Abstract: Calculations by an envelope circuit and a waveform calculation circuit, which are principal functions of an electronic musical instrument, can be performed by the same calculation routine through use of the same general formula A=B.+-.C.times.D. Accordingly, their circuit structures are substantially simplified and the circuits can be fabricated as a one-chip large scale integrated circuit.

Abstract: An electronic musical instrument comprising a host processor (10), process/engine interface (12) and sound engine (14) the latter utilizing partial control chip modules (32, 34) and a data path chip module (36) to effect multiple partial (Fourier) synthesis, in conjunction with a sound modelling technique, to generate up to 240 independent partials and impress time-varying amplitude envelopes on them and select and apply them to sound generation, each partial being controlled by selected parameters of frequency, amplitude, phase and attack/decay rate. A modulo-sumdither and oversampling approach to noise reduction is utilized in connection with the data path chip arrangement. Log sine addition is utilized to avoid multiplication apparatus ordinarily required to combine sine wave defining parameters.

Abstract: Apparatus is disclosed whereby an electronic musical tone generator is controlled in response to a musical instrument using mechanically vibrated strings. A bank of digital note filters is associated with each string to find the closest true musical note frequency corresponding to the vibration frequency of the string. The filters operate by computing the autocorrelation function of the string's vibration waveshape and then performing a Fourier transform to obtain the identification of the closest true musical note. An efficient and simple implementation is disclosed for an analog-to-digital signal conversion, the computation of the autocorrelation, and the Fourier transform. Provision is made for introducing frequency changes corresponding to a pitch bend in the vibration frequencies of the string.

Abstract: A musical tone signal is synthesized on the basis of a predetermined modulation operation (e.g. an FM or AM operation) employing a modulating signal and a carrier signal respectively having an audio range frequency. The modulating wave signal and/or carrier signal is derived by reading out a predetermined waveshape signal from a waveshape table in accordance with progressive phase angle data. The value of the waveshape signal read out from the waveshape table is modified in a specified phase section. This modification is effected by applying a simple operation such as gating, shifting or selecting to the phase angle data addressing the waveshape table or to the waveshape signal read out from the waveshape table. The modified waveshape signal is utilized in a predetermined modulation operation as the modulating wave signal and/or carrier signal.

Abstract: The present invention is directed to an electronic musical instrument which has a circuit for calculating a harmonic function corresponding to a fundamental wave. The electronic musical instrument is provided with a circuit for generating, as the harmonic function, an in-tune function corresponding to an in-tune harmonic, a circuit for generating a phase function which imparts an arbitrary frequency number log to the in-tune harmonic and a circuit for multiplying the in-tune function and the phase function, whereby a tone close to a natural tone of an acoustic musical instrument can be created at a relatively low cost.

Abstract: An electronic bell-tone generating system selectively provides a plurality of bell tones having improved tonal quality includes a plurality of tone generators operated in preselected combinations by a microprocessor in response to inputs from a keyboard. Data representing characteristic bells, including a fundamental tone and associated partial tones, their initial amplitude, and decay rate, is stored within a random access memory, input periodically to the respective tone generators comprising double-buffered, digital-to-analog converters, and output simultaneously to produce the "strike" of a bell.

Abstract: A musical tone generating apparatus for an electronic musical instrument utilizing a data compression system is disclosed. This musical tone generating apparatus is basically constructed by a memory storing difference data and a data reproduction circuit. The difference data is in advance obtained by converting a musical tone signal to be reproduced to digital sample data, effecting a linear prediction operation on the digital sample data to produce prediction data and calculating the difference between the digital sample data and the prediction data. The stored difference data are sequentially read from the memory. In the data reproduction circuit, the musical tone signal is reproduced by effecting a reverse operation of the linear prediction operation on the read difference data.

