Abstract: A sound effect circuit with a phase shifter producing a signal shifted in phase with respect to an input signal, a combining circuit for arithmetically combining the input and phase shifted signals to produce an output signal, an oscillator for periodically modulating a characteristic frequency of the phase shifter and a modulation control circuit. The modulation control circuit causes the modulation rate to gradually increase when modulation is manually switched on and to gradually decrease when modulation is switched off. The modulation control also causes the characteristic frequency to vary inversely with the modulation rate.

Abstract: A register arrangement is provided for an electronic musical instrument (such as an electronic organ) whereby the various functional units of the instrument are actuated by electronic selector switches each one of which in turn has a control conductor to which control voltage can be applied by a register assembly either individually or as part of a preselected grouping of functional units.

Abstract: An arpeggio circuit for an electronic organ employing digital encoding, decoding and code conversion techniques to semiautomatically generate an arpeggio effect composed of tone signals having an octaval relationship and corresponding to selected note keys held down on an accompaniment keyboard. The rate of generation and order of the arpeggio tone signals is controlled by means of a plurality of manually actuatable arpeggio control switches. A plurality of individually identifiable control signals are sequentially generated in response to sequential actuation of the plurality of control switches. The control signals are binarily encoded. Tone signals provided by a set of tone generators are selectively associated with appropriate ones of the encoded control signals by a tone selector circuit which provides the selected one of the tone signals to an arpeggio output tone signal generating circuit when the associated encoded control signal is being generated.

Abstract: In a voicing system for electronic organs, square wave signals from a tone generator are converted to a waveform of another shape, the harmonic structure of which is useful for producing certain organ voices. This modified waveform is further modified, as by integration or differentiation, to produce signals of yet another wave shape whose harmonic content makes it useful for deriving still other organ voices. In one embodiment, the square wave pulses are initially converted to narrow pulses which are particularly suitable for the production of reed and certain string voices, and these sharp, narrow pulses are integrated to produce, in effect, a separate source of signals having a sawtooth waveform the harmonic structure of which is particularly suitable for production of cello, diapason and flute sounds.

Abstract: A keyboard operated tone synthesizer with portamento effect in which each key controls the pitch of the generated tone through a table of frequency numbers, each key selecting a corresponding frequency control number from the table and converting this number to an analog voltage which is applied to a voltage controlled oscillator, the oscillator in turn controlling the pitch of the associated tone generated by the synthesizer. The portamento effect of having the pitch of one note slide smoothly into the pitch of the next note is achieved by subtracting the frequency number of a new note to be generated from the frequency number controlling the frequency of the note currently being generated. A fraction of the difference is stored in an increment register and added over and over to the frequency number of the current note at a controlled rate until the frequency control number equals the frequency control number of the new note.

Abstract: In an electronic musical instrument of the class wherein the amplitude samples of a tone at successive sampling points of musical tone waveform are calculated by independently calculating respective partials that constitute the musical tone waveform and then adding the calculated partial samples, there are provided a "variable" generating circuit which generates a variable which varies with time, and a "variable" modifying circuit which modifies the variable with a coefficient corresponding to each partial thereby independently modifying the normal frequency of each one of the correponding partials in accordance with the output from the variable modulating circuit.

Abstract: A volume control arrangement for an electro-acoustic system, said arranget having an adjustable amplification factor and a frequency characteristic dependent thereon, and comprising a frequency selective circuit which has an amplitude/frequency characteristic curve having at least one maximum lying within the audio frequency range and equivalent to the pass range of a band filter, and a circuit arrangement for varying the frequency and amplitude of the maximum in dependence on the adjustment of the amplification factor.

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: An electronic echo device comprising an input amplifier, an output amplifier connected therewith across a transfer channel, a delay device connected in parallel to said channel, and a feedback path connected in parallel to said delay device. According to this invention a control device is included between the input of the echo device and the delay device, to which control device the feedback path is also connected. The arrangement is such that the gain factor of the control device, upon a relatively sudden change in the signal level supplied to it, varies to counter-act said change.

