Abstract: A fill note generator for use in electronic musical instruments such as electronic organs which include a keyboard having a solo portion customarily played by the right hand and an accompaniment portion customarily played by the left hand, and wherein the respective solo and accompaniment portions may be on separate manuals or on a single manual. A multiplexer scans the keys of the solo portion of the keyboard and generates a time division multiplexed solo data stream having keydown signals in discrete time slots for each actuated key of the solo portion of the keyboard. The keys of the accompaniment portion of the keyboard are interconnected so as to form twelve sets corresponding to the twelve pitches of the chromatic scale wherein the keys in each set are connected to a common output.

Abstract: An apparatus for reproducing sound from data which are electrically stored in an electronic memory is disclosed. This sound reproducing apparatus includes a member for providing timing control to associated electronic circuitry. There is also a member for retrieving the individual elements of the data from the memory and electronic components for converting the retrieved elements into respective audio signals. Furthermore, there are electrical circuit elements for audibly broadcasting the respective audio signals. The duration of the broadcasting of each respective signal is controlled by a circuit which is responsive to the timing control member and the retrieved elements. The present invention may also broadcast sounds from externally input signals. This is effected through an external source element for obtaining such external input and a switch means for connecting either the stored elements retrieved from the memory or the external input from the external source to the audible broadcasting member.

Abstract: In an electrical tone generator apparatus is provided for automatically selecting one of a library of chord types which is closest to a chord fingered on a fretted string instrument. The closest decision is made by processing the fingered fret input 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 chord type. Note keying data is generated from the selected chord types which is transposed to the correct musical pitches in response to the chosen root note. The note keying data is grated by an automatic rhythm generator and the output is used to actuate electronic musical tone generators.

Abstract: An electronic musical keyboard instrument that is controlled by a digital processor. Key and stops/effects statuses are sampled, during successive time intervals, and read into random access memory associated with the digital processor. After manipulation and/or supplementation of the status information to effect implementation of various features, key-representative signals are read out to tone generation and voicing circuits.

Abstract: Electronic and logic circuitry for an automatic tonal bass rhythm accompaniment feature and an automatic chord feature in an electronic organ. Automatic bass rhythm accompaniment produces a pattern of notes based upon a tonic note selected by the instrumentalist such that the desired musical effect is produced when the pattern of notes is combined with the notes being played by the instrumentalist. The electronic organ has stored in a memory various rhythm patterns which can be selected by the instrumentalist by closing rhythm switches. Electronic circuitry then causes notes for the selected rhythm pattern or patterns to be played automatically in response to the actuation of a pedal switch or keyswitch. The automatic chord feature of the present invention provides selectively major triad and dominant seventh chords or minor triad and diminished seventh chords automatically in response to the selection of a root note by the instrumentalist.

Abstract: An expression means has been developed which can accentuate only a selected musical sound, e.g., melody, out of melody, accompaniment chord and bass sound generated in an electronic musical instrument and does not accentuate other sounds. The expression means of the present invention produces a first electric potential that will vary in response to an operation of an expression pedal and a second potential that will vary in response to a slow operation of the expression pedal though irresponsive to a quick operation of it. For gain control of amplifiers that deal with musical sounds required to be accentuated, said first potential is prepared, and for gain control of other amplifiers that deal with musical sounds free from accentuation, said second potential is prepared. Furthermore, the expression means of this invention employs changeover switches to realize arbitrary choice of the sounds to be accentuated.

Abstract: A microcomputer based synthesizer having a digital keyboard, digital envelope generators, voltage controlled amplifiers and filters, and numerous potentiometer type presets is disclosed. The presets are scanned by the microcomputer, converted to digital form, stored for recall on demand in a non-volatile memory, converted to exponential form by use of a look-up table when required, and output to clamp-and-hold circuits associated with each voltage controlled circuit. Each preset sample and hold operation is followed by a scan of the keyboard to minimize the impact of the capture system on the keyboard scanning rate.

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 electronic musical instrument with an automatic chord performance device is of a type in which chord tones of plural series of different tone colors in different rhythm patterns are produced. This instrument employs a memory for storing a plurality of patterns per one rhythm and for plural rhythms in order to simultaneously obtain the chord tones of plural series per one rhythm. The patterns are read from the memory as tone generation timing signals. These tone generation timing signals control the amplitudes of the envelopes of the chord tone signals. The chord tone signals thus controlled in amplitude are generated after being controlled in the tone color in each of the series.