Abstract: An electronic musical instrument includes a waveshape generator which generates first and second waveshapes having a pitch corresponding to a designated note. The first waveshape represents a complete waveshape produced by a certain musical instrument under a certain extreme condition (e.g., the hardest key touch). The second waveshape represents a complete waveshape produced by the same musical instrument under another extreme condition (e.g., the softest key touch). The electronic musical instrument further includes an interpolator which interpolates the first and second waveshapes in accordance with a playing condition (e.g., the strength of key touch) and produces and interpolated new waveshape as a waveshape of a musical tone to be produced. The introduction of this interpolator enables any waveshape under an intermediate condition to produce by preparing only two waveshapes under the two extreme conditions.

Abstract: A musical tone signal is synthesized on the basis of a predetermined modulation operation (e.g. an FM or AM operation) employing a modulation signal and a carrier signal respectively having an audio range frequency. In a waveshape table provided for defining at least one of a modulation wave function or a carrier wave function, a wave function expressed in a logarithmic form log{f(x)} is stored. The wave function log{f(x)} read out from this waveshape table is multiplied with a coefficient k whereby the wave function of the modulation signal or the carrier signal to be used in the modulation operation is changed from f(x) to {f(x)}.sup.k. That is, k log{(f(x)}=log{f(x)}.sup.k is obtained by this multiplication and {f(x)}.sup.k is obtained by converting this log {f(x)}.sup.k to a linear form. Therefore, it is enabled to synthesize a tone having abundant frequency components by using the wave function {f(x)}.sup.k obtained by a simple operation.

Abstract: A tone generation control unit has four waveform read/write channels for selectively reading or writing data in a waveform memory. A plurality of waveform signals stored in the waveform memory are converted into analog signals to be subjected to timbre and tone volume control through voltage-controlled filters and voltage-controlled amplifiers before being fed to a mixing adder. An output signal of the mixing adder is converted into a digital signal which is stored in the waveform memory again through processing of the tone generation control unit.

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: Tones of percussion instruments produce different timbres, i.e. different tone waveshapes, depending on the strength of percussion. An automatic rhythm apparatus includes a rhythm tone generating unit which stores the tone waveshape produced from a hard percussion and also that from a soft percussion performed on a same percussion instrument. A rhythm pattern is constructed by rhythmically aligned tone command signals, for various percussion instruments, designating timings and volumes of tones to be produced. At each tone production, these two kinds of waveshapes are read out by mixing them appropriately. That is, when a loud tone is to be reproduced, its waveshape is read out from the waveshape memory for loud tones, while a soft tone is read out likewise from the waveshape memory for soft tones, and a tone of an intermediate volume therebetween is reproduced by reading out the loud tone and the soft tone at a mixing ratio complying to the desired degree of volume.

Abstract: A keyboard operated musical instrument is disclosed in which dual musical tones are created by reading out data values stored in a waveshape memory. Waveshape data values are read out alternately by two memory addressing circuits. One memory addressing circuit addresses out waveshape data values at a constant memory address advance rate corresponding to the fundamental frequency of an actuated keyboard switch. The second memory addressing circuit addresses out waveshape data points at a time variant memory advance rate. The two sets of read out waveshape data values are combined to produce a dual musical tone.

Abstract: An electronic musical instrument includes a first waveform memory for storing a waveform corresponding to an attack portion of a musical tone and one period of a steady waveform produced after the attack, a second waveform memory for storing one period of a waveform different from the contents of the first waveform memory, a waveform reader which reads out the first and second waveform from the first and second waveform memory, respectively, and an envelope generator which generates two separate envelope signals. The first waveform including the attack portion of the musical tone and the periodic second waveform are multiplied by the separate envelope signals, respectively, and then the products of the multiplication are added together. The sum of the products is provided as an output.

Abstract: A first waveshape memory stores a full waveshape of a tone from the start to the end of sounding of the tone or a portion thereof in plural periods. A second waveshape memory stores waveshape data of a modification waveshape for the full waveshape or the portion thereof. A tone waveshape signal read out from the first waveshape memory and a modification waveshape signal read out from the second waveshape memory are both multiplied with respective coefficients whereby these waveshape signals are weighted. These weighted waveshape signals are added together to provide a mixed tone signal. By controlling the coefficients, the tone color imparted on the mixed signal is variously determined. The coefficients for the tone color control are provided in accordance with key scaling, key touch or operation states of control knobs. Thus, tone signals having a variety of tone color changes can be realized without the necessity of many wave memories.

