Abstract: A method of synthesizing a musical sound in which a fundamental waveform signal is produced which has a zero crossing point within one cycle period thereof and the phase of the zero crossing point is modulated by a modulation signal to provide a musical tone with a complex waveshape.

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: In a music tone generating system, of entry data keyed in by a plurality of entry keys related to the music tones, the entry data falling within the maximum digits which can be displayed by a display device are displayed by setting up one mode selected. When an entry key is operated to enter entry data exceeding the maximum digits while the former entry data remains displayed, the music tone corresponding to the key depressed may also be generated.

Abstract: An electronic musical instrument comprises a key on-off memory for storing the on-off state of the respective keys, and at a time counter for counting the lapse of time after release of the respective keys. The time counter inhibits generation of the musical tone signal corresponding to the key when the conditions that predetermined time is elapsed after the key release and that the key-off state is stored in the memory are satisfied. This inhibition is separately conducted with respect to the keys. Thus, it can remarkably prevent noise when the tone should not be produced.

Abstract: An electronic organ has a tone generating system for producing tones corresponding to notes of a musical scale. The tones and combinations thereof are selectable to provide different characteristics or "voices" which duplicate the various voices which are selectable on a pipe organ. The character of each such voice is determined by a single generator. The character of the output tone on a per manual basis is alterable by substituting or combining the outputs of different generators. The signal produced in this manner is sampled at a rate which translates it to an audio frequency.

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 a musical instrument having one or more tone generators in which a plurality of data words corresponding to amplitudes of a corresponding number of evenly spaced points defining the waveform of an audio signal composed of a number of unified tones are generated by the combination of three master data sets. The three master data sets are computed separately from stored sets of even and odd harmonic coefficient values. The master data set values are combined using their symmetric properties and are transferred sequentially to a digital-to-analog converter in repetitive cycles at a rate proportional to the unison pitch of the corresponding keyboard note to produce the tone color of a combination of unified tones.

Abstract: A solid state music player for reproducing and playing stored digital information from a magnetic bubble-memory device, which has a magnetic bubble-memory module for receiving the bubble-memory device which contains the stored program. There is also a function-timing generator, which is coupled to the magnetic bubble-memory module for generating control and timing signals for the module. A microprocessor is connected to a bubble-memory controller which in turn is coupled to the function-timing generator, and the bubble-memory controller responds to commands from the microprocessor to send control signals to the function-timing generator, necessary to access the digital data stored in the bubble-memory device. A digital-to-analog converter is coupled to the microprocessor for converting the digital stream of information from the microprocessor into analog signals, which then can be played through loudspeakers or on a video screen to reproduce the stored digital information from the bubble-memory device.

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 having combined monophonic and polyphonic sound producing capabilities includes a keyboard simultaneously operating a monophonic tone signal generating circuit and a polyphonic tone signal generating circuit. The tone signals produced by the tone generating circuits are combined and coupled through a single signal processing stage and therefrom to an output speaker. A gate signal for enabling the monophonic tone signal generating circuit and for operating the signal processing stage is derived at the output of a detector circuit which is responsive to the presence of an audio output from the polyphonic tone signal generating circuit.

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: A plurality of a signal peak detection circuits connected in cascade for operation on a complex waveform input signal, for generating a reference signal having peaks occurring in time with the peaks of the fundamental frequency component of the input signal. The reference signal is processed for producing a voltage proportional to the period between successive signal peaks, which voltage is successively stored and monitored at select times for comparison of the relative magnitude changes in the voltage, for updating an output control voltage.

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: The invention concerns a polyphonic musical synthesizer using digital techniques. The generation of successive wave form patterns makes use of phase data for addressing a wave form memory, and of amplitude and harmonic or octave row data contained in a set of memory blocks. Control of the synthesizer is effected by externally addressing the memory set in order to write the aforementioned data in it.The development of synthesis operations within the synthesizer is conditioned by a sequential chain of reading of the different memory blocks in terms of signals from a plurality of generators.

