal generating circuit when the associated encoded control signal is being generated.

Abstract: An automatic chord generating circuit for a digital polyphonic tone synthesizer having one or more keyboards. Key operated switches are connected in groups corresponding to the notes in an octave. A signal source is selectively connected by the closed switches of each group in sequence to associated ones of a plurality of signal lines. A priority circuit selectively connects a signal from only one line at a time to a corresponding one of a plurality of output lines, so that operation of more than one key in an octave produces only one output signal at a time. A switching logic circuit, responsive to digitally coded input signals identifying any one of a plurality of different chords, connects the single output signal from the priority circuit to additional ones of the output lines for activating multiple notes within the octave.

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.