Abstract: An electronic musical instrument comprises a waveshape memory delivering out digital value samples of one cycle of a certain waveshape, and a loop circuit including a filter and a shift register. The digital waveshape values read out from the waveshape memory is caused to circulate at a predetermined rate of time in the loop circuit. A waveshape taken out from the loop circuit varies as time lapses, and is utilized as a musical tone.

Abstract: Pedal control circuits for use with an electronic musical instrument, such as a piano, which provide control functions analogous to the actions of a sustaining pedal, of a sustenuto pedal, and of a volume pedal of a conventional piano. Damper circuits operable in conjunction with a sustaining pedal provide an effect analogous to the action of the sustaining pedal in a conventional piano, a latching circuit actuated by depression of a sustenuto pedal operates in conjunction with the damper circuits in a manner analogous to the action of a sostenuto pedal in a conventional piano, and a volume pedal and associated circuitry is operative to determine the level of the output tones only at the moment of strike of the keys, an action analogous to that of the volume pedal in a conventional piano.

Abstract: An electronic musical instrument has a plurality of tone selectors which select musical tones; a waveshape calculator which calculates a waveshape represented by amplitudes at two or more than two sampled points of one period of the selected tone and which is operative whenever the tone selectors are actuated; a plurality of waveshape memories which temporarily memorize the calculated waveshapes; clock signal generator which generates clock signals with high frequencies corresponding to pitches of depressed keyswitches of the musical instrument and which is operative whenever the keyswitches are depressed; a reading circuit which repetitively and successively reads out the memorized waveshape amplitudes by the clock signal generated by the clock signal generator; and a converter which converts the waveshape amplitudes read out by the reading circuit to a musical tone, wherein a musical tone is generated by repetitively reading out the temporarily memorized musical waveshape.

Abstract: In a touch-responsive circuit adapted for use in an electronic musical instrument provided with a keyboard, and comprising a key depression speed detector including a change-over switch, a capacitor for storing electric charge and a discharging resistor, and a controlling signal generating means including a gating transistor controlled by the key depression speed detector and another capacitor for storing electric charge through said transistor, a voltage-compensating element is connected in the key depression speed detector so as to compensate for the threshold voltage of the gating transistor thereby raising the minimum output voltage of the key depression speed detector and insuring the sound generation for the pianissimo performance.

Abstract: A phase shifter circuit in electronic musical instruments, in which sound effects are generated by varying the amount of phase shift through voltage control. The amount of a shift may be linearly varied by an external voltage, and the operating point of the phase modulation can be freely set over a substantially wide range. The amount of phase shift, furthermore, may be made large so that a circuit stage having a pair of transistors is designated as a unit, and several such units are cascode-connected. Adjustment of this unit is not required.

Abstract: The system comprises a frequency number memory device for storing information regarding the frequencies of respective tones, a keyboard switch for reading out frequency number information corresponding thereto from the memory device, an address generator including an adder for adding a predetermined number of the frequency number information thereby producing an address signal consisting of plural bits, address composers for processing the bits of the address signal and thereby composing digital tone signals constituting a saw-tooth, square and triangular waveshape, and digital-analog converters for converting the digital tone signals into analog tone signals, which are thereafter used to synthesize waveshapes of any tone.

Abstract: A digital musical instrument incorporating the effects of attack and decay by appropriately scaling the digitally synthesized waveform information at the leading and trailing portions of the waveform envelope. Such an instrument would be capable of producing two attack and decay periods with only one attack and one decay period resulting in the normal audible effect. The system is particularly adapted for use in an electronic musical instrument in which a digital multiplexed signal is generated by actuation of the keys of the instrument. The attack and decay periods generated by actuation and deactuation of the keys are processed such that each period is divided into "n" scale factors spaced in time, each such scale factor being associated with a different level of the waveform envelope. The scale factors cover the range of waveform envelope from zero to full scale. Upon receipt of a clear pulse, the digital counter begins counting, and would terminate the count upon reaching "n".