Abstract: A keyboard operated electronic musical instrument is disclosed which has a number of tone generators that are assigned to actuated keyswitches. Musical tones are produced by computing a master data set from an interpolated sequence of harmonic coefficient values. The master data set points are read out sequentially and repetitively from a memory and converted into an audible tone. A plurality of harmonic coefficient memories are used to store preselected sets of harmonic coefficients. In response to a timing clock, the harmonic coefficients from a cyclically chosen pair of harmonic coefficient memories are selected. A tone having a time variant spectra is produced by using a time variant interpolation between the selected pair of harmonic coefficients.

Abstract: A keyboard operated electronic musical instrument is disclosed which has a number of tone generators that are assigned to actuated keyswitches. Musical tones are produced by computing a master data set which defines the data points corresponding to a period of a musical waveshape. The master data set points are read out sequentially and repetitively from a memory and converted into an audible musical tone. Circuitry is provided whereby the master data set is computed from a time sequence of harmonic coefficients which is modulated to produce a musical tone having a time variant spectra.

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: 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 audible musical waveform are transformed at an average rate corresponding to the fundamental frequency of the tone being generated, a computation means is provided to produce musical tones having an ensemble effect. The computation means comprises a multiplicity of interpolation calculations whereby a sequence of interpolated waveshape points are obtained from two different waveshapes whose data points are addressed from waveshape memories at different memory advance rates.

Abstract: In a musical tone signal generating apparatus of a harmonic combination system, the coefficient values of a continuous harmonic to be formed are discretely sampled. Among the sampled values, the values between each two adjacent sampling points (i.e., each two adjacent frames) which vary are selected, and only difference coefficient data therebetween are stored in a memory. When the harmonic coefficient data is to be formed, the difference coefficient data is used for the coefficient varying values between each two adjacent sampling points, and a new coefficient value is calculated. However, as for the nonvarying values between each two adjacent sampling points, no calculation is performed and an already calculated coefficient value is used, thereby updating harmonic coefficients as a function of time, and hence generating a musical tone signal whose tone color is changed as a function of time.

Abstract: The generating function cos[Z(t).multidot.sin(.omega.'t)] of Bessel functions is utilized as a modulating function for a fundamental function sin(.omega.t) in synthesis of a musical tone including many harmonic (over tone) components, wherein Z(t) is used as a modulating index. The modulating frequency .omega.' in sin(.omega.'t) of the modulating function cos[Z(t).multidot.sin(.omega.'t)] is selected relative to the fundamental frequency so that w'=n.omega. wherein n is a half integer or an irrational number.

Abstract: An electronic musical instrument capable of producing, by frequency modulation, a musical tone containing harmonic components of integer and non-integer orders at complicated ratios which change with time. In frequency modulation, amplitudes of carrier and side frequencies are preceded by a positive or negative sign depending upon a value of modulation index. By suitably setting the value of modulation index, phase inversion occurs in the side frequencies so that cancellation or augmentation of amplitude will occur between side frequencies of the same frequency. By utilizing this phenomenon and also the fact that the harmonic spectrum can be varied by varying the carrier and the modulating waves, the electronic musical instrument according to the invention produces a musical tone containing extremely complex harmonic components.

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: 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: In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, note-range 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.

Abstract: An electronic musical instrument includes a first memory in which audio samples of lower frequency components of an aperiodic waveform are stored and a second memory in which audio samples of a higher frequency components of the waveform are stored. Digital samples stored in a first portion of the second memory represent a rapidly rising portion of the higher frequency waveform and those stored in a second portion of the memory represent a rapidly declining portion of the higher frequency waveform whose amplitude and spectral energy distribution profiles are preferably equalized. The first memory is addressed throughout in forward scan to generate a first output waveform. The second memory is addressed in an initial forward scan throughout its first and second portions and the direction of scan is reversed at the end of the second portion to recyclically address it in rearward and forward directions to generate a second output waveform, which is combined with the first output waveform.

