Abstract: A digital tone mixer includes a first digital volume regulator electrically connected to a first tone generator and having a binary signal output corresponding to the desired amplitude of a pulsating tone signal from the first tone generator; a second digital volume regulator electrically connected to a second tone generator and having a binary signal output corresponding to the desired amplitude of a pulsating tone signal from the second tone generator; a binary adder for summing the binary signal outputs of the first and second volume regulators; and a pulse rate modulator receiving a binary output from the binary adder and generating a pulse train which has a pulse density corresponding to the binary output of the binary adder. The digital tone mixer has a very stable output characteristic.

Abstract: A music synthesizer simulates the musical tones of bowed string and wind instruments. The synthesizer includes a noise generator which generates pulsed noise signals, as well as a resonant system or signal generator which generates deterministic or periodic signals. In one embodiment, the pulsed noise signals are combined with the periodic signals to generate an improved synthesized musical sound. In another embodiment, pulsed noise is added to an excitation signal for energizing a resonating system, which may or may not be dynamically coupled to the excitation generator, resulting in the generation of synthesized sound having appropriate noise characteristics for bowed string and wind instruments.

Abstract: Circuitry for an electronic tone generator effectively isolates a tone modulating RC network from the electroacoustic output device and associated volume control systems. This isolation prevents low or variable impedance of the output portion of the generator from adversely affecting the charge and discharge rate of the RC network. Isolation circuitry includes a MOSFET connected in a source follower circuit to convert the voltage signal from the RC network to a comparable current signal which is amplified through a pair of MOSFETs in a current mirror circuit.

Abstract: A system for automatically generating an accompaniment note pattern and a bass pattern programmed therein by the player. The system includes a programmable microprocessor wherein two patterns, one sounding in the frequency range of the solo and accompaniment manuals and the other in the frequency range of the pedals, can be programmed into a programmable and reprogrammable memory by the player by means of a separate keypad or one or two octaves of keys on the regular keyboards. The patterns are programmed in without regard to key, and on playback, the microprocessor is responsive to the chord being played at that time on the accompaniment manual to transpose the read out patterns to a compatible key. Means are provided for phase locking simultaneously occurring notes of the two patterns if they are of the same or octavely related frequencies. This is accomplished by causing both notes to be taken off the same divider string if a match of pitch occurs.

Abstract: A function selector has an indicating unit which contains several identical groups of switches. All of the switches are connected with a control input of a microcomputer via a common control conductor. Each group of switches is connected to a different data input of the microcomputer by means of an identification conductor common to all switches of the group. An indicating shift register is associated with every group of switches and each switch of a group, as well as its corresponding light source, are connected to a different stage of the respective indicating shift register. An activating shift register is connected in parallel with each indicating shift register. The stages of the activating shift registers are connected with respective function generating elements. The microcomputer has a series of data outputs each of which is connected both with an indicating shift register and the corresponding activating shift register.

Abstract: Disclosed is a frequency-selectable signal generator in which a numeric datum is parallel-transferred to a full adder circuit repeatedly under the control of clock pulse signals, thereby outputting an overflow signal, which is a precise division of accumulation of repeatedly inputting numbers. The frequency of the overflow signal varies with the number represented by the numeric datum. The output signal has a regular pulse-to-pulse interval, and therefore it can be used in producing a musical note.

Abstract: An electronic musical instrument comprises a keyboard device on which a player plays melodies or accompaniments, a sound pitch information or data processing means for producing a sound pitch information or data specified by the operation of the keyboard device and a sound pitch information or data which is above or below the specified sound pitch information or data by a predetermined number of semitones, a sound source responsive to the sound pitch information or data from the sound pitch information or data processing means for generating the corresponding musical sound signals, and an electro-acoustic transducer means for converting the musical sound signals derived from the sound source into the corresponding acoustic signals. The clock frequency of the data processing means can be switched to a lower clock frequency during a data read-out or write-in time interval and a short time interval immediately following it.

