Abstract: The system comprises a master module and slave modules able to be chain-connected and/or star-connected by means of a digital communication network, for example of the Ethernet type. The system is synchronized on the master module clock that supplies synchronization information to all the data frames it sends over the network. Each slave module reconstitutes the clock from the frames it receives. The data frames comprise data packets that can in particular be command data, audio data or video data. Each packet comprises a header describing the content of the packet. Each slave module knows at which location of a packet the data intended for it is located and at which location of a packet it can insert data.

Abstract: In a typical musical tone producing device of a full waveshape readout type, a full waveshape of a musical tone to be produced from the start to the end of sounding or a rise portion and a part of the waveshape following the rise portion of the musical tone is stored in a waveshape memory, and the musical tone is formed by reading out the waveshape from the waveform memory once, or reading out the rise portion once and thereafter reading out the partial waveshape repeatedly. A digital filter is introduced following the waveshape memory in this tone producing device. The filter characteristics are determined in accordance with a tone color change parameter such as the key touch or the tone pitch of the musical tone, thereby realizing a tone color change of the musical tone. Further, in order to realize timewise change of tone color of the musical tone, the circuit which has the tone color change parameter vary with time is proposed.

Abstract: A pitch synchronizing signal snychronized with the pitch of a digital tone signal to be filtered is generated by a pitch synchronizing signal generation circuit. A digital filter circuit which receives the digital tone signal and imparts it with a desired tone color by subjecting it to a proper filter operation executes this filter operation with a sampling period synchronized with the pitch synchronizing signal. A moving formant thereby is realized which is suitable for control of a tone. A pitch synchronization output circuit for sampling and outputting the output of the digital filter circuit in accordance with the pitch synchronizing signal may be provided and this will prevent occurrence of a sampling noise. A switching circuit is provided for enabling switching order of the digital filter circuit between an even number and an odd number. By this switching of order, a desired filter characteristic can be realized with high fidelity.

Abstract: In storing digital tone waveshape data in a waveshape memory, sampled tone waveshape data is stored in the memory by previously elevating the level of frequency components in a predetermined high frequency region. This predetermined high frequency region corresponds to a frequency region to which quantization noise components belong. The tone waveshape data stored in the waveshape memory in this manner has the signal level of the component of the region including the quantization noise components reinforced as compared with the original tone waveshape. The tone waveshape data read out from the waveshape memory is applied to a filter of a characteristic which restrains the level of the component in the predetermined high frequency region. The level of the quantization noise components belonging to the predetermined high frequency region contained in the tone waveshape data thereby is restrained.

Abstract: A tone control apparatus for use in an electronic musical instrument is responsive to an easily accessible switch such as a foot-lever switch to control conditions of muscial tone which include, for example, a tone pitch, a tone color, a tone volume and a tone effect. The tone control apparatus has a keyboard for designating a frequency of a musical tone to be generated and a musical tone generating circuit for generating a musical tone having a frequency designated by the keyboard. The tone control apparatus further has a memory for storing a plurality of groups of tone control data. Each time the foot-lever switch is operated by the performer, one of the tone control data group is read and supplied to the musical tone generating circuit to control the conditions of the generating musical tone. In a first mode, the plurality of tone control data groups are sequentially read in synchronization with the operations of the foot-lever switch.

Abstract: A peripheral control circuit for a computer system. Independent control and interface circuits are provided for left and right audio channels, for a communications port, for storage media, and for joysticks or paddles. Control logic is provided for direct memory access to system memory and for interrupts to the processor by each of the peripherals. Sound data corresponding to a sound waveform during a particular time period is fetched using DMA or interrupts. Registers store data for selecting the output rate of the sound data, the length of the sound waveform, and the volume of the sound waveform. Four audio channels and two separate audio ports are provide.

Abstract: A time-changing coefficient digital filter having a data RAM for storing input data, a purality of N data registers at the output of the data RAM forming a delay element, a coefficient RAM storing coefficient values, coefficient registers temporarily storing respective coefficients, and a multiplier for multiplying data read out of data registers and coefficient registers respectively. Data from the multiplier and inputs is accumulated in an adder. Coefficient registers and data registers are updated by data from the data RAM and coefficient RAM. The coefficient digital filter provides a sum of products sequentially read out of the coefficient and data registers. The digital filter is applied to produce a musical instrumet having improved tonal qualities.