Abstract: Disclosed is a sound source apparatus which is composed of a plurality of sound component pattern generators each capable of providing a predetermined pattern, and a sound component picking circuit for sweeping the plurality of sound component pattern generators repeatedly in such a rapid sequence that the sound component thus provided and taken may constitute a musical sound at a desired pitch.

Abstract: In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, there is provided a musical waveform generator for caculating and synthesizing a temporally varying musical waveform at a plurality of sample points, memory circuits for storing two kinds of musical waveforms obtained by the musical waveform generator one after the other and an interpolation circuit for interpolating the two musical waveforms at time intervals shorter than the time intervals used in the musical waveform generator.

Abstract: In response to the data input from a keyboard, a tone clock generator generates a tone clock signal. The tone clock signal is counted by a waveform step counter. The output of the counter is used for making an access to a waveform memory. The waveform memory stores first and second waveform data of which the periods respectively are divided into a different number of addresses. One of the first and second waveform data read out from the waveform memory by the output of the counter is selected, according to the key-in data.

Abstract: A keyboard operated musical instrument is disclosed in which a musical tone having an extended range of harmonics is produced by combining two waveshapes at different fundamental frequencies. The first waveshape has a fundamental frequency corresponding to an actuated keyboard switch and has a spectrum containing a maximum of Q harmonics. The second waveshape is created by a single side-band modulation of two orthogonal musical signals each having a maximum of Q harmonics and has a phase coherence with the first waveshape. The second waveshape is generated at a frequency which is Q+1 greater than the fundamental frequency of the first waveshape. The first and second waveshapes are combined to produce a musical tone which has an extended range of harmonics.

Abstract: In a keyboard operated electronic 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 audible musical waveform are transformed at an average rate corresponding to the fundamental frequency of the tone being generated, a computation means is provided whereby the number of data words is varied adaptively with the fundamental frequency. The adaptive variation in the number of data points per waveshape cycle is accompanied by an associated adaptive variation in the maximum number of harmonics for the generated musical tone.

Abstract: A wave generating method and a wave generating apparatus using the method are arranged such that plurality of wave samples, each being generated successively, are respectively weighted by, for example, being multiplied by a plurality of wave functions generated corresponding to the plurality of wave samples. The plurality of weighted wave samples are summed to obtain a desired wave. The kind of each of the plurality of wave samples generated successively is changed at each time when the value of corresponding one of the plurality of wave functions becomes zero.

Abstract: A keyboard operated electronic musical instrument is disclosed which has a number of tone generators that are assigned to actuated keyswitches. Musical tones are produced by computing a master data set which defines the data points for a period of the musical waveshape. The computation uses a preselected set of harmonic coefficients. The time required to complete a master data set computation is reduced by dividing the set of harmonic coefficients into a number of subsets of coefficients. The harmonic coefficients are combined by a combination of a reverse addressing and complementing in a logic that decreases the required number of computation time intervals.

Abstract: A note ROM is addressed in response to a note code signal generated from a note code generator, and basic data is read out from the note ROM. The basic data is shifted by one higher bit and is thus doubled, and the shifted data is supplied to the A terminals of a full-adder. The basic data read out from the note ROM is supplied to the B terminals of the full-adder. The full-adder generates integer multiple data which has a value three times that of the basic data. This integer multiple data is decremented by one every time a clock is generated. When the integer multiple data becomes zero, a one-shot waveform data read clock signal is generated through an inverter.

