Abstract: An electronic musical instrument having combined monophonic and polyphonic sound producing capabilities includes a keyboard simultaneously operating a monophonic tone signal generating circuit and a polyphonic tone signal generating circuit. The tone signals produced by the tone generating circuits are combined and coupled through a single signal processing stage and therefrom to an output speaker. A gate signal for enabling the monophonic tone signal generating circuit and for operating the signal processing stage is derived at the output of a detector circuit which is responsive to the presence of an audio output from the polyphonic tone signal generating circuit.

Abstract: A manually operated pressure sensitive button assembly is arranged by the side of the keyboard on the top front panel of the instrument, each button being electrically and operationally coupled to an associated element in the main processing system of musical tone signals, in order to control musical tone components such as tone pitch, tone color, tone volume and modulation effect quite concurrently with minimal interruption of the manual operation on the keyboard.

Abstract: An electronic musical instrument having tone signal sources and keyers for the tone signal sources has a time division multiplexer for multiplexing the key-down information in groups such as for the upper manual, lower manual and pedals. The keyers are provided in divider keyer packages with drawbar, or harmonic content, information being synchronously multiplexed with the key-down information to a single set of keyers.

Abstract: An electronic musical keyboard instrument has a unit separate from the main console and having switching means for performing the function of at least some of the keys and stops of the console that unit being adapted to be operated by a handicapped person.

Abstract: An electronic musical instrument is provided with an upper, a lower and a pedal keyboards and musical tone generating circuits dependently corresponding to respective keyboards and, in addition thereto, an auxiliary musical tone generating circuit which is independent of the keyboards and can be selectively coupled with a particular keyboard according to the designation by a keyboard selection switch. This auxiliary musical tone generating circuit produces tone signals having a particular tone color. Key codes for a selected one of the keyboards among key codes supplied by a channel assignment circuit are latched separately in the auxiliary circuit, and musical tones corresponding to the latched key codes are produced in this particular tone color.

Abstract: 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.

Abstract: A data encoder for use with a time multiplexed electronic organ or the like comprises a multiple stage shift register, means for simultaneously loading a predetermined pattern of logic bits in the shift register in response to a key down representative data pulse and means for coupling the output of the shift register to one of the data channels of the organ. In a first mode, the data encoder is operable as a fill-note generator wherein the shift register is loaded in response to an upper manual key down representative data pulse and lower manual key down representative data pulses are coupled to the upper manual data channel of the organ according to the output of the shift register. In a second mode, the data encoder is operable as a chimes generator wherein the shift register is loaded in response to an upper manual key down representative data pulse and the output of the shift register is coupled to the upper manual data channel of the organ.

Abstract: An electronic digital type organ having one or more keyboards generating two or more harmonically related tones in response to keying a melody monophonically on one of the keyboards. The harmonic tones may be of different tonal quality, so as to produce the effect of different instruments. The harmonic tones are generated automatically at a pitch determined by either the next lowest note to the accompaniment notes played on another keyboard or, if no other key is depressed, a pitch that is determined by the melody note and stored half-tone interval information.

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: A keyboard electronic musical instrument comprises a note information processing device capable of processing note information required for automatic arpeggio and automatic bass performances. This note information processing device includes a generation circuit for generating a plurality of note information representing a plurality of notes to be sounded in relation to the key depression, a selection circuit for sequentially selecting a note information designating a note to be sounded from among the plurality of note information from the generation circuit in accordance with a predetermined priority order; an output circuit for delivering out the note information selected by the selection circuit, the selection at each sequence being conducted dependent on the selection at the preceding sequence.