Abstract: A tone signal generating apparatus comprises a waveform memory in which a plurality of waveform data representing different waveforms but corresponding to a same tone name are stored. These different waveform data are sequentially read from the memory and are supplied to a digital low-pass filter which comprises a delay circuit and a multiplier connected to each other to form a feedback loop. The low-pass filter smoothes abrupt variation of the waveform data and outputs a smoothed waveform data thereby interpolating the different waveforms. A tone signal is produced in accordance with this smoothed waveform data.

Abstract: In the production of a desired musical waveform by combining harmonic components corresponding to respective harmonic orders, each harmonic component value is controlled by a selected cut-off harmonic order qc, level Ha and slope of the formant filter characteristic. The cut-off harmonic order qc, the level Ha and the slope values can each be varied over a predetermined range. Therefore, the slope values of the formant filter characteristic are interpolated to raise resolution, by which it is possible to prevent an abrupt change in the formant filter characteristic and suppress the generation of noise.

Abstract: An amplifier circuit for use with a guitar. It has two modes, a "clean" output mode, and a "super-distortion" mode, which mode has independent gain control prior to a distortion stage. There is also post distortion gain control.

Abstract: A plurality of waveshapes of different characteristics are stored in a waveshape memory among which a waveshape to be read out is selected in accordance with a selected tone color or elapse of time and data of the selected waveshape is read out. At least one waveshape among the waveshapes stored in the waveshape memory is coded in a coding form different from one used for the other waveshapes. For matching characteristics of each individual waveshape, waveshapes are coded according to respectively suitable coding forms such, for example, that one waveshape is coded according to the pulse code modulation system, another waveshape according to the differential pulse code modulation system and still another waveshape according to the delta modulation system. The waveshape data read out from the waveshape memory is converted in its code to a predetermined common coding form (e.g. PCM).

Abstract: A tone generator includes a plurality of tone generation channels each comprising one or more operation channels. One operation channel performs basic operation of a tone signal computing operation (e.g., FM or AM) and a tone signal is generated by using one or more operation channels for one tone generation channel. Tone generation channels in the tone generator are established according to a selected performance mode. In a first mode, the operation channels are divided into N groups and N tone generation channels are established in correspondence to the respective operation channel groups. In a second mode, the operation channels are divided into M groups and M tone generation channels are established in correspondence to the respective operation channel groups wherein N is a different number from M. Tone generation channels of the number required according to the selected performance mode can be established by efficiently utilizing the operation channels of a limited number.

Abstract: A musical tone signal generating apparatus generates a musical tone signal whose tone color can be changed independently of a pitch or a frequency of the musical tone signal. The musical tone signal generating apparatus comprises a shift register on which sampled data of a predetermined waveform are initially loaded. The sampled data in the shift register are shifted at a frequency corresponding to a rate of change of the tone color, and each sampled data shifted out of the shift register is subjected to a predetermined operation such as a multiplication by a predetermined coefficient and is fed back to the shift register. The sampled data in the stages of the shift register are selectively outputted by a selector controlled in accordance with selection control data formed based on the pitch of the musical tone so that the sampled data are outputted at a rate determined by the tone pitch. The musical tone signal is then formed based on the thus outputted sampled data.

Abstract: In a tone signal generation device, original waveshape amplitude data corresponding to a waveshape signal from an external source is stored in a first memory. Waveshape data is read out from this first memory and is properly modified by a tone processing circuit such as a filter or a modulation effect circuit. The modified waveshape data is reserved in a second memory. The waveshape data stored in the second memory is selectively transferred to the first memory. In this manner, the original waveshape data initially stored in the first memory can be freely modified and a tone can be produced with a high degree of freedom as in a music synthesizer.

Abstract: An electronic source synthesizer that employs frequency modulation. Wave-form data of both a fundamental wave and a modulated wave are stored in a RAM as 6-bit digital data. A sine wave signal is produced by modulation wave frequency data and the wave-form data from the RAM. The sine wave signal is multiplied with amplitude data of the modulation wave to obtain the modulation index data (J(t)). The frequency data (w.sub.c) of the fundamental wave and the modulation index data are multiplied. A result of the multiplication provides a read out address of the RAM for storing the wave-form data of the fundamental wave, thereby changing the read out speed of the RAM. The digital data read out from the RAM is converted to an analog sound signal by a D/A converter. Amplitude data (A) of the fundamental wave is pulse-width modulated, and the digital data from the RAM is gated by the modulated pulse. Thus the output of the D/A converter is activated and, forms a sound signal represented by the equation e=A sin J(t) w.