Abstract: An electronic musical instrument which is provided with a note frequency data memory for storing note frequency data corresponding to data of key switch depression through a key code register, a note frequency data register for latching and storing the data from the note frequency data memory by a time division pulse from a time division control signal generator, an octave data register for latching and storing octave data from the key code register by the time division pulse from the time division control signal generator, a frequency generator composed of a programmable counter supplied with the output from the note frequency data register to provide a frequency corresponding thereto, a frequency divider array supplied with the frequency and a decoder supplied with the output from the octave data register, the outputs from the respective output ends of the frequency divider array being selected by the output from the decoder in accordance with the octave data, and a musical waveform generator composed of fi

Abstract: An arpeggio system, utilizing bipolar digital logic devices in all control and sequencing functions, generates a variety of arpeggio and strum note patterns. A key operated switch enables a NOR logic note gate, or a series of octavely related note gates, and activates a system clock which causes a pulse to be transmitted along a chain of shift registers, one of which corresponds to each note of the organ. If a given note gate has been enabled when its corresponding shift register is pulsed, the note gate is triggered. When a note gate is triggered, the system clock pauses for a preselected interval allowing the signal from a corresponding tone generator to be sounded through an appropriate system of filters and amplifiers. The system clock can cause the shift registers to scan in the up, down, or up and then down directions. An octave priming device can permit the sounding of notes in higher octaves which correspond to notes actually played.

Abstract: The disclosure describes improved apparatus for sampling a digitally-stored waveshape only at a rate 2.sup.N times the fundamental frequency of a note synthesized, where N is an integer. The apparatus includes a digital memory for storing a digital representation of the waveshape. A top octave synthesizer produces clock pulses at a rate 2.sup.N times the fundamental frequency of a desired note. An octave oscillator generates addresses for the digital memory in response to at least some of the clock pulses depending on the octave in which the desired note is located. A digital-to-analog converter converts the output from the digital memory into an analog signal suitable for sound production.

Abstract: An electronic musical instrument is of a channel assignment type and simultaneously produces a plurality of tones in automatic arpeggio performance. For that purpose, the instrument incorporates a plurality of automatic arpeggio performance channels. An automatic arpeggio performance is carried out in accordance with an arpeggio pattern. In order to simultaneously produce a plurality of automatic arpeggio tones, the instrument assigns respective arpeggio composing tones for the plural arpeggio performance channels by using an arpeggio pattern for one-tone production and a change pattern obtained by adding change information to the arpeggio pattern. Thus an automatic performance of polyphonic arpeggio is realized.

Abstract: A harmony authorization detector (HAD) synthesizer electronically generates single audible musical notes in harmony with single original aural notes of a melody as the melody is played on an instrument by a single player. Thus the HAD functions as, in effect, a second instrument electronically operational in harmony with a manually played lead instrument. The HAD synthesizer is particularly useful with guitars although not so limited. When a lead electronic guitar is used in a solo situation playing one original note at a time, the HAD synthesizer will, for each string on each position of the guitar and with the aid of a group of tone decoders, electronically detect the single fundamental note played by the guitarist and will authorize the emission of a preset, predetermined electronically generated synthesized single harmony note e.g. a third, fifth, seventh, etc. based on the fundamental of the single note played by the lead guitarist.

Abstract: An accompaniment system for an electronic musical instrument is selectively actuatable for producing accompaniment effects such as arpeggio in accordance with selectable notes or chords and with selectable rhythm patterns. The electronic musical instrument includes one or more conventional keyboards, a set of chord switches for selecting one of a plurality of predetermined chords and a set of rhythm switches for selecting one of a plurality of predetermined rhythm patterns, respectively. The accompaniment system includes a ROM containing note position signals arranged in a plurality of groups, each group corresponding to one of the selectable rhythm patterns. An electronic circuit selects one of the groups in response to activation of one of the rhythm pattern selector switches and sequentially combines each note position signal in the group with a chord displacement signal developed in response to actuation of one of the keyboard notes or chord selection switches.

