Abstract: In a digital electronic organ or the like external waves of controllable duty cycle are used to control the on time of a field effect transistor (FET) through which a capacitor is charged. A similar rectangular wave of controllable duty cycle is applied to a second FET to control the on time thereof for controlling the discharge of said capacitor. The state of charge of said capacitor is used to control the conductivity of yet another FET through which a desired frequency is conducted to effect enveloping of such frequency with the desired attack and decay characteristics.

Abstract: A soundboard for pianos is provided which is of laminated construction, comprising three plies. The top and bottom plies are of equal thickness and lie in planes parallel to one another. The grains of these plies are also parallel to one another. The center ply is of greater thickness than the sum of the outer plies, but of less thickness than twice the sum of the two outer plies. The grain of the center or core ply is at right angles to the grains of the two outer plies.

Abstract: A plurality of rectangular waves of selected duty cycles and fundamental frequencies are generated. Selected ones of these waveforms are then added at selected amplitude ratios. Such additions provide resultant waveforms of desired fundamental frequencies and having desired harmonic contents or spectra, for simulating the characteristic sounds of acoustical musical instruments.

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: In accordance with the present invention, twelve different partials for a bass rhythm pattern are stored in only four columns of a ROM (Read Only Memory). The first three columns comprise a straight binary encoding of six different partials including the bass root, as well as no bass, while the fourth column is used for determining which of two octaves is to be played.

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 portamento system is disclosed for use with an electronic musical instrument, and particularly with a monotonic keyboard instrument which utilizes master oscillator/divider elements for tone generation. The portamento system utilizes a voltage controlled oscillator, and an oscillator control circuit comprising a unique combination of a phase/frequency detector and a circuit for varying and controlling lock up rate and expanding the frequency range of the system which may be either a ramp and hold circuit or a frequency tachometer circuit. The voltage controlled oscillator is thus locked on to the input frequency from the electronic musical instrument with substantially zero phase and frequency error. The system is capable of reaching the input frequency as slowly or as rapidly as desired and will operate over a wide frequency range.

Abstract: A binary interpolator circuit is embodied in an electronic musical instrument for producing a relatively smooth, inaudible transition between steps of different amplitude in a stepwise advancing or decreasing waveform, such as an envelope signal for a note from a percussive type instrument or voice such as a piano. The binary interpolator circuit includes a counter circuit for producing a sequence of stepwise changing binary coded signals and a combining circuit for combining the interpolating signals, in the sequence produced, with a binary coded scaling signal corresponding to the amplitude difference between the two points in the stepwise changing waveform between which interpolation is desired. A comparator circuit compares the interpolating signals, in the sequence produced, with the scaling signal and produces an output control signal for indicating whether the binary coded numbers corresponding to the respective interpolating and scaling signal are equal.

Abstract: An electronic musical instrument develops digital pulses corresponding to electronic waves that are subsequently converted to audio sound such as by means of a loudspeaker. The musical instrument is provided a source of master frequency generated binary related numbers which act in conjunction with a read only memory, an adder, and a comparator, and also a counter, to control a J/K flip-flop to produce a pulse train output in which for any given cycle the starting time and duration of each pulse is controlled, thereby to determine the harmonic content of the electronic waves that are converted to audio sound.

Abstract: In a modular, expandable organ system comprising a plurality of large scale integrated circuit (LSI) chips an LSI chip is provided which produces frequencies corresponding to notes played on an organ keyboard. Outputs of different duty cycles of rectangular waves are provided for best simulating desired sounds. Other outputs are provided in which the notes are in octave groups facilitating filtering thereof. Each group of outputs has different attack and decay characteristics respectively under the control of the organist so that similar or different types of attack and decay may be provided on different outputs.The present LSI chip provides three generators on one chip. The chips are capable of being interconnected such that any multiple of three generators may be provided.

Abstract: A large scale integrated circuit chip is provided with internal tone generators and digital attack and decay features interconnected with external capacitors for controlling the attack and decay of tones. External diodes are wired to the chip and to the external capacitors and have a circuit completed by a damper switch. According to the position of the switch the capacitors will discharge slowly for long sustain of tones, or will discharge very rapidly through an additional discharge path on the chip upon key release to produce very rapid decay.