Abstract: There is provided a selection switch for selecting musical information determining characteristics of a tone such as a tone color. This selection switch is pre-assigned with first musical information. Switches and circuits are provided for assigning second musical information to the selection switch. This second musical information is one selected as desired from among plural musical information. Thus, at least two musical information of the pre-assigned first musical information and the selectively assigned second musical information are assigned to the selection switch. There is also provided a mode selection switch. When a first mode has been selected by this mode selection switch, a characteristic of a tone to be produced is determined by the first musical information. When the second mode has been selected, a characteristic of a tone to be produced is determined by the second musical information.

Abstract: In an electronic musical instrument of the waveshape memory type including at least one waveshape memory for storing and reproducing sample values of a musical sound wave to be generated, the waveshape memory stores the sample values of the complete waveshape of a musical tone with a shaped envelope.

Abstract: A computerized system into which is fed the nominal values of a musical score, the system acting to process these values with respect to the relative loudness of different tones in a succession thereof, changes in the duration of the tones and other deviations from the nominal values which together constitute the microstructure of the music notated by the score. The system yields the specified tones of the score as modified by the microstructure, thereby imparting expressivity to the music that is lacking in the absence of the microstructure.

Abstract: A basic tone signal generator and a difference signal generator are provided. A desired tone signal is obtained by synthesizing a basic tone signal and a difference signal generated from these generators respectively. The basic tone signal has principal characteristics of a desired tone signal whose tone color (waveshape) changes subtly with time as in a tone of an acoustic musical instrument, but it is not the desired tone signal itself, including some errors, i.e., difference from the desired tone signal. The difference signal represents the difference between the desired tone signal and the basic tone signal. Since the basic tone signal is constituted by basic tone data whose data amount can be substantially reduced as compared to an amount of data required for reproducing the desired tone signal itself with a high resolution and the difference signal is constituted by difference data whose data amount can be very small.

Abstract: In this electronic musical instrument a musical tone is generated by repetitively reading out a waveshape stored in a memory. Repetitive sets of phase information are produced, such phase information thus being a linear saw-tooth-like digital signal having a repetition period corresponding to the frequency of the generated musical tone. Phase distorting means modifies the shape of the phase information so as to distort said linear saw-tooth-like signal, without changing the repetition period thereof. The resultant altered phase information is used to access said memory so that during the supply of each of said repetitive sets, successive samples in different portions of said stored waveshape respectively are read out at different effective rates. Thus the waveshape samples read out from said memory will consitiute a musical tone having changed tone color but unchanged pitch.

Abstract: In a typical musical tone producing device of a full waveshape readout type, a full waveshape of a musical tone to be produced from the start to the end of sounding or a rise portion and a part of the waveshape following the rise portion of the musical tone is stored in a waveshape memory, and the musical tone is formed by reading out the waveshape from the waveform memory once, or reading out the rise portion once and thereafter reading out the partial waveshape repeatedly. A digital filter is introduced following the waveshape memory in this tone producing device. The filter characteristics is determined in accordance with a tone color change parameter such as the key touch or the tone pitch of the musical tone, thereby realizing a tone color change of the musical tone. Further, in order to realize timewise change of tone color of the musical tone, the circuit which has the tone color change parameter vary with time is proposed.

Abstract: A keyboard operated musical instrument is disclosed in which musical tones having a variable spectral content are produced from waveshape data values that read out from a stored set of waveshape data points. A second set of data values is computed at the same rate as the rate for sequentially reading out the stored set of data values. A data select means periodically selects a sequence of the read out waveshape data points followed by the selection of a sequence of points from the second set of data values. The selected data points are converted into audible musical tones. Provision is made for varying the shape of the second set of data values in a time dependent fashion as well as to vary the time for which each data set is selected.

Abstract: An electronic musical instrument comprises: a keyboard circuit for generating a pitch data signal which designates the note name of a musical tone to be produced; a speech signal generator for generating a speech signal which tells in human voice the name of the designated musical tone; multiplexed processing circuit for time-divisionally processing the pitch data signal and the speech signal; and sound signal producing circuit for producing the musical tone and the human voice in accordance with the processed output from the multipled processing circuit. Thus the instrument speaks the names of the tones as it produces the musical tones.

Abstract: The present invention provides a tone color control so that the tone color in an attack portion of a tone to be generated differs depending upon whether or not a slur effect is to be imparted. If, for example, the slur effect is not imparted, a tone color for an attack portion of a tone which is rich in variation is used, whereas if the slur effect is to be imparted, a stable tone color which is the same as the sustain portion of a tone is used. In another aspect of the invention, in the case of imparting the slur effect, a tone signal is distributed to two channels and envelopes of signals in the respective channels are separately and independently controlled by separate control signals. In one channel, a control signal of decay characteristics is used whereas in the other channel, a control signal of attack characteristics is used. The changing rate of the control signal of the attack characteristics is made greater than that of the control signal of the decay characteristics.