Abstract: A tone generator system for an electronic organ, which incorporates N programmable generators (where N is less than 12, and typically 7) which forms a system having the ability to sound notes of N different nomenclature tones at one time. A microprocessor controls the assignment of particular notes to each of the programmable generators, in accordance with the played keys of the keyboard(s) (and the tab switches, in the event that a partial footage is selected). Each of the programmable generators is connected to a chain of dividers and gates which are also under the control of the microprocessor. The information ascertained by the microprocessor from the keyboard(s) (and the tab switches) is used to control the selection of gates which control the passage of tone signals from appropriate dividers in the chains of dividers to an audio output system. More than one note of a particular nomenclature can be simultaneouly gated from the divider chain of a particular programmable generator.

Abstract: A digital semiconductor circuit for an electronic organ has a plurality of control inputs addressed via a keyboard and corresponding in number to the number of keys of the organ keyboard, and a plurality of audiofrequency signal inputs addressed with periodic electrical oscillations by an oscillator system. Each control input is associated with a respective key of the keyboard and each audiofrequency signal input is permanently assigned with a respective tone frequency of the highest octave of the organ. The control signals serve to address the control inputs by the keys of the keyboard corresponding to logical levels "1" and "0." The circuit further includes a number t of divider stages in a frequency divider at least equal to a number q of the octaves in the organ keyboard. A number u of a plurality of AND gates in a given group of AND gates is greater than the number q of the octaves in the organ keyboard.

Abstract: The invention relates to a device for the acoustic indication of the beats of a musical time in which the tempo at which the beats are reproduced is adjustable. According to the invention means are provided for varying the musical properties of the separate beats, e.g. the reproducing period, the volume and the pitch, said varying means being provided with N switch elements each having at least three switch settings, and a scanning element for the cyclic consecutive scanning of the N switch elements, wherein a tone is generated in a first channel during the scan period of each of the switch elements in the second switch setting of the switch element, while a tone is generated in a second channel in the third switch setting of the switch element and no tone is generated in the first switch setting of the switch element in either channel, both channels being common to the N switch elements.

Abstract: An improved system for increasing the loudness of any single note selected by playing more than a single key. A command circuit responsive to manual control, including stop tabs, enables a tone signal to be produced in response to the playing of one key or in response to the simultaneous playing of a plurality of keys on a keyboard. Means are provided for changing the relative amplitude of a tone signal produced in response to the simultaneous playing of a plurality of keys with respect to the amplitude of a tone signal produced in response to the playing of a single key.

Abstract: Each harmonic of the ten provided is represented by a pair of binary-valued signals; one having the form A .sym. B .sym. C, where A, B and C are octavely related square waves, and the other being a square wave like C. Each pair of signals is coupled to a resistive divider by coupling elements in an additive relation under control of an individual adjustable voltage source. The coupling elements are weighted so as to minimize distortion in the signal resulting from the mixture. The resistive divider preemphasizes the signals representing each harmonic to compensate for a voltage controlled filter in the audio output used to eliminate high order distortion components. In one embodiment a .div.3 counter followed by a binary counter provides the binary-valued signals for harmonics of order 0.5.times.2.sup.n, where n is an integer, and a binary counter driven in parallel with the .div.3 counter provides the binary-valued signals for harmonics of order 1.5.times.2.sup.n.

Abstract: A divider keyer circuit arrangement for a synthesis organ utilizing four integrated circuit chips to generate the notes for a 61 key manual with 9 harmonic drawbacks or tabs. On-chip cross wiring and the use of clock lines for synchronization pulses and other design techniques enable the use of four identical integrated circuit chips in standard 40 pin packages to be used to generate the full complement of notes for a 61 note keyboard.