Abstract: An automatic rhythm performing apparatus comprises a voltage-controlled variable frequency clock generator, a plurality of tempo determining voltage signal sources, a selector for selectively coupling one of the tempo determining voltage signal sources to the clock generator, and an automatic rhythm generating circuit including a counter for counting clock pulses from the clock generator and generating a rhythm in response to the clock signal. The tempo of the rhythm produced by the rhythm generating circuit is dependent upon the magnitude of a tempo determining voltage coupled to the clock generator. A control circuit having a foot switch and a rhythm start switch may be provided to control the selector and counter. The counter is enabled to count the clock pulses by the operation of the rhythm start switch. The operation of the foot switch causes the counter to be disabled or causes the tempo determining voltage source coupled to the clock generator to be switched from one source to another.

Abstract: An electronic music box circuit is provided which includes a pulse generator, a read only memory having address lines to be energized in a predetermined order by the output pulse signals from the pulse generator and memory cells arranged in accordance with a given melody, and a frequency-divider which divides the frequency of the output pulse signal from the pulse generator to produce a plurality of signals with different frequencies. In the read only memory, when one of the address lines is energized, a musical scale signal selection circuit and a signal level selection circuit are energized so that an output signal with a frequency selected from the output signals of the frequency divider is generated from the scale signal selection circuit while at the same time an output signal with a selected signal level is generated from the level selection circuit. The output signals from the scale signal and level signal selection circuits are supplied to a loudspeaker thereby to generate a predetermined sound.

Abstract: A pipe organ in which the operative condition of keys and stops is examined by time-division multiplex techniques to provide digital signals which can be transmitted to a pipe sounding section of the organ and/or recorded for subsequent transmission to the pipe sounding section of the organ, note/stop correlation between keys played and pipes to be sounded being effected by modification of the transmitted digital signals.

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: In this monophonic pedal or truncated decay system, depression of a new pedal key immediately truncates tone production of a previously played, decaying note. If two notes are played simultaneously, both will sound until one is released, whereupon that tone will be truncated immediately without decay.The inventive system operates with a time-shared electronic musical instrument wherein selected keys are assigned to respective time slots in a repetitive timing interval. During each such interval, a first flip-flop is set by occurrence of the first assigned pedal key. A second flip-flop cooperates with the first flip-flop, and is set during each time interval by occurrence of a second assigned pedal key. A third flip-flop is set at the end of each timing interval to copy the contents of the second flip-flop. The third flip-flop thus provides, during the subsequent timing interval, a signal indicating that two or more pedal keys are being played.

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: Method and apparatus for synthesis or imitation of sounds of musical instents wherein the partial tone structure is a function of the volume or intensity impression to be effected with a listener, and controlled by controlling the relative content of signal contribution in the overall signal of component signals in such a manner that the timbre of the resulting sound will simulate that of softly played (piano) or loudly played (forte) sound; in a system, signal sources representing the signal components are relatively mixed, for example by a control volume control, and applied to an amplifier; or a signal now U.S. Pat. No. 4,064,482, Maisch et al. source generating a composite signal including all components is connected to a plurality of filters and subsequently connected amplifiers of controllable pass frequency and damping (amplification) characteristic to synthesize the timbre of piano, or forte music regardless of actual volume of output.

Abstract: A circuit arrangement for generating the tones of a tonal scale includes a master oscillator and a number of sets of frequency converters. The output signals of each set of frequency converters forms each of the tones of an octave. A frequency shifter is connected between at least one selected set of frequency converters and the master oscillator in order to shift the frequency supplied to the selected set of frequency converters from the master oscillator to cause a desired shift in the frequency of each of the tones of the octave produced by the selected set of frequency converters.

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 delayed vibrato signal generating arrangement in which an envelope signal which changes from a first potential level to a second potential level at the instant of key depression, and thereafter varies gradually from the second potential level to the first potential level is generated by an envelope signal generator, the peak portion of such envelope signal is clipped off by a clipper, and then a vibrato signal with a gradually increasing amplitude is generated by a vibrato signal generator driven by the output of the clipper. The vibrato signal generator is so arranged as not to operate at the clipped level of the output of the clipper, thereby giving a delay time for delayed vibrato.

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: Tone generation in a musical instrument is accomplished by repetitively computing a Fourier algorithm using stored sets of harmonic coefficients. An alterable voice is obtained by optically reading a data card, converting the data to a data format used by the tone generating circuitry, and storing the converted data to be employed as a set of harmonic coefficients. Harmonic coefficient data is encoded on the data card by imprinting columns of opaque areas. The length of each column is measured by sequentially scanning a linear array of light sources. Insertion of the data card in an enclosure automatically initializes the reading circuitry and removing the card causes each opaque data column to be measured in turn and the result converted to a harmonic component.