Abstract: An automatic chord control system is readily incorporated in an electronic organ by means of large scale integrated circuit chips. The automatic chord control causes a chord or group of notes within an octave played on the lower manual keyboard to play through the upper manual voice in the octave below the lowest melody note being played on the upper manual keyboard. The proposed automatic chord control system has two operating modes. In the first mode, the notes transferred to the upper manual are generated in direct correspondence to the keys activated on the lower manual. In the second mode, the notes transferred to the upper manual are generated by a set of preset chords activated by single lower manual keys.

Abstract: An electronic organ or the like is provided with a plurality of frequency generators greatly less than the number of keys on the organ. Each generator is capable of producing an electrical oscillation of proper frequency for any musical note on the organ keyboard. The frequency generators are assigned to the desired frequency called for by depression of any key. Pulses are dropped, preferably in different numbers, from the frequency generators to avoid locking of oscillators in any musically desirable relationship to one another, including octave or harmonic relation.

Abstract: A programmable rhythm unit is disclosed for electrically simulating sounds of a plurality of rhythm instruments being played in selected ones of a plurality of different rhythmic patterns. A variable frequency oscillator cooperates with a counter/divider and decoder circuit to provide a predetermined number of beats or pulses per measure at a tempo which may be varied by the user. Also provided is a plurality of keyed audio circuits which each produce a characteristic burst of output signals that simulate the audible output or voice of a corresponding rhythm instrument. Switching means are provided whereby the user can select any of the voices to play at any beat position. In addition an alternate beat pulse source is provided which can be selected by the switching means to play any of the voices at a particular beat position every other measure. A pseudo-random generator is also included which may be selected to play any of the voices at a random beat position in each measure.

Abstract: A LSI (large scale integrated circuit) device is disclosed which generates 12 output frequencies related to each other by a multiple of the twelfth root of two from a common time base without the use of parallel divider or shift register strings. The output frequencies comprise the top octave, or a multiple thereof, of the frequencies of an electronic musical instrument. A binary counter serves as a common time base and encodes each wave form period in a form of a binary code. A binary processing circuit associated with each output frequency stores the count position of the next desired wave form transition and updates the stored code after each transition has occurred. The binary processing circuitry comprises a latch circuit, a binary full adder or ROM (read only memory), a digital comparator or ROM, and a J-K flip-flop circuit. The outputs can be easily modified in both actual frequency and waveform symmetry.

Abstract: A non-volatile programmable memory storage system for use with electronic musical instruments is provided which utilizes an erasable and reprogrammable read only memory (EPROM). The EPROM is provided with suitable erasure means, either electrical or ultraviolet light. Also provided is means for entering and retrieving data from the EPROM and means for bidirectionally transferring data between the EPROM and the electronic musical instrument.

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: 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 phonograph selector and memory system which enables the selection of records to be played after the proper amount of credits have been accumulated in a coin accumulating circuit. The system has a movable record carriage for placing a desired one of a plurality of records at a playing location. The record carriage is transported by receiving a drive signal indicating that a new carriage position is required. The code signal information is compared so that when the carriage is at its desired location the search signal is removed. The movable carriage has a position encoder so that binary code signal information corresponding to the various positions of the carriage can be detected and compared to the codes stored in a random access memory circuit.

Abstract: A sostenuto piano action is provided for upright pianos. Each damper is provided at the top rear thereof with a rubber fitting having a catcher flange or tab thereon. A pivoted sostenuto knife similar to that in a grand piano has a blade thereon which, upon pivoting of the sostenuto knife, will catch or engage the catcher tab or flange of each fitting to retain retracted such dampers as are in retracted position. With the knife pivoted to sostenuto position and additional notes played thereafter the flanges will bump the backside of the knife, but will not be caught. Spring biased elbows or hinges are provided in the damper levers to allow "breaking" of the levers at such time so as to avoid providing a strange feel to the pianist. The rubber nature of the fitting prevents any noise at such time.