Abstract: An electronic digital timing control apparatus for controlling different durations for two sequential events in alternation, especially in environmental systems. The timing control apparatus is programmable and contains a single oscillator and a binary counter which counts a predetermined fixed number of output cycles from the oscillator. At one end of the first count, tuning components for the oscillator are switched in order to change the oscillator frequency and thereby the duration for the next count for the next corresponding event.

Abstract: The present invention is an electronic piano that includes various "easy play" features that enable a person with little musical training to play the piano producing music similar to that of a skilled musician. The "easy play" feature automatically creates musical and rhythmic piano accompaniment patterns in response to playing either one key (One Finger Chord mode) or a chord (Funchords mode) with the left hand. The player plays the melody of the desired tune with the right hand. Instead of having to move the fingers of the left hand to play complex piano accompaniment patterns, as with a conventional piano, the player only needs to play a note or chord, and move the finger or fingers of the left hand to a different playing key or keys to change chords and patterns. In the standard piano mode, this instrument resembles an acoustic piano in function. The invention also includes a set of pushbutton switches which control the "easy play" features of the instrument.

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 two-phase, period-proportional voltage-controlled oscillator circuit is provided for clocking an analog delay line which can be used, for example, in an electronic musical instrument. The voltage-controlled oscillator circuit provides two clock output signals of opposite phase and having a period directly proportional to the control voltage, i.e., the frequency of the two clock signals is inversely proportional to the control voltage. Since the delay provided by the analog delay line is directly proportional to the period of the clock signals, the delay is directly proportional to the control voltage thereby eliminating a source of distortion in a delay modulation system.

Abstract: The present invention relates to a process and apparatus for use in musical instruments. In particular, the invention is useful for identifying a chord played on a keyboard of a musical instrument, such as the accompaniment manual of an electronic organ, and for identifying the root and the type of chord being played. Pursuant to the invention, a microprocessor used in conjunction with the instrument selectively causes the associated circuitry of the pedal and/or accompaniment keyboard of the musical instrument to play automatically in an appropriate octave either the identified root or a sequence of notes which is compatible with the identified root and chord. A pedal override feature is also provided which overrides the chord identification invention when the musician plays one or more pedal notes.

Abstract: A multiple octave generator system for providing tones in an electronic organ permits the production of both ensemble and celeste effects by providing the appropriate amounts of detuning among cascaded ranks of divide-by-two locked octave type tone generators. The generator system programs from the ranks adjacent octaves of generator into groups having slightly overall stretched tuning which, when combined with an unstretched rank, closely resemble pipe organ celeste tuning. This permits the celeste beat rate of the lower octaves to be increased to a more desirable rate without causing the beat rate of the upper octaves to become too fast.

Abstract: A string chorus generator in an electronic musical instrument that accepts a single audio input signal, applies it to three separate delay lines, and provides delay modulated outputs to be used in producing an ensemble musical effect resembling a group of strings in a string orchestra. Each of the three delay line channels is identical and comprises an analog shift register driven by a high frequency voltage-controlled oscillator along with appropriate filters and buffers. The frequency of the voltage-controlled oscillator of each channel is controlled by the filtered output of a microprocessor, thereby providing precise control over the modulation of each voltage-controlled oscillator. The modulating waveshape is generated by using a lookup table within a microprocessor and comprises a sine wave of 6.25 Hz superimposed on another, larger amplitude, sine wave of 0.78 Hz.

Abstract: Simultaneously played notes on a keyboard are automatically provided with different voice timbres. The assignment of voices to notes is by relative frequency-scale position within the chord. If four or more notes are played, the notes are scanned along the musical scale and the three lowest notes played and the highest note are sounded in different voices with the solo voice assigned to the highest note. Assignment of voices occurs automatically when fewer than four keys are played. Time division multiplex digital logic signals representative of the played keys are applied to a memory circuit and a comparator circuit. If the information stored in the memory from the previous scan cycle is unchanged the comparator provides an enabling signal to a monostable and enable logic circuit. A priority selector circuit provides logic information to the monostable and enable logic circuit which outputs this information and information representative of the total number of keys played.

Abstract: A two-phase, period-proportional voltage-controlled oscillator circuit is provided for clocking an analog delay line which can be used, for example, in an electronic musical instrument. The voltage-controlled oscillator circuit provides two clock output signals of opposite phase and having a period directly proportional to the control voltage, i.e., the frequency of the two clock signals is inversely proportional to the control voltage. Since the delay provided by the analog delay line is directly proportional to the period of the clock signals, the delay is directly proportional to the control voltage thereby eliminating a source of distortion in a delay modulation system.

Abstract: An electronic musical instrument using continuous tone generators capable of simulating the sounds of a conventional acoustical piano. The instrument includes a gating circuit featuring a timed switch travel circuit having a double-time constant for improved control of the dynamic range from the keyboard, and a soft pedal controlling the keying voltage to produce more realistic emulation of the dynamic effects of an acoustical piano. The gating circuit produces a double-time-constant envelope of nearly harmonically related signals for a more realistic piano timbre. The tone spectrum is also controlled as a function of signal level by means of a resistor matrix feeding selected inputs of an active ladder filter, in order to reproduce timbre variation with dynamic level.

Abstract: A multiple-stage active RC distributed filter having multiple inputs and a single output for producing filtering of large groups of notes for tone coloration in electronic musical instruments. Output signals from the keying circuits may be applied to selected input stages of the filter through a resistor matrix to produce the desired tone coloration. Voicing may be further modified by one or more compensation networks at the filter output.

Abstract: Simultaneously played notes on a keyboard are automatically provided with different voice timbres. The assignment of voices to notes is by relative frequency-scale position within the chord. If four or more notes are played, the notes are scanned along the musical scale and the three lowest notes played and the highest note are sounded in different voices with the solo voice assigned to the highest note. Assignment of voices occurs automatically when fewer than four keys are played. One form of the system combines time multiplexed keying with priority coupling of the keying information to a plurality of voltage controlled oscillators through sample-and-hold memory circuits. Each oscillator has its own tone voicing circuits. In another preferred all-digital embodiment, the time division multiplex digital logic signals representative of the played keys are applied instead to a memory circuit and a comparator circuit.

Abstract: An electronic organ in which all the tones of the musical gamut are obtained by operations on the output of a single tone signal source, utilizing digital techniques to divide the frequency of the tone signal by appropriate integers.

Abstract: The present system is a capture action system for electronically recording stop tab configurations in an electric organ, and for recalling the stop tab configurations at will, by depressing of a single control piston for each desired configuration of stop tabs. The system includes provision for setting and recalling combinations of stop tabs associated with a single division of the organ, for example, the swell manual, but not affecting tabs in other divisions, and also includes provision for recording and recalling combinations of all tabs on the organ (general stop) without regard to division. The system further includes a divisional or general cancel function, for operated tab switches, resetting these to inoperative position, and reversible stop functions in which a control piston when actuated reverses the position of its associated stop tab, the reversible stops retaining their abilities to function within the divisional and general combinations.

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.