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: In this electronic musical instrument, two separate tone generators of different type each produce a tone corresponding to an actuated key switch. Advantageously, one of the tone generators is of the Fourier synthesis type. In the other tone generator, a source waveshape having abundant harmonic components is processed by a tone color and volume control system which modifies the frequency spectrum and amplitude of the source waveshape in a time variant manner. The two generated tones are combined to produce the desired musical note.Actuation of each key switch produces, in an assigned time slot, frequency information corresponding to the selected note, and designating the phase angle between successive sample points to be read from a waveshape memory. In the Fourier synthesis type generator, plural waveshape memories store harmonically related sinusoids, all of which are accessed simultaneously and weighted by harmonic coefficients to produce the first tone.

Abstract: Sliding overtone generation is implemented in a computor organ of the type disclosed in U.S. Pat. No. 3,809,786. In such an instrument, the sampled amplitudes of a musical waveshape are computed in real time by individually calculating the amplitude contributions of the Fourier components constituting the waveshape. In accordance with the present invention, one or more of these Fourier components is evaluated at a frequency which varies with time. The resultant overtone "slides" up or down in frequency between preselected limits at a controllable rate of "slide speed". Unusual tonal effects are achieved.

Abstract: In an electronic musical instrument, in particular an electronic organ, comprising a circuit for electrically modifying a musical tone by frequency modulation to provide an ensemble effect. The circuit comprises three series connected shift registers which operate as delay circuits and which are driven by three high-frequency oscillators. The oscillators are driven by three vibrato signals. The vibrato signals are out of phase with each other so that each of the clocks is driven by a differently phased signal. The outputs of the shift registers are filtered and are then recombined either electrically or acoustically or both so that a chorus effect is produced. Additionally, the output of the last shift register in the series combination may be fed back to the input of the first shift register in the series combination to introduce additional phase delay in the audio signal for richer ensemble effects.

Abstract: An electronic musical instrument wherein, by merely depressing one key, the tone pitch corresponding to that key varies periodically with cyclic repetition at a specific rate. The pitch variation is made on the octave basis by periodically shifting digits of binary signals of plural bits which designate readout addresses of a musical tone waveform. Various patterns of the pitch variation can be obtained by suitably setting a pattern of shifting of the digits of the binary signals.

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 pulsato generating system which is composed of a sequentially phase inverting signal generator for producing first, second and third sequentially phase inverting signals based on an input musical signal, a phase rotating signal generator for producing first and second phase rotating signals based on the first, second and third sequentially phase inverting signals and first and second speakers respectively supplied with the first and second phase rotating signals.Another pulsato generating system is disclosed which is composed of the abovesaid sequentially phase inverting signal generator and first, second and third speakers respectively supplied with the first, second and third sequentially phase inverting signals derived from the sequentially phase inverting signal generator.

Abstract: A volume controller for an electric musical instrument of portable type, in which an audio-signal transmission circuit is provided in the signal path of the electric musical instrument. The audio-signal transmission circuit includes a variable circuit element. A pendulum is provided in a casing of the electric musical instrument so as to be swung about a supporting shaft. The value of the variable circuit element is controlled in accordance with the swing of the pendulum to vary the sound volume of the electric musical instrument. A level may be provided on the casing to indicate the controlled condition of the pendulum. A stopper may be provided to tempororily stop the swing of the pendulum.

Abstract: A digitally controllable amplifier unit and musical instrument amplifier incorporating such a unit. Digital control of the transfer function of a high-gain virtual-earth amplifier is effected by switching input and feedback impedances by means of transistor switches. Digital storage means are used to control the transistor switches.

Abstract: An electronic musical instrument of a type wherein a plurality of systems are provided each system comprising memories storing respective harmonic component waveshapes which are read at the same reading rate and the read out harmonic waveshapes are suitably mixed to obtain a desired musical tone. Each system also comprises a circuit for controlling the envelope of the waveshapes read from the memories. In the first system, the envelope control is made in such a manner that the envelope will rise upon depression of a key, thereafter maintain a constant level as long as the key is kept depressed and decay upon release of the depressed key. In the second system, the envelope is controlled so that the envelope will rise in a short time and immediately decay thereafter. The respective harmonic waveshapes thus controlled in envelope in the respective systems are then suitably selected and mixed together.