Abstract: An electronic clock with a chime system has exclusively electronic processing for production of a variety of tone signal sequences consisting of known melodies or portions thereof and time-identifying sequences of strokes. The characteristic values of these tone signal sequences are loaded into a ROM memory and can be recalled, as required, by electronic control and release circuits at each quarter, half, three quarter or full hour. The amplitude of the audio output signals is automatically controlled in accordance with the time of day.

Abstract: A complementer for floating point binary numbers utilizes two digital logic decision rules selected by the value of the power of the input number. The first decision rule is selected for an input power of -1 and constructs a power and mantissa determined by the binary sequence form of the input mantissa. The second decision rule is selected for input powers less than -1 and constructs a mantissa determined by the binary sequence form of the input mantissa and the value of the power. The complemented power is set to a -1 value. The complementer is advantageously employed in digital electronic musical instruments.

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 electrophonic musical instrument which can be of sufficiently small size to be incorporated in a portable electronic timepiece, having operating members which serve to input data corresponding to pitch and timing information for a sequence of musical notes to be stored in an internal memory, and having means whereby said sequence of musical notes can be subsequently automatically reproduced audibly by actuating another operating member.

Abstract: An electronic musical instrument having an automatic performance device includes a memory storing in addition to automatic performance data, envelope control data for controlling envelopes of automatic performance tones to be generated. The envelope control data has two logical values and is used for controlling the envelope of the tone at the decaying portion. The value "0" designates a gradual decay and the value "1" designates a quick decay. The automatic performance tones are respectively imparted with either of the gradual and the quick decay shapes suitable for the time intervals between the generated tones in the designated automatic performance pattern.

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: A rhythm generator which is provided with a plurality of rhythm pattern memories, each storing one rhythm pattern and outputting the rhythm pattern in response to a rhythm clock, a bar counter for counting the number of bars with the rhythm clock, and means supplied with the output from the bar counter to selectively assign desired ones of the rhythm pattern memories one after another for a desired number of bars.

Abstract: In a modular, expandable organ system comprising a plurality of large scale integrated circuit (LSI) chips an LSI chip is provided which produces chord and bass frequency generation and identification. It automatically coordinates with another chip in rhythm production. It incorporates frequency generators, identifies a chord played, and provides keyers for chord notes.

Abstract: A register arrangement for electronic organs wherein the programs which are stored in data storages of distributor circuits on one insertable card can be transferred into the storages of distributor circuits on another insertable card. The one card can be programmed by hand by way of register switches. The storages of distributor circuits on the other card retain the programs upon detachment of the other card so that the latter can be transferred into the register arrangement of another organ.

Abstract: A device for producing a plurality of musical tones comprises a programmed rectangular wave generator that produces a series of rectangular waves of the same amplitude for each tone. Each wave in each of the series of waves has a predetermined energy content and drives a speaker or other sound producing transducer such that the musical tone produced has the same aural qualities as that produced by a musical instrument. In the preferred embodiment the wave generator is a programmed integrated circuit microcomputer having a Read Only Memory in which are stored the sequence of notes of one or more musical compositions that are played under program control. The device is particularly adapted to produce bell tones having minimum harmonic distortion which, in combination with microminiature speakers and lights in bell shaped translucent housings and driven by the series of rectangular waves, becomes an attractive Christmas decoration that plays a number of traditional Christmas carols.

Abstract: An electronic musical instrument of a digital processing type comprises a first ROM storing frequency information corresponding to respective notes for producing tones with pitches of the equally tempered scale, a second ROM storing correction data for the frequency information to shift the pitch to bring to just intonation relationship, a chord detector for identifying the root note, and a pitch adjusting circuit for modifying the frequency information of the chord constituent notes other than the root note in accordance with the correction data read out from the second ROM.Thus the tones are produced in just intonation relationship when they constitute a chord and otherwise in a normal equally tempered scale.

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 reference 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 for loading a new set of data words in the note register without interrupting the transfer of data words from the note register to the converter is provided. The note register is divided into two sections. One section is loaded with data words defining half a cycle of an audio signal. By taking advantage of half cycle symmetry of the waveform, the other half of the note register is loaded at the same time using the same data words in reverse order.