Abstract: An electronic musical instrument having its keyboard divided into plural key ranges with musical tones being generated with tone colors which are different one key range from another. For achieving this object, the instrument comprises channel processors, tone generators, additional tone generators for the lowest (or highest) key in each key range, a common key coder for obtaining key data of depressed keys and a control circuit for supplying key codes delivered out of the key coder to only a channel processor of a corresponding key range. The key coder delivers out key data of depressed keys sequentially one key data at one time slot. According to the invention, the lowest (or highest) tone in a predetermined key range is generated with a tone color corresponding to the key range and also with a different tone color.

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

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

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

Abstract: In a modular, expandable organ system comprising a plurality of large scale integrated circuit (LSI) chips an LSI chip is provided which produces chord and bass frequency generation and identification. It automatically coordinates with another chip in rhythm production. It incorporates frequency generators, identifies a chord played, and provides keyers for chord notes.

Abstract: A brass pulse keyer for electronic instruments such as electronic organs wherein the tone during attack is both amplitude modulated and pulse width modulated. The keyer is adapted for large scale integration and comprises a timing capacitor, an electronic switch connected between a source of charging potential and a capacitor and having a control terminal which is connected to the tone input, and a second electronic switch connected in series with the charge voltage, the first switch, and the capacitor and having a control terminal connected to receive the keying envelope. A comparator compares the potential on the capacitor with a reference potential and disables a gating circuit when a compare condition is reached such that the duty cycle may be controlled. As the keying envelope continues towards its maximum, the duty cycle decreases so that a more brilliant tone is achieved.

Abstract: This invention concerns a monolithical integrated organ gate circuit showing a load resistance common to all audio signal currents. For the suppression of any bounces possibly occurring upon the operation of a second key after a first one, there is a rest current coordinated to each audio signal current which rest current is fed to the load resistance when the related key is not operated and which rest current amounts to the mean value of the related audio signal current.

Abstract: In an electronic organ or the like constructed of a plurality of large scale integrated circuit (LSI) chips, the present disclosure relates to a master control LSI chip having a counter providing multiplexing drive outputs and also having a read only memory (ROM) programmed to provide rhythm voice patterns.

Abstract: An integrated keyer system for use in electronic organs comprising a plurality of discrete integrated circuit chips each corresponding to two adjacent octaves of the keyboard and connected in series to accommodate the entire keyboard. The keyer system is adapted for use in multiplexed systems wherein the keyswitch closure information is encoded in a time division multiplexed data stream fed through a plurality of the keyer chips, which are connected in series. Each of the keyer chips includes a plurality of tone inputs and outputs and a divide-by-four circuit for lowering the tones in by two octaves. The keyer chips also include serial data inputs and outputs and a demultiplexer for demultiplexing the serial data stream at the serial data input to produce a plurality of control signals corresponding to keydown signals in the serial data stream, which are fed to the individual keyers.

Abstract: An electronic organ uses several top octave synthesizer circuits for producing the various tones used in the organ. Each of the top octave synthesizers is capable of producing any tone which can be produced by the organ. As a consequence, the outputs of each synthesizer are applied to a coupler circuit, which in turn is connected to an octave assignment switching tree for directing the tones coupled to the inputs of the switching tree to individual leads, each corresponding to a different octave in the range of tones produced by the organ. The similar octave leads from each of the different octave switching circuits are connected together to common flute octave buses, so that the filters connected to the output buses have substantially fewer tones appearing at the input than one which would have the full tone range of the organ. Typically, the range of tones appearing at a filter input is one octave or less.

Abstract: A tri-state encoding circuit for use with an electronic musical instrument encodes one of three possible states of a device such as a switch, utilizing only a single input line from that device. The tri-state encoding circuit includes, in the case of a single-pole, double-throw switch, a first signal source which feeds signals of like frequency and duty cycle, but 180.degree. out of phase to the respective fixed contacts of the switch. A first gating element is interposed between a source of biasing signal and the movable contact of the switch. Second and third gating elements receive control signals from a further signal source, these control signals being of like frequency and duty cycle but 180.degree. out of phase. These second control signals are also of the same frequency as the first control signals, but may have a different duty cycle.