Abstract: A channel processor capable of assigning a key code provided by a key coder and representing making (or breaking) of a key switch to one of a plurality of channels for storage therein and subsequently detecting breaking (or making) of the same key switch on the side of the channel processor. The assignment of the key code is implemented by holding the key code provided by the key coder during a predetermined period of time, detecting whether conditions for the key code assignment have been satisfied or not in a former half of the holding period and, if such conditions have been satisfied, causing the key code to be stored in an empty channel of a main memory device in a latter half of the holding period. Detection of breaking of the made key switch (or vice versa) is made by once clearing a memory storing the assigned channels by means of a start code generated by the key coder and subsequently finding that a channel among the cleared channels is not stored in the memory again, i.e.

Abstract: Electronic musical tone generating methods and apparatus such as electronic organs and music synthesizers are described. An impulse response characteristic of the tones is represented by digital signals which are stored at different locations in a digital memory device. The memory is read out repetitiously at selected rates to produce tones of selected frequency or pitch (different notes of the musical scale). The interval during which the stored impulse response is read out is varied in order to generate the tones with different timbre such that different musical instruments (the stops in the electronic organ application) may be emulated.

Abstract: An electronic musical instrument has a keyboard equipped with apparatus for developing a voltage in response to the momentum of operated keys of the keyboard, which voltage is employed to control the amplitude of the sounds produced in response to each key depression. The amplitude is dependent partially upon the momentum of the key depression and partially upon the amount of time since the previous depression of the same key. An envelope generator operates in response to depression of a key and has a charge circuit for controlling attack and decay of the envelope. The discharge circuit is controlled partially by the pitch of the note selected by the depression of any given key of the keyboard. The envelope produced by the envelope generator controls a unit which functions as a combined modulator and filter, closing a path between an audio source and an output system and varying the width of the band-pass provided for the signal from the audio source in response to the amplitude of the envelope.

Abstract: In an electronic musical instrument of the type having keys, a system for controlling the volume of the sound produced by the instrument when the keys are depressed or struck. For each key, the system comprises a tone generator, a gate coupled between the tone generator and the speaker of the instrument; and control means for producing a control signal having an amplitude which is a function of the speed at which its associated key is moved while being depressed. The control signal is applied to the gate to pass the output of the tone generator to the speaker and to control the volume of the sound produced by the speaker.

Abstract: A circuit for providing a predetermined contour for the audio signal produced by an electronic musical instrument. A reference potential which is changed under predetermined conditions, and an unidirectional reference current which may also change under some or all of the predetermined conditions, are applied to a circuit which changes the amplitude of the audio signal from its existing level to a level determined by the reference potential at a rate which is determined by the reference current.

Abstract: A delayed vibrato signal generating arrangement comprises an envelope signal generator having a capacitor, a switching device for discharging the capacitor at the instant of key depression, and two charging circuits providing different charging time constants for charging the capacitor to produce an envelope signal; a semiconductor unidirectional device coupled to the envelope signal generator; and a vibrato signal generator coupled to the unidirectional device. The capacitor is relatively rapidly charged to a predetermined potential level by both the two charging circuits and then gradually charged by only one of the charging circuits. The signal portion of the envelope signal substantially below the predetermined potential level is clipped off by the unidirectional device to provide a time delay for delayed vibrator. The time delay is virtually determined by the time constant for charging the capacitor to the predetermined potential level.

Abstract: An electronic musical instrument capable of controlling tone pitch, tone color, volume etc. of a musical tone by a sliding operation to conduct such on effect as portamento. The instrument according to the invention can produce a control signal proportional to a sliding distance on a portamento playing actuator regardless of an initially touched position on the actuator. For producing such control signal, an output voltage from a portamento playing actuator corresponding to a finger touch position is applied to a positive input of a calculator whereas a voltage obtained by sampling and holding an output voltage corresponding to the initial touch position is applied to a negative input of the calculator. Difference between the two voltages is outputted as a control voltage from the calculator and this control voltage is utilized for controlling VCO, VCF or VCA thereby to control the tone pitch, tone color, volume etc. of a musical tone.