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: A digitized multifrequency tone generator comprising a memory having N readable word locations with each location containing an amplitude representing binary word, and with the total N binary words sequentially and collectively representing a period T.sub.o of the waveform of a multifrequency tone such as a chime with certain harmonics contained therein. Memory scanning signals of frequencies Nf.sub.o, where f.sub.o =f.sub.1, f.sub.2 . . . f.sub.n, are each employed, one at a time in a predetermined chime sequence, to repeatedly and sequentially read the N words from the memory to form a sequence of chimes each of whose fundamental tone frequencies is equal to the employed scanning frequency f.sub.o =f.sub.o1, f.sub.o2 . . . f.sub.n, with the said harmonics being reproduced at the proper frequency relative to each scanning frequency. A digital-to-analog device converts the read out binary words to form the aforementioned waveform.

Abstract: An automatic rhythm generator for use in an electronic organ is made more efficient, from the standpoint of rhythm pattern storage, by use of a zero suppression technique. Null instructions, the sole function of which is to allow a clock interval to pass without sounding an audible beat, are eliminated entirely from storage, and thus do not consume any memory capacity. In order to skip the necessary silent clock intervals before the next audible beat, each beat instruction which is stored at a memory address may include an encoded skip instruction commanding a number of clock intervals to be skipped before passing on to the next beat instruction at the next memory address. Alternatively, the skip instruction, in a stored program instrument, may come from software. In either case, the skip instruction controls a programmable frequency divider, which causes clock interval skipping by dividing down the clock frequency to a lower rate before it reaches the memory address counter.

Abstract: An electronic musical instrument which has any desired compass of musical sounds and which produces justly intoned pitches based on any desired pitch or note and which is capable of changing at will during performance the basic pitch or the "do" (of do, re, me, etc.). The instrument has a single master oscillator having means for changing the pulse interval at will and during performance. The output of the oscillator is fed to a system of counters and gates, the output of which is a number of pulse trains which are related in frequency by ratios of small integers and which ratios are maintained unchanged regardless of the frequencies of the various outputs. The instrument includes a keycylinderin place of the usual keyboard and it has on its surface several helices of conductive contacts.

Abstract: A keyboard type electronic musical instrument wherein tone assignment signals (key depression signals) designated by depressing desired keys of keyboards are transmitted to an electronic circuit block through only one signal line per sort of keyboard as time-divided serial timing signals. The electronic circuit block includes therein a circuit which generates parallel output signals having respectively different timings in correspondence with notes of the keyboards. The parallel timing signals are respectively sent to the corresponding key switches of the keyboards, they are selected by turning "on" the switches, and they are converted by OR circuits into serial timing signals representative of the selected notes. The serial timing signals are sent to a device for detecting and storing notes or chords, whereupon as in prior arts, a tone signal is generated from the obtained signal indicative of a note or chord by tone signal producing device and it is amplified and provided as an output by a loudspeaker.

Abstract: A musical instrument tone generator comprises a clock circuit including means for developing an interval code representing the number of musical intervals to be swept by a tone signal. An output clock signal is produced in response to the interval code for causing the swept tone signal to exhibit a rate of change varying exponentially with time such that a number of musical intervals are swept in a corresponding number of equal time intervals. Means are provided for suitably updating the output clock signal in response to the modification of an on-going frequency sweep in order to maintain the foregoing correspondence between the number of musical intervals swept and the time duration of the sweep. In another embodiment, the output clock signal is effective for operating the tone generator for developing a tone signal sweeping one or more musical intervals in an equal time interval.

Abstract: An electronic organ having an improved note generator, an improved control logic circuit for assigning note generators to generate output frequency signals corresponding to selected notes in accordance with the availability of the note generators, and an improved combination of a bass note assignment circuit and bass note generator is disclosed.

Abstract: An electronic musical instrument is of a time-shared digital processing type and capable of producing musical tones for a special performance. There are provided, at suitable time intervals, time periods in which no key code of a depressed key is produced by a key coder. During these time periods, a signal designating a special performance is generated. In a channel assignment circuit which assigns key codes of depressed keys to plural tone production channels there is provided a channel for an exclusive use for the special performance. A circuit for assigning data for the special performance transmits the data to the channel assignment circuit in response to the special performance designation signal from the key coder so that the data selected from among the key data already assigned to the tone production channels for ordinary performance are sequentially assigned to the channel allotted exclusively for the special performance.

