Abstract: Multiplexed serial data from the keyboard of a musical instrument, such as an electronic organ, is delayed in a shift register to cause generation of musical tones related to the keyswitches closed on the keyboard and combined with the non-delayed serial data for producing mutation voices or chords.

Abstract: Electronic circuits are provided for producing an electronic timbre modulation for effecting celeste or vibrato similar in sonic results to the well-known Leslie rotating speaker system. Electronic signals corresponding to audio tones are generated and are modified by appropriate filters. Three controlling oscillators are locked in exactly 120.degree. phase relation to one another and act through three voltage controlled oscillators respectively to modulate three bucket brigade circuits through which said modified electronic signals are passed substantially in parallel. A roving band pass filter further modulates those of said electronic signals corresponding to flute tones to simulate other aspects of a Leslie speaker system.

Abstract: A non-volatile memory system for an electronic musical instrument having a plurality of player actuatable instrument controls, comprises a readable, writable memory. The memory includes addressing inputs and data input/outputs. The data input/outputs are coupled with at least selected ones of the plurality of player actuatable instrument controls. Player actuatable memory controls are also provided for selecting either the memory or the selected ones of the player actuatable instrument controls for control of the instrument.

Abstract: A detuning control circuit is provided for producing a pitch variation effect in an electronic musical instrument. The instrument includes at least one integrated circuit tone generator chip having at least one tone generator and a detuning circuit responsive to a predetermined detuning control signal for detuning the signals produced by the tone generator. The detuning control circuit comprises a detuning control signalling circuit for producing a predetermined detuning control signal and for selectively applying the predetermined detuning control signal to the detuning circuit of the tone generator chip so as to produce a predetermined pitch variation effect.

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 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 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 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 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.