Abstract: A control voltage waveform generator is provided with a voltage-controlled variable resistor, a storage capacitor forming a time constant circuit together with the resistor, a plurality of voltage signal sources, and a plurality of time constant determining voltage signal sources. The voltage signal sources are sequentially coupled to the storage capacitor through the voltage-controlled variable resistor, and the time constant determining voltage signal sources are sequentially coupled to the control input of the voltage-controlled variable resistor.

Abstract: An electronic musical instrument is of a type wherein an envelope to be imparted to a musical tone is stored in a memory as its sampled values and sequentially read out to constitute an envelope shape. A key depression causes the read-out of the memory.The instrument is improved to provide a rich sound effect of legato performance by successively and smoothly shifting the tone of the former key to that of the latter key while maintaining a predetermined constant tone volume. This legato effect can be carried out by successively maintaining the sustain level of the musical tone envelope from the tone of the former key shifted to the latter key. The musical tone envelope is read from the envelope memory by an address which is shifted by a clock pulse.

Abstract: The circuits described herein are particularly applicable to organs using multiple pitch divider type note generators that are implemented in LS1 form, since one of the aims of the improvements is to reduce the pin count of the LSI chips required in these organs. One such circuit is a synchronizing system used to phase corresponding notes generated in different chips over a single multiplexed buss. Another multiplexed buss is used to identify the lowest octave in use for each note of the chromatic scale. A new touch response circuit employs a digital to analog converter to eliminate the need for capacitors used in previously described fully analog type circuits thereby eliminating many pins. This circuit furthermore enables a superior relation of key velocity to signal level to be obtained which makes practical a wider dynamic gradation of sound.

Abstract: The electronic musical instrument according to the invention is capable of controlling each level of harmonics constituting a musical tone individually and independently from each other and thereby producing a musical tone which is a close simulation of a natural musical tone. In order to produce change in the level of each harmonic with the lapse of time separately and independently, information respectively representing a peak level of attack, attack time from start of generation of a tone to the peak level, a sustain level and decay time from the peak level to the start of the sustain level is memorized for each harmonic and the level of each harmonic is controlled in response to such information.In one example of the electronic musical instrument, the level of each harmonic constituting a musical tone is amplitude-modulated with a different period and depth.

Abstract: A single amplitude curve generator is time shared amongst a plurality of musical tone generators for controlling their musical shapes. The curve generator creates a wide variety of envelope characteristics by implementing a recursive computation algorithm for selected choices of a single curve shape parameter coupled with the use of a collection of timing clocks used to vary the time intervals associated with the attack, decay, and release regions of the musical tone envelope. Provision is made for forcing the release of a tone generator when a limited number of tone generators have been completely assigned in a keyboard musical instrument and a new note key switch is actuated. Note release signals can be ignored until the amplitude curve generator has completed the attack and decay regions for a given tone generator.

Abstract: A tone-generating system for an electronic musical instrument of the percussion type is provided wherein an audible tone closely approximating the corresponding tone of a conventional instrument is generated electronically. A single-pole, double-throw switch is actuated by a key to initiate generation of the tone and a tri-level detecting circuit coupled to the switch is utilized to determine which of the three states the switch is in; that is, the two "throws" or positions of the switch which correspond to the released and depressed positions of the key, and the state in which the switch is between the other two positions. By detecting the three states and developing corresponding control signals, counting circuitry may be utilized to determine the intensity with which the key is depressed to enable generation by a read-only memory of digital scaling signals representative of the variations in amplitude of the initiated tone with respect to the intensity with which the key is depressed.

Abstract: An electronic musical instrument having a plurality of frequency sources driving a plurality of waveshape controlling circuits rendered operative by a plurality of keyswitches comprising a keyboard to produce polyphonically, organ voices, piano and harpsichord voices, accordian voices, and other voices characterized by changing harmonic structure as the key is held down.