Abstract: An electronic musical instrument comprises a keyboard circuit providing a pitch determining voltage signal whose magnitude corresponds to the note of a key depressed, a rectangular wave generation circuit generating a rectangular wave voltage signal, and a voltage controlled oscillator connected to receive the pitch determining voltage signal and the rectangular wave voltage signal to produce alternately first and second tone signals for trill performance. The tone pitch of the first tone signal depends on the magnitude of pitch determining voltage signal and the tone pitch of the second tone signal depends on the magnitudes of pitch determining voltage signal and rectangular wave voltage signal. The musical intervals between tone pitches of the first and second tone signals depends on the magnitude of rectangular wave voltage signal.

Abstract: An automatic accompaniment apparatus capable of automatically producing a bass tone by developing notes constituting a chord in the form of a broken chord in a predetermined order when keys constituting such chord are depressed. When a plurality of keys are depressed, there often exist a plurality of different chords constituted of notes corresponding to the depressed keys. The automatic accompaniment apparatus according to the invention is adapted to detect a single chord name among these plural chords in a certain predetermined order of preference and use the fundamental note and other notes constituting the detected chord as the bass accompaniment tone. The apparatus is capable of selectively restricting generation of notes other than the fundamental note which would normally be generated in the bass accompaniment using a predetermined note as the fundamental note, thereby providing bass variation effects to the generated bass tone.

Abstract: Methods and apparatus are disclosed which are utilized in providing a musical instrument useful for composing, teaching, learning and performing music. The instrument includes a pitch detector which responds to an applied input signal to produce and octave code representing the octave in which the input signal is located and a note code representing the note which is closest in pitch to the input signal. The octave and note codes are applied to display means which indicate the octave and note nearest in pitch to the input signal. The octave and note codes are also applied to an automatic pitch generator wherein they control the dividing down of a high frequency clock signal to produce a true pitch signal having the pitch corresponding to the octave and note codes. The automatic pitch generator also has provision for selectively combining octave and note transpose codes with the octave and note codes to achieve any desired degree of transposition of the true pitch signal.

Abstract: Key switches are connected in a matrix fashion between row lines making block lines for octaves and column lines making note lines for notes. The note lines are connected to a note detection circuit which converts the note line outputs of the actuated switches into key codes in a time shared fashion and to a chord detection circuit which includes a chord type detecting logic and a shift register connected thereto and storing the note line outputs in its respective stages. During a chord detecting period, the note detection circuit is loaded with signals "1" as if all the key switches were actuated and delivers key codes of all notes one after another, whereas the shift register is circulatingly shifted synchronously with the note code change. When the logic detects an establishment of a chord, the note code of that moment is extracted to be a code identifying the root note of the chord. The root note code is then processed for automatic bass and chord performance.

Abstract: An electronic musical instrument is of a waveshape memory read out type which includes a waveshape memory device for storing amplitude values at respective sampling points in one period of a new musical tone waveshape to be generated subsequent to a present musical tone waveshape stored in another waveshape memory device, first calculating means for calculating differences in amplitude values at respective sampling points stored in corresponding addresses of the two waveshape memory devices respectively; renewal rate control means for generating a waveshape renewal signal having a period corresponding to difference information produced by the first calculating means, and renewal means for effecting renewal of the memory content of said another waveshape memory device at a rate corresponding to the period of the waveshape renewal signal.

Abstract: An electronic musical keyboard instrument has a unit separate from the main console and having switching means for performing the function of at least some of the keys and stops of the console that unit being adapted to be operated by a handicapped person.

Abstract: A music synthesizer is disclosed which includes a keyboard for entering musical notes to be synthesized into the music synthesizer. The music synthesizer also includes a rhythm control arrangement, such as push buttons, for selecting prestored repetitive rhythm pattern tempos to be synthesized into the music synthesizer. A single microprocessor computer is provided which processes and establishes priority of signals from the keyboard and the rhythm control buttons for generating signals indicative of the frequency and amplitude of the musical note to be synthesized and for generating musical instrument signals and combining them into the rhythm pattern to be synthesized. A tone generator is provided which is controlled by the computer for generating a squarewave signal having the frequency of the musical note to be synthesized.