Abstract: A digital filter imparting a desired tone color to the tone signal is realized by the combination of a digital pole filter and a digital zero filter capable of controlling a pole and a zero in an amplitude-frequency characteristic respectively. The amplitude-frequency characteristic of the digital filter is a composite of the respective characteristics of the pole filter and the zero filter. A "peak" portion and a "valley" portion in this composite characteristic can be set independently by the pole control of the pole filter and the zero control of the zero filter, whereby the desired tone color characteristic can be readily realized. Further, the digital filter may comprise a plurality of digital filters having respective different constructions and a connection switching circuit capable of setting arbitrarily connection between these filters. The filter characteristic as a whole can be diversely altered by changing the connection, whereby diverse tone color characteristics can be realized with ease.

Abstract: Apparatus and method for generating complex sounds having a more natural and agreeable quality wherein fundamental and higher order components may be uniquely and independently controlled to inexact integer relationships.

Abstract: A keyboard operated electronic musical instrument is disclosed which has a number of tone generators that are assigned to actuated keyswitches. Musical tones are produced by computing a master data set which defines the data points for a period of the musical waveshape. The computation uses a preselected set of harmonic coefficients. Provision is made for altering the harmonic coefficients to produce waveshapes which are derivatives or integrals of the basic waveshape. The order of differentiation or integration can be varied to produce time variant tone effects.

Abstract: This electronic musical instrument comprises digital tone generation circuits having a plurality of tone generation channels each being capable of selecting a tone color independently from other channels. In each of the tone generation circuits, digital tone signals having the selected tone colors are produced in response to operation of a key or a switch. A specific number of analog channels are provided for processing analog tone signals channel by channel and a channel divider is also provided for distributing the digital tone signals generated by the digital tone generation circuits to these analog channels in specific combinations according to the selected tone colors. This channel divider further mixes the distributed digital tone signals together for each of the analog channels for time-division-multiplexing the mixed digital tone signals for each of the analog channels. The multiplexed digital tone signals are converted to analog signals by means of a single digital-to-analog converter.

Abstract: An electronic signal X can have its envelope shaped by an electronic control signal Y. For music purposes, signal X can be an electronically generated note and control signal Y can be derived from the musician's voice. The signal shape controller exponentially modifies the control signal Y and multiplies signal X by the exponentially modified control signal Y to form an output signal having an envelope shape XY.sup.n. The exponent n has at least one value less than 1 applied to larger values of control signal Y and at least one value greater than 1 applied to lower levels of control signal Y. The controller also preferably includes an attack enhancement circuit to emphasize an attack portion of a control signal and a variable time integrator circuit that integrates the control signal over a short time interval when it is changing rapidly and over a longer time interval when it is changing slowly.

Abstract: A wave reading apparatus includes a wave generator for generating a plurality of wave signals, a read-out frequency generator for generating a plurality of read-out frequencies, a controller for controlling calculation, writing and reading of wave samples, a writing device, a plurality of buffer memories and a plurality of read-out devices. The controller informs requests of wave samples calculation to the wave generator in accordance with the read-out frequencies. The calculated wave samples are written through the writing device to the buffer memories and read out by the read-out device in accordance with the read-out frequencies, at least one of which is different in frequency from the remainder.

Abstract: A keyboard operated electronic musical instrument is disclosed which has a number of tone generators which are assigned to actuated keyswitches. Musical tones having an anharmonic overtones structure are produced by generating a number of component waveshapes each having a different fundamental frequency. These component waveshapes are summed to produce a single tone. Each component waveshape has a spectral content of a preselected subset of non-zero harmonic coefficients. The various components have mutually exclusive selection for the non-zero harmonic coefficients.

Abstract: A touch sensitive system for an electronic musical instrument providing a multiple key switch contact system for effecting control over two or more tone generating systems. The first tone generating system operating rapidly in response to the actuation of the key switch to produce a desired voice. The second or subsequent tone generating systems operate sequentially in a delayed manner on the actuation of the key switch effecting a predetermined delay in the production of the desired voice. The audio output of each of the tone generating systems is summed forming a resultant waveform for audio amplification. The key switch actuation, depression and release, causes the tone generating systems to respond immediately to the depression or release of the key switch which effects a change in the envelope characteristics of the resultant waveform.