Abstract: A method and circuitry for frequency generation, especially for electronic organs, in which a digital signal is developed by the actuation of an element such as a key of an organ keyboard. The digital signal is converted to a respective voltage signal and the voltage signal is employed to control a voltage controlled oscillator which supplies a signal corresponding in frequency to the actuation of the aforesaid element. An organ provided with a system for frequency generation according to the present invention can be operated monophonically or polyphonically and is capable of producing desirable effects, including celeste and portamento effects.

Abstract: A signal animation system for an electric organ or other electrical musical instrument which utilizes frequency-proportional detuning wherein the percentage detuning is progressive and uniform, to provide celeste and other musical effects. Detuning is accomplished by a shift register through which sampled electrical representations of an input tone signal are shifted progressively through the register from the input to the output, which delays the signal. The trigger pulses which time the shifting function are frequency-modulated in a manner such that the period of the trigger pulses, rather than their frequency is proportional to a control voltage supplied to the trigger pulse generator.

Abstract: A tone generator for an electronic musical instrument. In the tone generator, a coincidence output is produced when contents of a counter which successively counts a clock pulse have amounted to a value representing a tone of a depressed key. The counter is reset by a reset pulse with delay of a predetermined clock time from the time when the coincidence output is produced.An example is disclosed in which an output of a desired period is statically produced by generating the reset pulse with delay of selected number of clock pulses with respect to the coincidence output. Also disclosed is another example in which desired signals among a plurality of delayed signals produced with delay of one or more clock pulses with respect to the coincidence output are dynamically selected for resetting the counter in response to an output of another counter which cyclically performs counting.

Abstract: This disclosure is concerned with the production of pitch variations, tone alterations and other related effects on keyboard musical instruments and the like effected through mechanisms activated by individual longitudinal finger movement along the longitudinal axis of the keys.

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: A method and apparatus for generating tone signals for a musical instrument, especially an electronic organ, in which a stable high frequency source which is equal in frequency to that of a reference pitch multiplied by a large whole number is divided down by a number differing a predetermined amount from the large whole number, and the thus divided down frequency is supplied to a phase lock loop which, in turn, supplies a synthesizer which will develop a range of pitches over a musical scale. By further dividing down the synthesized pitches, octavely related pitches can be obtained for the supply of pitches in conformity with the number of playing keys in the instrument and the number of ranks of pitches desired. The thus generated pitches differ slightly from the reference pitches by being either somewhat sharp or somewhat flat and when combined with the reference pitches produce desired effects.

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 non-linear type digital-to-analog converter comprising a decoder, control switching circuits controlled respectively by the outputs of the decoder, and an exponential function generating circuit whose analog outputs are selectively produced by the operation of the control switching circuits. An input digital representation is converted to an analog voltage output which is exponentially related to the input.

Abstract: A programmable rhythm apparatus for use with an electronic musical instrument comprising a sequential pulse generator, a plurality of individually programmable rhythm channels or tracks each producing an output pulse pattern in response to the sequential pulse generator and a standard voice generation circuit to receive the pulse output pattern from the programmed rhythm channels. The voice generation circuit produces a signal representative of an unpitched musical instrument with a rhythm pattern corresponding to the pulse output pattern of an individual rhythm channel. The voice generation circuit output signals corresponding to each rhythm channel and representing different unpitched instruments are combined and applied to an audio transducer. Each individual rhythm channel can be programmed by the instrument player to provide a pulse output sequence representative of any rhythm pattern desired. Each rhythm channel has a plurality of logic means and a selection means.

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: A tone generator system for an electronic organ which is capable of being fabricated into an LSI structure and receives a saw-tooth wave or staircase wave as an input thereto comprises a frequency divider for the saw-tooth wave or staircase wave including a ladder resistor network and a complementary MOS FET devices, an analog switch having a wide dynamic range and a high linearity in input-output transfer characteristic constructed by MOS FET devices to serve as an indirect keying means, a sustain means including a novel structure of a variable impedance element which is constructed to control a channel current in a MOS FET device by varying the potential distribution in the source region, and an impedance coverter constructed by complementary MOS FET devices and free from a D.C. level shift. With the above arrangement a tone generator system of high quality for an electronic organ is provided.