Abstract: A monophonic system includes means for voicing only tones derived in response to depression of a key associated with the highest pitched note when several keys are struck at approximately the same time, regardless of the order in which the keys are struck. If several keys are released at approximately the same time, only the tones derived in response to the highest remaining activated key are voiced, regardless of the release sequence. In response to the system being played legatissimo, voiced tones gradually shift in frequency, i.e., portamento is achieved. In response to the system being played staccatissimo, voiced tones shift in frequency in discrete steps.

Abstract: An electronic music synthesizer is disclosed in which the sound producing chain includes a voltage-controlled oscillator, band-pass filter, low-pass filter, and amplifier in which selected control currents are supplied to low impedance points within the synthesizer circuit from a resistor matrix. The synthesizer produces sounds approximating different acoustic musical instruments or having different tonal qualities by the application of a predetermined voltage to one of fifteen input columns of the resistor matrix with selected other columns being grounded. The currents provided by the resistor matrix in combination with other externally generated currents control the center frequency and bandwidth of the band-pass filter, the cutoff frequency of the low-pass filter, the gain of the voltage-controlled amplifier, the time constants of transient contour currents used to control the filters and amplifier, and the waveform produced by the voltage-controlled oscillator.

Abstract: Touch responsive control of note amplitude and harmonic content is achieved by providing each key with a touch responsive transducer. A set of attack/decay scale factors are accessed sequentially from a memory and used to establish the amplitude envelope of the generated note. The accessed scale factors are modified by the transducer output to effectuate touch responsive amplitude control. In a preferred embodiment, scale factors stored in consecutive memory locations define a piano-like attack/decay envelope. The transducer output sets the initial memory access location, so that the harder the key is struck, the greater the initial amplitude of the generated note.Other embodiments include touch responsive control of the constituent Fourier components of the generated tone; and utilization of multiplexing for time shared connection of plural analog touch responsive transducers to a single analog to digital converter.

Abstract: An improved gate circuit to suppress bounce is provided for an electronic musical instrument such as an electronic organ. The circuit includes a gate having a first input from a constant supply voltage through a key actuated switch, a second input comprising a sound signal and an output connected to one input of combining or summing circuit hereafter called an integrator. A second input to the integrator comprises a constant, compensating voltage comprising a portion of the supply voltage. The output of the integrator is connected to further processing stages of the instrument.

Abstract: A synthesizer type electronic musical instrument in which a volume envelope imparted to a tone signal decays with a decay time after release of a key. In such an electronic musical instrument, the decay time of the volume envelope is caused to vary according to the note of the key being actuated. As a decay time controlling signal, a pitch determining voltage signal is applied to a control voltage generator for a voltage-controlled amplifier, or is adapted to control a control voltage from the control voltage generator so that the control voltage may be of a waveform having a decay time which depends on the magnitude of the pitch determining voltage signal.

Abstract: The electronic musical instrument according to the invention produces excellent tone color effect by changing filter characteristics discontinuously from the start of generation of a musical tone.A plurality of filter characteristics each represented by a deflecting line consisting of straight lines (these filter characteristics being different from each other in coordinates at each point of deflection as well as inclination of each straight line) are stored in memory. These filter characteristics are sequentially read out with the lapse of time and level information of each harmonic constituting a musical tone is obtained by calculating a primary functional formula of the straight line region in which the read out filter characteristic belongs. The level of each harmonic is controlled in response to this level information.

Abstract: A tone source apparatus is provided for an electronic musical instrument. It comprises a memory circuit which has a plurality of addresses and is so arranged that where at least one cycle of a musical tone waveform is divided into p units and a waveform in each section range is represented by a formula containing the abscissa as its variable, a coefficient and a section range quantum number of each formula is memorized in the form of digital signals in the corresponding address. Also included are a clock pulse oscillator, a counter means for counting output clock pulses of the clock pulse oscillator, and a coincidence circuit serving to generate the coincidence signal when the output digital signal of the counter means and a digital signal of the section range quantum number memorized in the memory circuit coincide with one another. A decoder designates the next stage address in order by output signals of the coincidence circuit.