Abstract: A DC offset correction circuit for use in an electronic organ for eliminating audible noise or thump produced by an instantaneous DC level shift in the standard organ keyer circuit at both key depression and release. A standard keyer circuit is responsive to the depression of a key on the manual by the organist and provides a square or stairstep waveform output at a frequency representative of the note key depressed. Each keyer output waveform includes a positive or negative polarity instantaneous DC level shift at both key depression and release which when coupled through a capacitive output circuit, such as a filter, provides an undesirable audible thump. The DC offset correction circuit comprises a monitoring circuit which is responsive to both key depression and release and a detector circuit responsive to the monitoring circuit to provide a DC level signal output of opposite polarity to the instantaneous DC level shift in the keyer circuit.

Abstract: An organ keyer system, especially a keyer system operated by logic level signals, such as occur in multiplexing.The keyer system herein described is especially intended for manufacture by large scale integration techniques, and is designed to provide for the controlled attack and decay of the keyed signal without the use of timing components, such as resistor and capacitors, external to the integrated circuit.

Abstract: A keying arrangement for electronic organs in which a tone signal consisting of a square wave having, for example, a fifty percent duty cycle is connected to the input of the keyer circuit, and the output thereof, upon the depression of a playing key, consists of a pulse train with the amplitude rising at a controlled rate and the pulse width or duty cycle decreasing at a controlled rate but lagging the increase in amplitude so as to closely duplicate the playing of a muted brass instrument in the attack fashion. A muted brass tremulant affect is achieved by applying a cyclically time variant signal to modulate the pulse amplitude and pulse duty cycle, again with the change in duty cycle lagging the change in amplitude. The circuitry for accomplishing this comprises a diode keyer wherein a pair of resistor-capacitor circuits having different time constants control the keyer to effect variations in pulse amplitude and duty cycle over respective intervals of time.

Abstract: In an electronic musical instrument of the type in which pitch selection is achieved by pulse position modulation, and a rhythm accompaniment is played automatically under the direction of a read-only memory, a shift register is used to create pulse position modulation instructions for harmonic footages of the fundamental note, and selected combinations of these footages are rhythm-modulated and rhythm-counter-modulated under the control of logic gates which are responsive to various manually operated stop tabs.

Abstract: A keying system for an electronic musical instrument in which the absolute value of the amplitude of a musical tone signal generated with a predetermined periodicity is detected so that gating of the musical tone signal is allowed only when the amplitude of the musical tone signal is small, thereby to prevent the occurrence of click noises accompanying the keying of the musical tone signal in correspondence to depression and release of a key in a keyboard.

Abstract: A frequency divider for a tone source for an Arabian scale in an electronic organ of the type wherein musical tone signals for a standard musical scale, musical tone signals higher than the same by 50 cents and musical tone signals lower than the same by 50 cents can be obtained from the output signal of a main oscillator. The output signal of the main oscillator is frequency-divided by at least one frequency divider to obtain an output signal. The aforesaid frequency divider comprises a counter and an AND circuit. An input terminal of the frequency divider is connected through the counter to an input terminal on one side of the AND circuit and is connected directly to an input terminal on the other side of the AND circuit.

Abstract: A keyboard type electronic musical instrument which is provided with a keyboard having an arrangement of keys corresponding to an arrangement of letter names based on the scale of the equal temperament of 12 degrees, a sound signal generator for generating sound signals of frequencies defined for the letter names, first and second gate circuit means having gate circuits respectively supplied with the sound signals from the sound signal generator, a first mixer for mixing the outputs from the gate circuits of the first gate circuit means, a frequency multiplier circuit for frequency multiplying the output from the gate circuits of the second gate circuit means, and a second mixer for mixing the outputs from the frequency multiplier circuit and the first mixer. The sound signals supplied to the gate circuits of the second gate circuit means have higher or lower frequencies than the sound signals supplied to the corresponding gate circuits of the first gate circuit means.