Abstract: An interactive music performance system employs a synthesizer, a programmable computer, and at least one performance device for permitting a user input. The computer is programmed with algorithms which automatically generate controls and interpret a performer's actions in the context of music and sound generating variables, and apply those controls to a synthesizer to determine its production of music. The system is interactive in that a user can direct the system's production of music, as he or she hears it being produced, by use of the performance device. If the user does not provide an input, the system proceeds automatically under control of the performance algorithm.

Abstract: Waveshapes of plural periods for plural channels having characteristics different from each other are stored in a waveshape memory and read out from it when a musical tone is to be produced. Read out waveshapes are respectively weighted by weighting data supplied from a weighting data generator and thereafter a desired tone waveshape is obtained by electrically or acoustically combining these weighted waveshape. As an example, the waveshapes are composed of plural attack waveshapes equal in number to channels and only one sustain waveshape. In this case, the attack portion of the musical tone is formed by the combined one of the attack waveshapes and the sustain portion is formed by the sustain waveshape. This enables the memory capacity of the waveshape memory to be reduced and facilitates the complex tone color control in the attack portion. In another case, each of the waveshapes is composed of an attack portion and a sustain portion, sustain waveshapes forming the sustain portions being matched in phase.

Abstract: A computerized system into which is fed the nominal values of a musical score, the system acting to process these values with respect to the amplitude contour of individual tones, the relative loudness of different tones in a succession thereof, changes in the duration of the tones and other deviations from the nominal values which together constitute the microstructure of the music notated by the score. The system yields the specified tones of the score as modified by the microstructure, thereby imparting expressivity to the music that is lacking in the absence of the microstructure.

Abstract: A keyboard operated musical instrument is disclosed in which musical tones are created by reading out data values stored in a waveshape memory. The number of stored data points is reduced by storing the data values in segments corresponding to one-half of the number of data points for a period of a waveshape. By using synthesized data having a symmetry about the midpoint, the second half of the waveshape is recovered by a forward and backward memory address read of each waveshape segment. After reading each segment a predetermined number of cycles, an abrupt jump is made to the next segment of waveshape data points. The fundamental frequency of the tone is varied in a temporal manner by changing the memory advance rate of reading waveshape data out of memory in response to a frequency offset data corresponding to each segment of the waveshape data. An alternative embodiment is disclosed for a tone generator in which the musical waveshape is computed in real time from stored sets of harmonic coefficients.

Abstract: A preamplifier circuit for enhancing sound generated by a musical instrument such as a guitar and which is converted into electrical signals includes an input, a passive high impedance input network connected to the input, a first preamplifier connected to the passive input network for non-distortion amplification of the electrical signals in a first mode of operation and for saturation distortion amplification of said electrical signals in a second mode of operation. A switch circuit enables switching between the first and second modes of operation. An overdrive amplifier bridges across the passive input network in response to the switch circuit for overdriving the first preamplifier thereby to cause saturation distortion amplification of the electrical signals. A shunt network may be switched across the output terminal to equalize output amplitude of the preamplifier circuit between the first and second modes of operation.

Abstract: A digital filter is provided between a tone signal generation circuit which supplies a digital tone signal in accordance with a first sampling frequency and a sampling circuit which resamples this digital tone signal in accordance with a second sampling frequency which is lower than the first sampling frequency. This digital filter filters the input digital tone signal with such amplitude-frequency characteristics as to be able to substantially remove an aliasing noise produced due to the second sampling frequency (e.g., with low-pass filter characteristics having a cut-off frequency which is 1/2 the second sampling frequency). This removes high frequency components producing an aliasing noise from the digital tone signal before it is applied to the resampling circuit whereby generation of the aliasing noise in resampling is prevented.

Abstract: In the production of a desired musical waveform by combining harmonic components corresponding to respective harmonic orders, the cut-off harmonic order q.sub.c, each harmonic component value is controlled by selecting the level Ha and the slope of the Formant filter characteristic. The cut-off harmonic order q.sub.c, the level Ha and the slope value can each be varied over a predetermined range. These operations can be performed with a simple circuit arrangement involving a small number of memories. Therefore, the present invention greatly contributes to the reduction of the size and the cost of electronic musical instruments.