Abstract: A key input apparatus is provided with a plurality of input operation keys and a time signal generating circuit which in correspondence to the number of these input keys performs a step operation to generate in turn a different timing signal. Input signals produced by actuation of the input operation keys pass through a group of first AND gates in synchronism with the corresponding timing signals generated from the timing signal generating circuit. A shift register having bits corresponding in number to the gates of the group of first AND gates receives the output signal of the AND gates via an OR gate. The output signal from the OR gate is applied to one input terminal of a second AND gate of which the other input terminal is coupled with the last bit position of the shift register through an inverter. The outputting operation of the second AND gate is controlled by the shift register and inverter.

Abstract: A method and apparatus for memorizing and playing back an accompaniment passage in an electronic organ wherein the keyboard is multiplexed to develop a serial input data stream having keydown signals in the time slots corresponding to the depressed keys, selectively writing into a programmable random access memory data corresponding to the absolute address of the first occurring keydown signal in the pulse train and then writing into the memory data corresponding to the intervals, expressed in terms of time slots in the multiplexed data stream, between a number of the first occurring keydown signals, beginning with the first occurring signal. The data is read out of the memory and converted to a serial time division multiplexed data stream by means of comparators which produce a pulse each time there is a compare condition between the output of the memory and the count produced by the master counter/subcounter.

Abstract: At least one movable device is mechanically coupled to a coupling device which moves in response to the motion of the movable device. The coupling device moves in a path which closely parallels the path of a time-varying, propagating electric field. Upon interception of the electric field with the coupling device, a signal is transferred through the coupling device by capacitive coupling with the field to an input of a detector. The signal is detected by circuitry which generates a pulse width modulated (PWM) signal corresponding to the period of time between the initiation of the propagation of the electric field and the moment of interception. Circuitry is provided to generate pulse code modulated (PCM) signals responsive to the position location of up to 2.sup.n movable devices.

Abstract: An electronic organ employing the technique of multiplexing at least the solo portion of the keyboard and which includes an automatic chord playing circuit which plays chords in the solo voices corresponding to the accompaniment portion of the keyboard in response to depression of one of a predetermined group of keys of the accompaniment portion of the keyboard. The organ includes circuitry for automatically sounding notes corresponding to the chord selected in the accompaniment portion singly and sequentially from a selected end of the solo portion of the keyboard to the opposite end thereof, and further selectable to begin at one end of the solo manual proceeding to the other end thereof and sounding in reverse order back to the first mentioned end of the manual. If desired, the arpeggio run may be terminated at a selected point on the keyboard short of either end thereof.

Abstract: An electronic musical instrument comprises an automatic rhythm performance device, an automatic bass chord performance device and an automatic arpeggio performance device. Each device has its own start-stop control circuit and a control in/out terminal. When a device is start-stop controlled, a control signal appears at the control in/out terminal, whereas if a control signal is externally applied to the control in/out terminal, the device is start-stop controlled. The control in/out terminals of the respective devices are connected together by a common line so that a start-stop of one device causes the start-stop of other devices.

Abstract: An electrical musical instrument having a digital circuit which automatically generates selected chordally related tone signals in response to manual selection of a root note. A root encoder provides a binary code representative of the root note in response to note selections, and an interval code generator automatically provides code signals having binary number values equal to the number of half steps from the root for a given interval. An adder arithmetically adds the root code and the interval code to generate a code for a chordally related note having both octave and note information corresponding to the automatically generated tone signal. In one mode of operation, the root code represents the root of the root-fifth pair of highest priority around the circle of fifths selected on a manual keyboard. In another mode, the root code is representative of a note selected on the pedal clavier.

Abstract: An electronic musical instrument comprises an upper keyboard channel, a lower keyboard channel and a pedal keyboard channel. The lower keyboard channel includes a tone gate which is actuated by a chord rhythm pattern pulse generated by an automatic rhythm generator to gate the lower keyboard tones. The pedal keyboard channel includes a root/subordinate tone generator which provide a root tone designated by the depressed pedal key and subordinate tones related to the root tone with predetermined musical intervals, and a tone keyer which is actuated by a bass rhythm pattern pulse generated by the automatic rhythm generator to gate the bass tones.