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 a potential distribution in a source region, and an impedance converter 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: A keyer circuit for electronic organs and the like in which a single main keyer chip is formed by utilizing large scale integrated MOS technology with the chip adapted for use with organs having different information supplied to the multiplexing system. The chip provides output information to drive discrete circuitry and also has the necessary input for normal multiplexing operation of an electronic organ. The chip according to the present invention provides internal multiplexing for simple organs and standard external multiplexing for more complex organs.

Abstract: A key assignor comprising a scanning means, a first clock memory, a second memory for releasing a switch information, a comparator, a priority circuit device, a means for inhibiting the write-in operation, and a means for extracting key codes. Key switches are divided into blocks to scan the latter without scanning all of key switches. Scanning time can considerably be reduced as compared to prior arts, thereby enhancing response greatly.

Abstract: A fully digitalized function-of-time generator suitable for use as a tone envelope generator in a digital electronic musical instrument, comprising: a clock pulse generator for generating a clock pulse at a selectable rate; a gate enabled at each arrival of the clock pulse; a single-stage binary shift register for successively shifting out its contents as a digital word representing the instantaneous values of a desired function of time synchronously with the clock pulse; a digital subtractor; a digital multiplier; and a digital adder, all of these members being interconnected to each other to be operative so that the output of the register is subtracted from a first set value representing a digital word, the resulting difference being multiplied by a second set value representing a digital word, the resulting product being added to the output of the register via the gate, so that the resulting sum is loaded into the register.

Abstract: A special circuit arrangement intended for use with electronic organs and the like, and particularly intended for use with electronic organs having playing key operated switches and in which at least a portion of the switches actuated by keys of a keyboard are encoded into binary words during playing.The circuit of the present invention, in particular, is a debouncing circuit which prevents the acceptance by the organ system of a false binary word from the encoder which can be created by the bounce which is inherent in mechanical switches of the type employed for being actuated by the keys of the keyboard.

Abstract: In an electronic musical instrument, a tone source circuit provides tone signals of audio frequencies representing respective notes in a musical scale. A keyboard circuit provides a keying sequence pulses each existing at such a time slot of time sharing at an ultra-audible rate as is assigned to each of keys being depressed. The tone signals and the respectively corresponding keying sequence pulses are AND-gated respectively and then OR-gated commonly to produce a combined tone signal. The keying sequence pulses are obtained by sequentially scanning all the keys in the keyboard in one sequence, or may be equivalently obtained by scanning the same named keys in different octaves simultaneously and AND-gating with octave representing pulses. Or the octave representing pulses may be omitted by separately processing tone signals octave by octave. The system is suitable for digitalization and for production in IC configuration.

Abstract: An electronic musical instrument includes a pitch determining voltage signal generating circuit adapted to produce one of 12 pitch determining voltage signals having different magnitudes corresponding to 12 notes in one octave in response to any of keys belonging to different octave ranges in a keyboard and having the same note name. A pitch determining voltage signal common to the different octave ranges is converted by a voltage converting circuit and taken out as a voltage signal having a magnitude corresponding to the note of a key being depressed on the keyboard. The voltage converting circuit includes a voltage dividing network having a plurality of output points and gate circuits connected to the output points, respectively. Each gate circuit is enabled in response to the depression of a key belonging to a corresponding octave range.

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: A sample hold arrangement for a key signal in an electronic musical instrument in which a keyboard circuit generates a voltage corresponding to a depressed key. The keyboard circuit is connected at its output terminal to an input terminal of a comparator. An output terminal of the comparator is connected to a memory capacitor and a buffer circuit through two gates connected in a series with one another. An output terminal of the buffer circuit is connected, in turn, to a second input terminal of the comparator, and one of the two gates is connected with its control electrode to a detection circuit. A circuit closing signal is generated by the detection circuit when the potentials of the two input terminals of the comparator become substantially equal. The other one of the two gates is connected with its control electrode to an output terminal of a keying signal generator which generates a keying signal of the keyboard circuit.