Abstract: A musical instrument includes a multiplicity of circular endless magnetizable tapes with a plurality of different tracks, a multiplicity of pick-up heads for each of the tracks and a multiplicity of variable-gain amplifiers connected to the tracks, respectively. Keys having respective contact means for energizing each of the amplifiers, cause a multiplicity of magnetic elements to generate respective voltages in coils, each voltage being proportional to the force with which an individual key has been depressed. This voltage sets the gain of a respective amplifier, so that the loudness of a recorded tone heard is proportional to the actuating force of a key.

Abstract: This invention provides an electronic musical instrument capable of producing plural musical tones simultaneously and also capable of controlling the pitch, tone color and volume of the musical tones in response to a player's finger touch on a key.Transducers capable of electrically detecting the finger touch, i.e. factors including pressure and speed of depression and displacement of the key, are provided for respective keys. Analog outputs of these transducers are sampled and multiplexed in time sharing by each of channels of the number equal to a maximum number of musical tones to be produced simultaneously, and each of the multiplexed signals is held in a corresponding one of condensers provided in the respective channels. The pitch, tone color and volume are controlled in accordance with the magnitudes of voltages held in these condensers. Suitable discharging circuits are connected to these holding condensers.

Abstract: A digital keying system for an electronic organ comprises a voltage divider network consisting of weighted value resistors switched into or out of the circuit by corresponding switches. The network is connected to a tone signal output terminal, and a circuit is connected to control the states of conduction of the switches. Closure of a key-operated switch or the presence of a pulse in a predetermined time slot in a digital multiplex signal train causes clock pulses from an attack clock pulse source to be applied to the control circuit to selectively control the operation of the switches to shape the attach waveform of tone signals appearing on the output terminal as determined by the pattern of operation of the switches.

Abstract: A percussion processor for an electronic musical instrument, such as an electronic organ in which information representative of the actuation of selected switches corresponding to associated notes of the musical scale is furnished in the form of a time-division multiplexed signal having repetitive sequences of time slots, includes a delay circuit comprising a shift register having a time delay period equal to the duration of one of the sequences of time slots or an integer multiple thereof. The multiplexed signal train is applied to the delay circuit and also is applied in parallel to an inverter circuit. The output of the inverter and the output of the shift register are connected to different inputs of a NAND gate.

Abstract: A rhythm unit produces repetitive pulses having one of a plurality of selectable predetermined time relations to each other for use as rhythm or accompaniment signals in an electronic organ or the like. Each of the pulses triggers operation of a modulator for modulating accompaniment tones in time with pulses produced by the rhythm unit, in correspondence with a programmed pattern. The shape of the modulated envelope waveform, its amplitude, and its frequency composition are programmed in accordance with a prearranged sequence, to give the desired sound characteristic within each of a plurality of individually selectable rhythms.

Abstract: An electronic muscial instrument capable of calculating level information of slope portion of a filter characteristic on the basis of the inclination of the slope and the cut-off frequency without requirement of storing level information of the slope portion for each individual frequency.The inventive electronic musical instrument is also capable of obtaining level information of an acute portion of filter characteristic which constitutes selectivity Q by calculating the inclination and peak value of the acute portion and difference between the peak frequency and the cut-off frequency.An example is shown in which the cut-off frequency is caused to successively change during a period of time from the start to the end of playing of a musical tone and in which the peak of the selectivity Q can be directed either upward or downward as desired.

Abstract: A modulator for modulating an audio signal in response to a dc signal of adjustable level and concurrently in response to a sub-audio signal, in which the modulating signals do not appear in the output of the modulator nor intermodulate each other, the system including transistor pairs which respond differentially at the bases to the modulating signal and additively to the audio signal in response to application of the audio signal at the emitters.