Abstract: An automatic arpeggio musical instrument includes a pulse generator having a plurality of keys for generating periodic pulses by depression of one of the keys, each of the keys generating a voltage, a timing pulse generator connected to the pulse generator, a memory connected to the timing pulse generator for generating digital signals of a musical scale, digital-to-analog converter means connected to the memory for converting the digital signals into analog signals, a processor connected to the converter for selectively adding and subtracting the key-generated voltage to the analog signals, and for generating an output voltage therefrom, and a voltage-controlled oscillator connected to the processor for controlling the output voltage.

Abstract: A keyboard instrument having key-operated switches connected in groups corresponding to musical octaves. The groups of keys are pulsed sequentially to provide successive patterns of pulses on parallel time-shared output lines, each group of keys having its own time slot by which the octave of the notes is identified. The pattern of pulses during each time slot identifies the notes within the octave that are to be generated. A repeat signal generator periodically modifies or interrupts the pattern of pulses during the associated time slot. The pattern of pulses may be in effect interrupted as to the keyed note by shifting the pattern of pulses to an adjacent time slot corresponding to another octave for repetitively generating the same note alternately in two octaves.

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: Electronic tone transposition apparatus in an organ allows the front digitals of the keyboard to play different musical scales and to play the diatonic scale in different keys. The apparatus physically actuates a key signature of written music by interchanging the electrical coupling to a front digital with the coupling to its adjacent back digital. The number of such interchanges is equal to the number of flats or sharps in the key signature. The organ can be electronically switched so that the front digitals of the keyboard play different musical scales with different numbers of tones per octave span.

Abstract: An electric organ utilizes digital encoding and time division multiplexing to transfer both function selection and note selection information from manually operable switches to respective memories, and to simultaneously produce tone signals corresponding to stored note selection information. A single encoding circuit encodes in binary form the function and note selection information during successive scanning periods established by a single multiplexing circuit. A plurality of stored note codes are transferred on a time division multiplexing basis to a note selector which selectively produces all of the selected tone signals, on one output in multiplexed form. The tone signals are demultiplexed to generate a corresponding plurality of tone signal outputs. An octave selection circuit which is responsive to a part of each note code selectively reduces the frequency of the demultiplexed tone signals.

Abstract: A circuit is shown for changing the frequency of a basic keyed oscillator by controlling the amount of keying voltage reaching the oscillator and the circuit used for vibrato. The purpose of this circuit is the achievement of true "pipe organ celeste" effect without using an added rank or set of oscillators. Circuits are described wherein the harmonic structure of the signal resulting from this modification of a basic keyed oscillator can be made to change by means of controlling the amount of keying voltage reaching the oscillator for the purpose of achieving the desired harmonic structure of the rank when operated in the "non-celeste" mode as opposed to the "celeste" mode. A circuit is also described for amplitude modulation and harmonic structure modulation at the vibrato rate to enhance the vibrato.

Abstract: A touch sensitive device is associated with at least one key of an electronic musical instrument such as an electronic organ, includes a layer of a pressure responsive, variable conductance material, and exhibits a switching action when subjected to pressure beyond a threshold pressure, any increase in pressure thereafter providing an increase in conductance up to a saturation pressure. The device may be used either as a combined switch and amplitude control or may be used in associated with one or more capacitors to provide either a high pass or low pass touch-control audio filter. In a totally polyphonic instrument a tone generator and touch-control filter are respectively associated with and responsive to each key depression, the output signal from each activated filter being coupled preferably to audio mixer circuitry.

Abstract: This invention relates to a electronic chorus and tremulant system for an electrical musical instrument such as an electronic piano or an electronic organ. A plurality of different sub groups of tone signals representing musical notes are separately collected from a conventional tone generating system. A bucket brigade delay line vibrato system is incorporated in each of a plurality of transmission channels each having a loudspeaker at its output. The instantaneous pitch of the signals in each channel is cyclically varied by varying the time delay introduced by its bucket brigade delay line. The instantaneous pitch in each channel is caused to be different from the instantaneous pitch of every other channel so that a multiple voice chorus effect is produced.