Abstract: A musical chord system includes a pedal console comprising a plurality of foot-actuated pedal switches, a chord selection switch console comprising a plurality of chord selection switches associated with said pedal switches, and diode matrix logic means interconnecting the chord selection switches with the tone generating circuitry of a conventional electronic musical instrument such as an electric organ whereby chords are sounded upon depression of the foot pedals. By adjustment of the corresponding chord selection switch, each foot pedal can be set to produce any desired one of a multiplicity of possible chords. Switches are also provided to permit the chords to be sounded on different octaves and keyboards or combinations thereof. A priority interconnect circuit prevents more than one chord from being played when two pedals are simultaneously depressed. A lower musical keyboard sustaining circuit permits the upper manual keyboard to be pulsed with alternating partial and full depression of a pedal.

Abstract: A one key chording system for an electronic organ of the type in which single contact keyswitches for D.C. keying of tone signals are employed. The keyswitches of a first group are connected to a common bus to which is also connected a mode select circuit for selectively applying thereto a D.C. potential of either positive or negative polarity. In the disclosed embodiment, when a negative potential is applied to the common bus a signal from an actuated keyswitch in said first group operates one of a plurality of chord logic circuits to produce a plurality of auxiliary keying signals which operate tone signal keyers for tone signals corresponding to a musical chord. An alpha-numeric display disposed adjacent to the keyboard indicates the name of the chord being played by the one key chording system.

Abstract: In a musical instrument having one or more tone generators in which a plurality of data words are transferred sequentially from note registers in repetitive cycles at rates proportional to the pitches of tones being generated, apparatus is provided for varying the spectral content of tones having both harmonic and nonharmonic overtones. Control signals are used to vary the amplitudes of the overtones. An independent formant control signal causes the tones to have a time variant spectral quality.

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: 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: In a digital tone synthesizer of a type using digital data representing the amplitudes of a predetermined fixed number of sample points along one cycle of the audio waveform of a musical tone and an oscillator controlling the sampling frequency as well as the pitch of the tone, a digital filter for transferring the digital data to a digital-to-analog converter at the sampling rate. The digital filter, in response to applied input coefficient values, operates as a low pass or high pass filter in which the cut-off frequency is a predetermined harmonic of the pitch frequency of the tone. By changing the coefficient values, the cut-off harmonic can be changed for a tone independently of the pitch of the tone. Thus any tone of the musical scale may be filtered to modify the harmonic content independently of the pitch of the tone.

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: A method and apparatus for producing sounds from one or more-time overlapg sequences of one or more electrical pulse signals having a frequency corresponding to the pitch of the sound to be produced from the signals holding the pulse width or pulse pause width in each sequence substantially constant for signals corresponding to a range of pitches of the sound to be produced. The pulse widths or pulse pause widths are then relatively abruptly changed over a short interval in pitch at the upper limit of the range. In this way, the shape of each pulse in a sequence and the phase between pulses in concurrent sequences which determine the timbre of the sound remains the same over the range of sounds to permit the method and apparatus to accurately duplicate the sounds of traditional musical instruments.

Abstract: An I.sup.2 L circuit for superimposing audio-frequency electrical signals in an electronic organ is provided. With each current unit of audio-frequency to be superimposed a double-collector I.sup.2 L transistor is associated, and each key is coordinated to an injector, the current of which is switched by said key. In addition to the collecting bars into which said current units are fed, there is provided a separate collecting bar into which the non-audio-frequency collector currents of double collector transistors are fed, each of which being coordinated to each injector. A bounce effect is avoided by subtracting the signal of the separate collecting bar from the signals on the other collecting bars.

Abstract: There are provided means for generating a digital information which varies periodically and repeatedly at a rate corresponding to the pitch of a tone to be produced, a plurality of function generators respectively supplied with the digital information for producing different linear functions, means for selecting the outputs of the function generators at a timing related to the period of the digital information and means responsive to the selected output of a function generator for generating a musical tone.

Abstract: In an electronic keyboard musical instrument, the operation of a key causes a corresponding frequency information signal to be read out of a frequency information memory. The frequency information signal represents a counting number and is repeatedly accumulated in an accumulator at a first clock rate. The accumulator generates carry signals at a frequency defining a tone frequency. A wave shape memory stores sample values of a wave shape, and a counter addresses this memory to read out the wave shape. The counter is driven at a second clock rate to successively address the sample values one after another, but is reset by the carry signals to restore it to its initial state. Thus the memory generates only those sample values of the wave shape which fall within the carry signal period from the beginning. The tone colors will vary from one tone frequency to another.