Abstract: An electronic music synthesizer including a keyboard control system for enabling multiple independent voice channels (voices) to be controlled by the keyboard in a musically pleasing manner. The control system responds to a keyboard of M keys to control N voices where N<M; e.g. M=64 and N=10. The voice channels are preferably identical to one another, each being comprised of voltage controlled elements such as an oscillator (VCO), amplifier (VCA) and filter (VCF). Typically, the control system selects an available voice channel and in response to a key depression, supplies a DC control voltage thereto whose level is nominally linearly related to the note corresponding to the depressed key. In addition to the control voltage, the control system supplies a gate signal to the selected voice channel indicating the time duration of the key depression.

Abstract: A music synthesizer produces pitch-proportional voltages in a novel resistor network, uses these voltage via keyboard control to generate in a voltage-controlled oscillator a high frequency signal, being a multiple of all the harmonic frequencies desired, separates the individual harmonics, converts them to sine waves with voltage-controlled tunable tracking filters, blends the waves in desired proportions, introduces transients of attack, decay, sustain, and release of key into each note, and introduces appropriate vibrato. An alternate apparatus accepts an external signal and converts it to voltages proportional to frequency, whereby accompaniment on pitch, in "close harmony" or more distantly related, is provided.

Abstract: A separate group of function preset controls is provided for each of a plurality of individually adjustable functions, to select predetermined values for such functions or, alternatively, to allow manual adjustment thereof. A supervisory preset control is provided for controlling the operation of several different function preset controls, in accordance with an overall plan including predetermined settings for a plurality of functions. In one mode of operation of the supervisory preset control, each of the function preset controls is placed in its manually adjustable mode, so that the individual functions are all controlled by manual adjustment. In other modes of operation, each of the function preset controls is placed in one of its fixed modes, to establish a predetermined fixed combination of function settings.

Abstract: A digital keying system for an electronic organ comprises a voltage divider network consisting of weighted value resistors switched into or out of the circuit by corresponding switches. The network is connected to a tone signal output terminal, and a reversible counter is connected to control the states of conduction of the switches. Closure of a key-operated switch causes clock pulses from an attack clock pulse source to be applied to the reversible counter to selectively control the operation of the switches to shape the attack waveform of tone signals appearing on the output terminal as determined by the pattern of operation of the switches. Upon release of the key, clock pulses from a decay clock generator are applied to the counter to operate it in the reverse direction, establishing a decay envelope for the tone signal in accordance with the pattern of operation of the switches.

Abstract: A plural mode envelope generator in which a basic time constant circuit is coupled by selector switches to a plurality of envelope generating means which function under the control of one or both of a keydown detector and a legato pulse generator. Fast attack-short substain and slow attack-long sustain envelope circuits involve standard techniques. A dual mode percussion circuit provides post key release sustain in one mode when the keydown detector is decoupled from the circuit and post key release tone snubbing when the keydown detector is coupled to the circuit. A sostenuto circuit with flip-flop latch includes a reset gate to hold the flip-flop in reset until sostenuto keying is desired whereupon a unidirectional circuit couples the initial keydown signal to the latch to place the flip-flop in a set state but prevents the disappearance of that signal from resetting the latch.

Abstract: An electronic Zimbelstern system in which a sequential counter actuates a set of self-damping circuits in a predetermined repeating sequence, the self-damping circuits each enabling a different set of sinusoidal tone sources in such relative amplitudes and with such relative rise and decay envelopes as to simulate the sounds of sequentially sounding bells of diverse fundamental frequencies when electro-acoustically reproduced.

Abstract: A new, performer played, real time, multitonal, multimbral musical instrument consists of speed and force sensitive keys in which time domain multiplexing is used to find and associate one and only one tone generator, not otherwise busy, with any key that is depressed. The sound generator disclosed can provide very realistic simulations of the flute, oboe, trumpet, French horn, trombone through the provision of various types of modulations in amplitude and frequency of the various partials, as is characteristic of each instrument simulated, and filtered noise. Glissandi are provided from one note to another and are controlled from the pair of keys involved by the relative pressure with which they are depressed. For the nonpercussive tonalities, the speed with which a key is depressed, which is determined by differentiating the force, may be used to cause the attack transient to behave in a manner very characteristic of the instrument being simulated.