Abstract: A circuit for an electronic organ for producing rhythmic patterns of notes in accordance with the selection of a chord in the accompaniment manual. The organ includes an accompaniment manual and a solo manual, either or both of which may be electronically scanned to develop a multiplexed data stream, and a chord generation circuit controlled by the accompaniment manual for sounding groups of notes in the accompaniment voices in response to the depression of one of the selected group of keys on the accompaniment manual. The circuit according to the present invention automatically sounds notes of the solo manual in a rhythmic pattern in response to the depression of one of the group of accompaniment manual keys by developing a logic pulse at the beginning of the top octave scan which is delayed in time to correspond to the time slot of the chord root note and subsequent notes of the chord. The amount of delay is controlled by pre-programmed patterns preselected by the musician.

Abstract: An automatic musical performance instrument which has a counter for counting a high-speed clock from a high-speed clock generator, a depressed key switch detector for generating a scanning pulse in synchronism with the high-speed clock to detect a depressed key switch, a circuit for storing in the form of a binary coded signal the output from the counter corresponding to the depressed key switch, a tone signal converter for converting the stored binary coded signal to a tone signal, and control means for sounding the tone signal in accordance with a rhythm pulse.

Abstract: An electronic metronome has a visual indicator, a loudspeaker, and a duty time setting circuit for setting the visual time of a visual indicator corresponding to each speed of various tempos. Accordingly, it is easy for a singer, a player, etc. to precisely see the predetermined tempo by using the duty time setting circuit.

Abstract: In an electronic organ or the like constructed of a plurality of large scale integrated circuit (LSI) chips, the present disclosure relates to a master control LSI chip having a counter providing multiplexing drive outputs and also having a read only memory (ROM) programmed to provide rhythm voice patterns.

Abstract: An electronic musical instrument having a channel processor. The channel processor includes a tone production assignment circuit and an automatic arpeggio circuit. The tone production assignment circuit includes a key code memory circuit of a plurality of channels and an assignment control unit. A specific channel among the channels is used exclusively for the automatic arpeggio performance while the other channels are used for ordinary respective tone production corresponding to depressed keys by an ordinary key assignment operation responsive to depression of the keys. The automatic arpeggio circuit produces key codes one after another for the automatic arpeggio channel in accordance with the key codes already assigned to the respective ordinary channels and with arpeggio constituent orders in a sounding pattern. The arpeggio sounding pattern which is selected in response to a rhythm to be played contains binary data representing the arpeggio constituent orders.

Abstract: A reference rhythm storing read only memory having a plurality of addresses for storing in advance, in an address sequence, information concerning a reference rhythm pattern and a writable/readable rhythm storing random access memory having addresses corresponding to the addresses of the reference rhythm storing memory for allowing for writing/reading information concerning a desired rhythm pattern unit are provided.

Abstract: A read only memory is provided, which has a plurality of storing regions allotted for a plurality of kinds of rhythm patterns, each region having a plurality of addresses for storing, in an address sequence, a rhythm pattern of a shortest rhythm pattern unit represented by a combination of information units in the form of logic "ones" and logic "zeros", the logic "one"; representing a note being generated and the logic zero representing a note being not generated, whereby the notes are represented in binary form, whereby the required number of information units is reduced compared to the prior art. Each address in the memory has a plurality of bit positions allotted to a plurality of kinds of musical instruments, whereby a plurality of kinds of rhythm patterns are stored for a plurality of kinds of musical instruments.

Abstract: A keyboard type automatic accompanying system wherein information representative of the root note of a chord and the type thereof are detected from key depression signals assigned by depressing a plurality of desired keys of an accompanying keyboard, the detected information are stored, and an automatic chord complying with the particular chord are accompanied. A chord detector comprises in combination a shift register which stores the accompanying key assignment signals therein and which shifts the stored contents cyclically, and a ROM device in which binary information indicative of the basic forms of chord names and the types of chords are stored. Outputs of the shift register are applied to the ROM device, and the type and the root note of the chord are detected in one shift cycle of the shift register, so that the circuit arrangement is simplified, that the detecting time is shortened and that the key response rate is enhanced.