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 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 simultaneously creating tones at two different pitches. The reference points are computed using specified wave shape symmetry characteristics such that a single variable frequency oscillator suffices to generate both tone pitches without requiring separate, or time shared, tone generation channels.

Abstract: In a musical instrument in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced points defined a cycle of an audio waveform are transformed at an average rate proportional to the pitch of the tone being generated, a frequency generator is provided using a single master clock source for selectively producing the entire range of musical notes. A non-integer frequency generator is implemented which periodically adds a frequency number, corresponding to an actuated keyswitch, to itself in an adder-accumulator. Overflow pulses from the adder-accumulator address out a set of waveshape values stored in a memory. The noise produced by the unequally spaced overflow pulses is reduced by applying optimal amplitude weighting values to the output waveshape values and then adding the weighted values to provide a single value which is converted to an analog signal and furnished as the musical signal.

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 generator chip. The chip is operative over one octave of notes, and a string of chips is cascaded to provide as many octaves as there are in the instrument.

Abstract: A musical waveshape processing system for an electronic musical instrument in which time-division time slots are set corresponding to a plurality of channels for producing notes selected on keyboards of the electronic musical instrument and the notes are each produced by repeatedly calculating the musical waveshape amplitude value of each channel in each time-division time slot. A musical waveshape calculator is provided which calculates the musical waveshape amplitude value as f(t)=at.sup.2 +bt+c based on waveshape data a, b and c and address information t. A multiplier is provided by which the value of an envelope synchronized with the time-division time slot is multiplied by the waveshape data a, b and c.

Abstract: The notes of an accompaniment manual of an electronic keyboard musical instrument such as an electronic organ are multiplexed. The key switches are sequentially scanned and the serial information produced is fed into a shift register. Digital circuitry reads the position of data in the shift register to determine whether a recognized chord has been played. After recognition of a recognized chord a counter operating in conjunction with the shift register clock input operates in connection with comparators and frequency generators to produce the necessary notes for the chord played.An automatic mode of operation also is provided in which only the key corresponding to the root partial of a chord need be played. By utilizing the mathematic relationships in a chord, the simple note played by depression of one key is extrapolated into a chord.

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: A method for producing a tone waveform having a desired spectral construction by modulating an input address signal of a selected frequency for a waveform memory. For the modulation of the input address signal, the output of the waveform memory is multiplied by a parameter .beta. of a suitable value and the multiplication product is added to the input address signal. If the input address varies in the manner of, for example, a saw-tooth wave, a desired tone waveform can be produced within a range between a saw-tooth wave and a sinusoidal wave by selecting a suitable value of the parameter .beta.. More specifically, a saw-tooth wave is produced as a tone wave form if a sufficiently large value of .beta. is selected. As .beta. is gradually decreased, the amplitude is decreased from a higher order and the amplitude also disappears from a higher order until the tone waveform becomes a sinusoidal wave when .beta. is zero.

Abstract: A circuit for generating an audio chime signal, for use on a passenger aircraft, for example to attract the attention of the passengers prior to a public announcement. High and low frequency oscillators are switched on for respective time periods, the low frequency oscillator being switched on after the high frequency oscillator. Decay circuitry causes a progressive decay in the output of each oscillator and a sine shaper removes harmonics of the high and low frequencies.

Abstract: Techniques for translating the harmony expressed by the keyboard playing of a performer into a chord type and root. Playing key pattern representations are stored in a digital memory at locations having addresses defining the corresponding chord type. A playing key pattern signal identifying the pattern of the keys played by the performer is then generated. The playing key pattern signal is used to locate the corresponding stored playing key pattern representation. When a match occurs, the chord type and root are derived by a processor.

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: In a wave shape generator of the memory reading type, a waveshape memory stores sample values of a wave each value being represented by an integral address. A coefficient memory stores coefficients for nth order interpolation. Unknown intermediate sample values not stored in the wave shape memory represented by non-integral addresses and are approximated by multiplication of stored sample values of the waveshape and corresponding coefficient values on the basis of nth order interpolation. Use of the interpolation method assures smoothness of the wave shape with respect to time and thereby minimizes quantization noise while permitting use of relatively small memories.