Abstract: A keyboard operated electronic musical instrument in which a number of tone generators are assigned to actuated keyswitches in which a combination of a transient voice and a steady state tone is generated by implementing a discrete Fourier transform employing a selected sequence of harmonic coefficients. A harmonic sequence select logic in cooperation with signals from actuated tone switches provide the selected sequence of harmonic coefficients. A percussion coefficient is added to the sequence of harmonic coefficients in response to a percussion control signal. Various playing modes are disclosed. In one mode the transient voice is generated with the actuation of the first keyswitch on a selected keyboard, and other subsequent actuations are ignored. In a second mode, a transient voice is actuated if at the time of a keyswitch actuation no other transient voice is being generated.

Abstract: Frequency information is stored in a tone coefficient memory and accumulated to obtain address information for reading out a musical sound from a musical waveshape memory by a musical sound generating circuit. Envelope information is stored in an envelope coefficient memory and accumulated to obtain address information for reading out an envelope waveshape from an envelope memory by an envelope generating circuit. An address counter performs address assignment for operating the musical sound generating circuit and the envelope generating circuit on a time-divided basis. The frequency information and the envelope information are respectively accumulated by a common accumulator on the time-divided basis. Further, attack and decay coefficients are stored in the envelope memory by higher and lower order bits of the same address, respectively, and the contents of the higher and lower order bits are selectively read out.

Abstract: An electronic musical instrument which produces a musical sound by controlling harmonics coefficient and using computing means based on the discrete Fourier transfer. For a fundamental wave, a period function indicated by predetermined period data is generated and, for a harmonic wave, a period function of a period having a predetermined relation to the period of the fundamental wave is generated. By the period function thus obtained, a modulating waveshape memory is read out to obtain modulating data, which is multiplied by a harmonic coefficient.

Abstract: For controlling the blend between two pickups on an electric guitar, this circuitry provides, over the range of a single simple potentiometer, continuously variable blend between the two pickup signals in a particular phase relationship plus continuously variable blend of the two signals in a reversed phase relationship, eliminating the use of phasing switches, and providing musicians with a wide range of tonal variation under continuous control, for freedom of musical expression and timbre modification not available heretofore. Implementation with operational amplifier integrated circuits facilitates further processing of each pickup signal independently for special effects such as the introduction of controlled distortion.

Abstract: A sound aspect generating apparatus for an electronic musical instrument is adapted to interpolate between respective parameters constituting two kinds of designated sound aspects to generate sound aspects based on the interpolated parameters. More specifically, preset switches (71 to 7n) are operated to read out the parameters of the two kinds of sound aspects stored in advance in a memory (50). By designating an arbitrary point between two kinds of sound aspects with the aid of a controller (10), the rate of change of the respective parameters between the designated sound aspects is evaluated by means of a central processing unit (40) and the parameters interpolating the portion between the designated two points are evaluated by the central processing unit based on the above mentioned rate of change. The evaluated parameters are converted into an analog signal which is applied to a music synthesizer as sound aspects, whereby a musical tone signal is produced.

Abstract: The present invention is a differential sampling circuit for improving the signal to noise ratio by eliminating d.c. level distortion in square wave signals used as components for forming a stairstep or bright wave signal in an electronic organ having multiplexed keying. The multiplexed drawbar signals for even footages at both sides of a sampling resistor are demultiplexed, applied to a sample and hold circuit and applied as inputs to a differential amplifier to cancel any fluctuations of the d.c. signal component.

Abstract: A keyboard operated electronic musical instrument is disclosed which has a number of tone generators that are assigned to actuated keyswitches. Logic is provided for generating a note range signal for each preselected group of contiguous keyswitches in which the note range signal is selected for an actuated keyswitch. Musical effects such as vibrato and tone changes are selectively actuated in response to the note range signal. A mixture tone generator is described which uses a single set of harmonic coefficients which are translated and shifted in response to the note range signal.