Abstract: A keyboard operated electronic musical instrument such as an electronic organ is disclosed which generates a musical tone signal by mixing together two different musical tone signals of different waveforms and which changes the sound of the generated musical tone by changing a the amount of mixing of the two signals. A clipping gate with a so-called sustain function is included for controlling the attenuation of an input signal as it passes to an output terminal while clipping the input signal gradually and smoothly so that the musical tone does not disappear instantly but attenuates gradually after the release of a depressed key. The input signal to the clipping gate circuit is a square wave signal, and a square wave signal derived at an output thereof is converted to a waveform other than a square wave.

Abstract: The embodiment of the invention disclosed herein is directed to an electronic musical instrument of the keyboard type wherein the audio frequency signal information is derived from a multi-frequency generator formed by an electronic oscillator and a plurality of divider circuits, and wherein programmable divider circuits are associated with the various keys of the keyboard to generate associated tone signal information. The programmable divider circuits are formed on a large scale integrated circuit chip and enable alteration of the numerical divisor so that different tone signals can be obtained from the same electronic circuitry thereby enabling the same type of LSI chip to be used for many different circuit configurations. The LSI chip also provides a scanning circuit that scans an X-Y matrix switching arrangement to determine which one of a plurality of key switches is closed.

Abstract: The embodiment of the invention disclosed herein is directed to an electronic keyboard musical instrument wherein all the audio frequency signal information is derived from an oscillator multi-frequency generator and frequency divider circuits formed by large scale integrated circuits. The divider circuits associated with various keys of the keyboard generate tone signal information for each of the particular notes of the various octaves. The integrated circuit unit has a plurality of frequency input terminals arranged for connection to the multi-frequency generator and a plurality of second input terminals arranged for connection to its associated key switch on the keyboard of the musical instrument. Actuation of the key switch on the keyboard will enable gate circuits to transfer output signal information from the associated divider into the audio-amplifier stages of the electronic musical instrument.

Abstract: This invention discloses control circuitry for an electronic musical instrument including a keyboard, a voltage divider circuit coupled to the keyboard to provide a pitch determining voltage signal corresponding to a depressed key, a storage capacitor for storing the pitch determining voltage signal, voltage-controlled tone signal generating means responsive to the pitch determining voltage signal and adapted to produce a tone signal corresponding to the depressed key, and control voltage waveform generating means responsive to a trigger signal and adapted to produce a control voltage waveform which is coupled to the voltage-controlled tone signal generating means so as to control the tone signal to be generated thereby.

Abstract: A musical instrument including an electronic organ provided with sound generators of an upper manual, a lower manual, a bass and a rhythm section. The sound generators are connected electrically to control switches in a console, these control switches being actuated by spaced horizontal, arcuately disposed, rows of main, switch actuating, pedals selectively operable by a person's left foot. The main pedals are disposed also in vertical rows corresponding to a basic note of a chord while the horizontal rows correspond to the key of each basic chord. A diode logic, in cooperation with the sound generators and control switches, dictates a prescribed chord of the lower manual sound generator to be sounded when a main pedal is depressed.

Abstract: A fully digitalized function-of-time generator suitable for use as a tone envelope generator in a digital electronic musical instrument, comprising: a clock pulse generator for generating a clock pulse at a selectable rate; a gate enabled at each arrival of the clock pulse; a single-stage binary shift register for successively shifting out its contents as a digital word representing the instantaneous values of a desired function of time synchronously with the clock pulse; a digital subtractor; a digital multiplier; and a digital adder, all of these members being interconnected to each other to be operative so that the output of the register is subtracted from a first set value representing a digital word, the resulting difference being multiplied by a second set value representing a digital word, the resulting product being added to the output of the register via the gate, so that the resulting sum is loaded into the register.