Abstract: An information transmission system for N information signals for the transmission of either N parallel signals, or of only one information signal from a signal range of M signals with M.ltoreq.N at the upper or lower range boundary. N signal transmission gates are provided which can selectively be switched effective, these gates being connected through by means of control signals either for N information signals or for the signals at the upper or lower boundary of a signal range.

Abstract: In an electronic musical instrument, the keys of a keyboard are divided into a plurality of groups by octaves, and a wave generator is provided with a memory for storing constants corresponding to musical tone frequencies to be generated according to the notes includes in a desired group out of the plurality of group, an accumulator for repeatedly adding the constants read out of the memory, and a bit position shifting circuit for shifting the bit position of the data produced by the accumulator according to the octave range of a note to be produced, thereby to obtain the data varying repeatedly according to the frequency of a note to be produced, and to reduce the storing capacity of the memory when compared to the number of keys.

Abstract: A multichannel recording medium storer which samples the time course of notes produced by an instrument and an address for each of these samples. An interchangeable keyboard transmits a signal or signals to an electronic computer as to which note or notes are to be reproduced. The electric computer reads the note or notes to be reproduced from the recording medium and from the sample produces a faithful reproduction of the sustained note or notes. The result is available for recording on one channel of the recording medium or for reproduction on a speaker. The instrument is useful for the preparation of musical compositions and for educational purposes and demonstrations.

Abstract: A sequence generator for a polyphonic tone synthesizer in which a repetitive sequence of musical notes or chords are generated automatically. During a Code mode of operation, each key operated on the keyboard causes an associated data word identifying the specific key by keyboard, octave and note to be stored in a memory. Time data as to the relative time the note is to go on and go off is also stored as part of the data word. During a Play mode of operation, the data words are read out of memory in the sequence in which they were generated. The words are decoded and the time data compared with a real time clock to provide signals to the output of the keyboard which duplicate the signals from the corresponding keys. The time duration of these signals is controlled by the time on and time off data to duplicate the required time that the respective notes are to be played.

Abstract: A stop tablet control system for an organ in which the "on" condition of selected stops is indicated by an illuminated light-emitting diode (L.E.D.) mounted in each stop tablet. The stop tablets are pivotally supported on a tablet rail and spring-biased to assume a neutral position from which they can be momentarily moved up or down against the action of the spring. When a tablet is momentarily pushed down from the neutral position a switch is closed to actuate circuitry which turns on the associated stop and energizes the L.E.D., and when the tablet is momentarily pushed up from the neutral position the associated stop is turned "off" and the L.E.D. extinguished. The system includes control circuitry for providing in a combination stop action mode an indication of what stops are playing.

Abstract: The inventive circuitry extends the harmonic content of musical tones produced by a computor organ of the type disclosed in U.S. Pat. No. 3,809,786. A memory stores values of an algebraic approximation of the summation of the amplitudes of a set of Fourier components of order higher than those separately evaluated by the computor organ itself. As each musical waveshape sample point amplitude is computed by the computor organ, the stored summation approximation value for the corresponding sample point is accessed from the memory. This accessed value is appropriately scaled, and is added to the sum of the lower order Fourier component contributions that are calculated by the computor organ. The resultant sample point amplitudes are converted to musical tones in real time. In an illustrative embodiment, musical tones having the spectral content of a sawtooth wave are produced.

Abstract: A manually played electrical musical instrument of the electronic type in which simultaneously with selection and playing of a melody tone (note) a predetermined pattern of harmonies are also selected in such manner that at least five of the harmonies selected for the appertaining tone are mutually different. The instrument also includes generation of rhythm sound effects which permits programming of predetermined rhythm patterns defining the times of occurrence of predetermined rhythm sounds in a sequence of a predetermined number of beats, and generation of different bass tones according to a sequence of notes.