Abstract: When a beating force is applied to a beat plate having a magnet attached to the lower surface thereof, an output responsive to the strength and application speed of the beating force is produced in a sensing means comprised by a Hall element disposed below the magnet. The output is used for controlling an oscillation circuit for generating a percussion instrument sound signal and an output therefrom is converted into a percussion instrument sound by means of a speaker.

Abstract: An electronic musical instrument comprising a voltage controlled oscillator, a voltage controlled filter, a voltage controlled amplifier and envelope generators. An output envelope of the envelope generator has various parameters such as rise time and decay time or times. The envelope generator is of the voltage controlled type so that the parameters of the output envelope of the envelope generator are controllable in response to parameter controlling voltages from a parameter controlling voltage generator. In an attempt to enhance performance effects a switch circuit is provided, in accordance with the invention, to interchange between a rise time controlling voltage and a decay time controlling voltage which are both coupled from the parameter controlling voltage generator to the envelope generator.

Abstract: Timing signals of adjustable rate are estabilished digitally in an electronic musical instrument through the use of digital timing numbers. A selected one of such numbers is repetitively added to the contents of an accumulating adder at a fixed rate. A train of timing pulses is obtained from one bit output of the adder; the rate of these pulses is directly related to the value of the selected timing number. Alternatively, consecutively updated parallel bit timing codes can be obtained from plural bit outputs of the accumulating adder. These timing codes, which are incremented or decremented in value by amounts established by the selected timing number, are useful for directly addressing a memory containing a set of musical instrument factors that are to be utilized on a time dependent basis.

Abstract: An electronic musical synthesizer generates tone signals coupled to a controllable bandpass filter and a controllable low-pass filter. A plurality of voice switches are individually selectable to couple preset control voltages to the filters, and to enable potentiometers which can be adjusted to generate control voltages to vary the frequency characteristics of the filters, control the octave of the tone signals, and to control a modulation oscillator. When a variable/preset switch is set to a preset state, the potentiometers are disconnected and auxiliary sections of the selected voice switch presets voltages for the oscillator, the octave circuit and the filters.

Abstract: An automatic music playing system including a matrix circuit and manual play switches both connected to tone signal generators, each of said manual play switches consisting of a series connection of a resistor and a switch and a capacitor connected between the interconnection of said resistor and switch and the input terminal of a corresponding tone signal generator so that the output signals of said matrix circuit is absorbed in said capacitor when said switch is closed and an on-off switch operation triggers the corresponding tone signal generator, and each of said tone signal generators including two oscillating transistors connected with a feed-back loop and provided with a damping resistor.

Abstract: A Zimbelstern system or sequential bell ringing system in which a sequential counter actuates a set of self-damping circuits in a predetermined repeating sequence, the self-damping circuits each enabling a different set of sinusoidal tone sources in such relative amplitudes and with such relative rise and decay envelopes as to simulate the sounds of sequentially sounding bells when electro-acoustically reproduced.

Abstract: Disclosed is an electronic piano circuit arrangement which combines a multitude of different frequencies within a resistordiode matrix array. The resistor-diode coupling elements provide a different value impedance for various signals to be combined and the amplitude of the signals are predetermined to electronically produce a piano sound which substantially corresponds to the sound of an actual piano tone.

Abstract: The embodiment of the invention disclosed herein is directed to an electronic musical instrument of the keyboard type used to electronically reproduce piano sounds. The circuit has means to vary the amplitude of the piano voice in response to the velocity of the downward movement of the key. Means are provided for producing a fundamental square wave frequency and the second and fourth harmonics thereof, in response to the actuation of a given key on the keyboard. One circuit arrangement includes means for combining the fundamental frequency and the second and fourth harmonics in a predetermined time relation to produce the zero, attack, peak, and decay characteristics of a piano voice as actually produced by a piano string.