Abstract: A touch sensitive electronic musical or sound generating instrument is disclosed. The invention utilizes digital techniques to sense how hard any one of a plurality of push buttons on a keyboard is depressed or actuated. The instrument generates a desired or particular sound (such as a musical note) at a desired parameter such as volume, corresponding to how hard a specific button was depressed.

Abstract: An automatic musical accompaniment playing system for use in an electronic musical instrument with an auto rhythm system changes a tone color of accompaniment tones when the state of operation of the auto rhythm system is changed. The automatic accompaniment playing system comprises a tempo clock generator for generating tempo clock pulses having a frequency proportional to a tempo of a rhythm to be generated and a register for storing a flag indicative of a state of operation of the auto rhythm system. The tempo clock pulses are counted by a tempo counter when the auto rhythm system is in operation, and the state of operation of the auto rhythm system is detected in accordance with the state of the flag. A memory stores two groups of tone color data, one of which is selected when the auto rhythm system is in operation, and the other of which is selected when the auto rhythm system is not in operation.

Abstract: An audio processing system for injecting left and right channel audio signals with a signal having a fundamental frequency component that is half the frequency of the highest amplitude low frequency component in the left and right channel audio signals. The left and right channel audio signals are combined to form a monaural signal that is low pass filtered and applied to a demodulator circuit. The demodulator circuit generates a control signal having a frequency that is half the frequency of the highest amplitude frequency component in the signal at the output of the band pass filter. The control signal varies the phase of the signal at the output of the band pass filter according to the polarity of the control signal. The resulting signal is selectively added to the left and right input signals.

Abstract: A keyboard operated musical instrument is disclosed in which musical tones are created by computing waveshapes from a set of harmonic coefficients. Tones with time variant spectra are obtained by scaling each harmonic coefficient in response to a stored set of scaling numbers. An efficient scaling implementation is described which changes the harmonic coefficients by increments of a predetermined ratio. The tone generation system provides a significant reduction in the number of stored numbers in comparison with a simple stored waveform tone generator.

Abstract: A system for converting musical sounds into digital data for use with a electronic synthesizer. An infra red pitch sensor detects pitch of string vibration. Envelope of this signal is filtered and applied to a comparator with floating threshold. Square wave output of comparator is used to reset a continually running counter and latch valid data into a latch. Valid data is used as address for a memory which contains quantized values corresponding to standard musical notes. Transposition of keys may be accomplished in memory lookup table. Amplitude of input signal is detected by A/D converter, and with pitch information from memory lookup table is sent to processor. Processor makes decision when valid data is present, and when present outputs data to synthesizer.

Abstract: A sound interface circuit is implemented in large scale integrated circuitry (LSI) on a single chip to provide 3 voice electronic music synthesizer/sound effects, and is compatible with instructions from commercially available microprocessors; whereof a wide range, high-resolution control of pitch (frequency) tone color (harmonic content) and dynamics (volume) is achieved and specialized control circuitry minimizes software overhead, facilitating use in arcade/home video games and low cost musical instruments.

Abstract: A keyboard is capable of being used by splitting it in plural key areas at a predetermined split position or positions. A tone forming circuit generates a tone signal corresponding to a depressed key in each key area in a tone generation manner corresponding to one of the split key areas. A plurality of key touch sensors are provided in correspondence to splittable key areas. In case that a certain key split mode is being selected, each touch sensor outputs a touch signal representing a degree of depression of the depressed key in a corresponding key area and supplies it to the tone forming circuit. The tone forming circuit imparts the tone signal for each key area with a touch responsive characteristic in accordance with the corresponding touch signal, thereby performing a properer touch response control in an electronic musical instrument.

Abstract: Data for each sample point amplitude values of a desired waveshape is expressed in mantissa and exponent in accordance with a floating-point representation. The desired waveshape is divided into a plurality of frames along a time axis and the exponent data is common in each individual one of said frames which includes a plurality of sample points. The number of the frames is much smaller than the number of all sample points. In this waveshape memory, the mantissa data corresponding to the respective sample points are stored in a first memory, and exponent data corresponding to the respective frames are stored in a second memory.

Abstract: An electronic musical instrument includes circuitry for modifying an ordinary address signal which changes at a uniform rate over one cycle of a waveform, into a modified address signal whose rate varies in one cycle of the waveform by the use of a modification signal.The modified address signal accesses a storage device such as a ROM in which waveform data is stored, thereby producing the modified waveform data from the storage device. The modification signal is obtained from the ordinary address signal through a predetermined logic circuit.