Abstract: A device for teaching music comprising, in combination, a set of pegs or keys subdivided into seven groups corresponding to the seven musical notes, a set of cards obtained by a sheet material, each card containing a musical passage consisting of coded holes corresponding to the notes of the passage, and means for reproducing the sounds corresponding to each of the seven notes when the respective pegs selectively associated with each hole are first introduced into said holes, and then sequentially depressed.

Abstract: In a musical instrument in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced points defining a cycle of an audio waveform are transferred sequentially from a waveshape memory in repetitive cycles at a rate proportional to the pitch of the tone being generated, apparatus is provided for reducing undesired frequency components resulting from the conversion of the digital signals into analog musical signals. The noise reduction apparatus applies optimal amplitude weighting values to a subset of the stored data words and adds these weighted values together to provide a new single value which is used for the output signal.

Abstract: Apparatus for producing signals of varying volume and pitch which are functions of the magnitude and distribution respectively, of weight (or weights) placed upon a platform hinged at one corner and swingable in mutually orthogonal directions. Sensors convert the physical displacements occurring at first and second corners opposite of the platform adjacent to the hinged corner into signals for controlling the volume and pitch of an output signal. Alternatively, displacement of the platform may be controlled by the application of varying pressure by means other than full body weight, such as the operator's finger(s).The apparatus may be utilized as a unique means for producing music or musical sounds responsive to a person dancing or otherwise moving upon the platform to provide an entertainment form which is both unusual and enjoyable.

Abstract: A wave-shape generator advantageously used for generation of various wave-shape signals on electronic musical instruments comprises, as a substitute for multiple wave-shape memories needed in the conventional wave-shape generators, a combination of a single wave-shape memory with a weighting parameter signal generator. Modulation of the wave-shape signals via multiplication by corresponding weighting parameter signals enables formation of a wide variety of different wave-shape signals without enlargement in construction, the wave-shape signals being changeable even in a time-functional fashion too.

Abstract: This is an electronic organ drawbar circuit in which selection of the footage volumes is accomplished by means of a switch matrix; and sets of footage/volume correlations so chosen are stored in a memory. Another group of switches is used to select among several different memory fields, so that various sets of footage/volume data can be stored while another set of data is in use, and each stored set can be recalled for subsequent re-use.

Abstract: An electronic musical instrument is capable of processing, by the same processing circuit, parameter control analog information signals defining the shape of control waveforms for the modulation of musical tone signals, and analog musical tone signal generation mode select signals for selecting, for example, a musical tone signal waveform and filter characteristic. The parameter control analog information signals and generation mode analog select signals are both optionally set by a player and are multiplexed in a time sharing manner by an analog multiplexer. The multiplexed analog signals are converted into digital signals, which are converted into analog signals, and further demultiplexed. In a write mode, the digital signals are stored in a memory, while, in a read mode, the digital signals are read out of the memory, converted into analog signals, and demultiplexed.

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: For generating tones in an electronic musical instrument, there are provided multiple master frequency sources, a different source for each octave, differing in frequency from each other by a factor which differs from two by at least one semitone, each of which is coupled to a respective frequency synthesizer all of which have the same dividing ratios, to divide down the frequency of its master frequency source to pitches of the twelve notes in the intended octave. In one embodiment the sources are separate master clock pulse sources, and in another embodiment a pulse train derived from a single clock pulse source is applied to the frequency synthesizer for the highest octave, and the pulse train applied to each of the other synthesizers is derived from the pulse train supplied to the frequency synthesizer for the next highest octave by dividing the pulse repetition frequency thereof by a factor which differs from two by one or more semitones.

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 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: 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: In an electronic musical instrument, the keys of a keyboard are divided into a plurality of groups by octaves, and a wave generator is provided with a memory for storing constants corresponding to musical tone frequencies to be generated according to the notes includes in a desired group out of the plurality of group, an accumulator for repeatedly adding the constants read out of the memory, and a bit position shifting circuit for shifting the bit position of the data produced by the accumulator according to the octave range of a note to be produced, thereby to obtain the data varying repeatedly according to the frequency of a note to be produced, and to reduce the storing capacity of the memory when compared to the number of keys.