Kimball International, Inc.

Ralph N Dietrich

John W Robinson

Stephen L Howell

Billy J Whittington

James Patrick Osburn

An envelope generator for use in an electronic musical instrument, such as an electronic organ, employing a dual charge pump to form the attack and decay portions of the envelope. The envelope generator is adapted to be connected to the envelope control input of the keyer and the other input of the keyer is connected to a tone source. When the appropriate key of the keyboard is depressed, a source of input voltage is connected to the input of the envelope generator and a first charge pump incrementally transfers the input voltage to a capacitor over a first sequence of discrete time frames. The first charge pump circuit comprises a pair of electronic switches clocked 180.degree. out of phase and a capacitor connected between the juncture of the two switches and ground potential. The second mentioned capacitor is much larger than the first mentioned capacitor so that the charge transfer from one to the other takes place in a plurality of discrete steps. A second charge pump connected serially between the first charge pump and the envelope input of the keyer incrementally transfers the voltage on the first mentioned capacitor to another capacitor over a second sequence of discrete time frames. The second charge pump also comprises a pair of electronic switches having a capacitor connected between their juncture and ground potential, and a clock which clocks the electronic switches 180.degree. out of phase at a second frequency higher than the frequency at which the first two electronic switches are clocked. This arrangement has the effect of reducing the magnitude of the discrete steps thereby avoiding the audible distortion associated with prior envelope generators of this type. If desired, the second charge pump can be dual phase so that the effective frequency ratio between the second and first charge pumps is effectively doubled.

Envelope generator employing dual charge pump

An electronic rhythm generator which comprises a large read only memory having a plurality of rhythm patterns and rhythm break patterns programmed therein, player operated selector switches for selecting a rhythm pattern and a break pattern, scanning circuitry for sequentially addressing the memory to read out the stored rhythm pattern, and, when the break circuitry is activated, reading out the break pattern in place of or in addition to the rhythm pattern. The rhythm generator is contained on a single monolithic integrated circuit chip with the pattern selection being accomplished by an external multiplexer driven by an internally generated scan word. The break activation circuitry automatically corrects for improper matching of a rhythmically incompatible rhythm pattern and break pattern by either ignoring the break command or substituting a compatible break pattern in place of the selected break pattern. Channel inhibit circuitry at the input and output of the memory permits selective playing of certain ones of the instrument channels during a rhythm break regardless of whether the break is generated internally of the chip or externally by means of a separate break generator.

Electronic rhythm generator

An electronic music synthesizer capable of simulating a wide variety of musical effects, wherein the settings which create the various effects are hard wired on a plurality of selectable circuit boards so that programming of the instrument can be accomplished by the player with minimum effort. The synthesizer encodes a plurality of keys on the keyboard and selects a tone from the tone generator corresponding to the depressed key. This tone is fed through a chain of dividers to create the needed footages, which are then fed to voicing cards that create the different tone sources for the synthesizer. These tone sources are fed into a state variable active filter which modifies the timbre of the tone sources in order to achieve the desired frequency-related effects. The output of the filter is fed to a gain module wherein the amplitude envelope has a controlled attach and decay as well as several different modes of operation such as steady state and percussive, which are selected by means of multiple bit binary words produced at the preprogrammed circuit board. The operating frequency of the filter is controlled by an envelope generator preset in a percussive mode to have a predetermined envelope. All controls for the synthesizer are preset from the voice boards, which are individually connected in the circuit either by tab switch operation or by physically inserting the voice board in a player accessible connector.

Electronic music synthesizer

A circuit for an electronic organ for producing rhythmic patterns of notes in accordance with the selection of a chord in the accompaniment manual. The organ includes an accompaniment manual and a solo manual, either or both of which may be electronically scanned to develop a multiplexed data stream, and a chord generation circuit controlled by the accompaniment manual for sounding groups of notes in the accompaniment voices in response to the depression of one of the selected group of keys on the accompaniment manual. The circuit according to the present invention automatically sounds notes of the solo manual in a rhythmic pattern in response to the depression of one of the group of accompaniment manual keys by developing a logic pulse at the beginning of the top octave scan which is delayed in time to correspond to the time slot of the chord root note and subsequent notes of the chord. The amount of delay is controlled by pre-programmed patterns preselected by the musician.

Method and apparatus for rhythmic note pattern generation in electronic

An electronic rhythm generator particularly suited for incorporation in an electronic organ. A counter, clocked by time sequential rhythm clock pulses, produces a cyclically repeating series of counts comprising binary words having a most significant bit and a plurality of least significant bits which address a read only memory having a plurality of preprogrammed rhythm patterns stored therein. The memory comprises two sections in which a first set and a second set of rhythm patterns respectively are stored and which is programmed such that one of the sections is enabled only when the most significant bit of the counter output is a logic 1 and the other section is enabled only when the most significant bit is a logic 0. The memory responds to a series of sequential enabling signals on certain of its address lines corresponding to the respective least significant bits of the binary words to produce at its output rhythm signals in the rhythm patterns selected within its enabled section. Player actuated override control means are provided for selectively holding the most significant bit of the counter output at either of the aforementioned logic levels so as to cause one or the other of the selected rhythms to repeat for each cycle of the least significant bit portion of the binary word. If the most significant bit of the count is permitted to change states every half cycle of the total count sequence, the rhythm pattern will alternate between the two selected rhythms.

Rhythm generator for electronic organ

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.

Keyer circuit for electronic organ

An electronic organ in which rhythmic note patterns can be played on the accompaniment manual by the depression of a single key. The organ includes a source of rhythmic pulses which may, for example, be taken from the pulse source of a conventional rhythm unit. The accompaniment manual of the organ can be played in a conventional manner or it can be adjusted to play rhythmic note patterns during which the normal playing of the accompaniment manual is disabled and only a selected group of accompaniment keys, preferably a group of adjacent keys at the left end of the keyboard, are enabled for controlling the pattern to be played. When the organ is adjusted for pattern playing, each of the aforementioned group of keys is operable, when depressed, to initiate the playing of a pattern in conformity with stored memories and in further conformity with the respective one of the pattern controlling keys which is depressed.

Method and apparatus for automatically producing in an electronic organ

A variable filter circuit, especially for synthesizing and shaping tone signals, in which a variable light source is provided which influences light sensitive resistor elements in the filter circuit. The variable circuit, by the use of selector switches, can provide different musical features, such as muted voices, percussion, brass, woodwind and the like, all of which will enhance, for example, existing organ voicing while it is, furthermore, possible to obtain the effect of playing a solo instrument together with organ voicing.

Variable filter circuit, especially for synthesizing and shaping tone

An electronic rhythm 'break' pattern generator for use with a rhythm generator of the type used with electronic organs. The break pattern generator, when operative, interrupts the flow of the normal rhythm pattern and substitutes a special rhythm pattern for one cycle of the normal rhythm pattern. The typical pattern is of a type usually played by experienced musicians at the beginning, or end, of a musical composition and form 'lead-in' and 'lead-out' rhythm pattern portions. The system according to the present invention can also provide for an alternate rhythm pattern at any time not limited to the beginning or end of a composition.

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Jasper, IN, United States of America

Ralph N Dietrich