Abstract: In a musical tone synthesizer in which an amplitude-modulated carrier wave delivered from an amplitude modulator is used to form a musical tone signal, the amplitude-modulated carrier wave is fed back to the input side of the amplitude modulator as a modulation signal, a portion thereof, a portion of a carrier wave or a composite signal of the modulation signal and the carrier wave. The amount of feedback may be controlled by multiplying the amplitude-modulated carrier wave with a predetermined modulation index. Furthermore, the modulation index may be charged with time so that the control of spectrum construction of the musical tone signal is readily performed. According to a modified embodiment, a plurality of amplitude-modulators are provided which are connected in a ring form feedback loop in which the modulated outputs of preceding amplitude modulators are supplied respectively to succeeding amplitude modulators.

Abstract: A plurality of envelope generating circuits provide output envelope waveforms which are controlled according to the output from a plurality of timbre switches. The envelope waveform of at least one of the envelope generating circuits is modified according to a touch data output of a touch data detecting circuit for detecting a way of operation of a performance key.

Abstract: A musical instrument employing probabilistic wavetable-modification method of producing musical sound. A randomly initialized wavetable which is periodically accessed to provide an output signal which determines the musical sound. The output signal from the wavetable is probabilistically modified and stored back into the wavetable as modified data. The modified data, after a delay, is accessed from the wavetable and thereby becomes a new output signal. This process is periodically repeated whereby each new output signal is stored (after possibly being modified) back into the wavetable to produce rich and natural musical sound.

Abstract: An electronic musical instrument comprises a plurality of keyboards each having a plurality of keys, a control circuit for controlling a manner of tone production, and a musical tone production circuit responsive to respective depressed keys of respective keyboards. The control circuit controls the musical tone production circuit in response to operation of a switch mounted on a control panel for manually selecting one of a plurality of sets of preset parameters corresponding to a kind of a musical tone to be performed. The musical tone production circuit modifies a tone specified by a depressed key in any keyboard according to the selected switch on the control panel.

Abstract: For amplified musical instruments such as electric guitars, this method of extending the range of timbre variation available from a "wah" type of pedal controlled sound modification effect provides musicians with increased flexibility of expression by including within the controlling range of the foot pedal an unmodified "dry" condition in addition to the variable modified condition with the capability of blending smoothly back and forth between the two conditions.

Abstract: An electronic musical instrument is provided with a temporal variation circuit of SCF parameters for temporally varying the filter characteristic of a switched capacitor filter circuit, a control circuit for digitally controlling the temporal variation circuit and a touch response circuit for detecting, by scanning, touch response data in performance, whereby temporal variations of a musical waveform signal are digitally controlled.

Abstract: A musical tone producing device of a waveform readout type has a reference waveform memory and a difference waveform memory.The reference waveform memory stores a reference waveform which is similar commonly to each of divided waveforms belonging to a plurality of blocks into which a musical tone waveform of a musical tone to be produced is divided.The difference waveform memory stores difference waveforms, each of which is a difference between the reference waveform and each of divided waveforms.The reproduction of the musical tone waveform is accomplished by reading out the reference waveform and the difference waveforms successively and by successively adding the read out reference waveform and the difference waveforms. This musical tone waveform synthesis according to utilization of difference waveforms contributes to the reduction of memory size.

Abstract: An electronic musical instrument is provided with a first programmable counter for generating a reference clock signal corresponding to a musical frequency and a plurality of cascade-connected programmable counters which are each triggered by the preceding programmable counter. A multi-level signal which assumes one of a plurality of levels for each period specified by one of the cascade-connected programmable counters is output as a primary waveform. The electronic musical instrument is capable of setting various variations of the primary waveform abundantly containing harmonics and is satisfactory in the tone quality and in the degree of freedom in setting tones, and hence is of high musicality.

Abstract: In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, temporal variations of the musical waveform and its timbre variations in accordance with a touch response are controlled with respect to readout addresses for reading out a set of harmonic coefficient data for the Fourier synthesis from a memory having stored therein a plurality of sets of such harmonic coefficient data, thereby changing the component ratio of a harmonic coefficient which will ultimately be used as a Fourier coefficient.

Abstract: A keyboard operated electronic musical instrument is disclosed which has a number of tone generators that are assigned to actuated keyswitches. The generated musical tones are selectively varied in tone color by multiplying tone data values by a masking function. A library of masking functions are stored and are selected by a control signal. Musical tones with time variant harmonics can be generated.