Abstract: An electronic organ having at least a portion of the keyboard connected with the corresponding keyers by a multiplexing system consisting of a multiplexer at the keyboard end of the system. A control circuit is interposed between the multiplexer and the demultiplexer and is selectively operable for interrupting the change of data in the demultiplexer and, instead, holding therein the data present in the demultiplexer at the time of actuation of the control circuit. The control circuit is adapted to be made ineffective at the will of the player, or by depressing a key in the aforesaid portion of the keyboard. The arrangement permits a player to hold the keyers pertaining to a group of keys from the portion of the keyboard without holding the keys depressed thereby permitting the player to use both hands elsewhere on the keyboard.

Abstract: Electronic sensing and measuring equipment for accurately measuring the pitch of musical sounds and which includes an audio tuner responsive to the fundamental frequency of a continuing signal while rejecting all other harmonically related components of said signal to produce a digital signal representing the fundamental pitch of said musical sound, and a counter for counting and totalizing said digital signal defining the same in terms of its frequency and for visually displaying said defined signal.

Abstract: In order to simplify the intricate wiring in known automatic bass chord systems and to reduce the number of separate decoders used therein for all chords of each key, an apparatus is provided which allows the use of only one decoder per chord type. When a chord is held one bit is applied to the inputs of a first 12-bit shaft register which correspond to the tones of the chord, after which all bits are shifted further by an HF clock pulse until this chord pattern has arrived at those outputs of the 12-bit shift register which, with the inputs of the decoder which corresponds to the chord being held, are assigned to a single pre-selected tonality.

Abstract: An electronic musical instrument capable of producing an attack repeat effect. The attack repeat effect is a musical effect produced by repeated occurrences of attack and decay during a single continued sounding of a musical tone, giving to an audience an impression as if the tone started and stopped repeatedly. According to the invention, a complete envelope shape starting by an attack portion and ending by a decay portion is stored in a memory. When a key on the keyboard is depressed, the stored envelope shape is read from the memory and, upon completion of reading of one cycle of the envelope shape, reading of the envelope shape is resumed from the beginning. A time division multiplexed reading out of the envelope shape is conducted with respect to a plurality of channels. The read out envelope shape is used for controlling the amplitude of the musical tone signal. If the key is released, reading of the envelope shape is no longer repeated for a next and subsequent cycles.

Abstract: A rhythm selection switch arrangement mounted on the operation panel of an electronic musical instrument. The switch arrangement comprises a plurality of on-off push changeover switches arranged successively and a changeover push switch disposed adjacent to the two-position push switch nearest to the player of the electronic musical instrument. The two-position push switches are to select a rhythm, and the push switch is to control the standard or variation mode of the selected rhythm.

Abstract: Circuitry in an electronic organ for electronically storing a series of signals corresponding to depressed keys depression and for recalling the stored series in response to player commands.The circuit allows the player to play accompaniment chords of a piece of music alone and at any desired pace, and then while manually rendering the righthand, or solo, portion of the music. The chords are played by simply depressing a single control button whenever the next chord in the stored series is required.A further feature of the invention is the ability to store sets of switch or tab or other selector element settings for later recall. The selector element setting storage circuit enables the player to switch tab settings during storage of chords, while storing the patterns in the order in which they will be desired.

Abstract: An electronic musical instrument has a plurality of tone selectors which select musical tones; a waveshape calculator which calculates a waveshape represented by amplitudes at two or more than two sampled points of one period of the selected tone and which is operative whenever the tone selectors are actuated; a plurality of waveshape memories which temporarily memorize the calculated waveshapes; clock signal generator which generates clock signals with high frequencies corresponding to pitches of depressed keyswitches of the musical instrument and which is operative whenever the keyswitches are depressed; a reading circuit which repetitively and successively reads out the memorized waveshape amplitudes by the clock signal generated by the clock signal generator; and a converter which converts the waveshape amplitudes read out by the reading circuit to a musical tone, wherein a musical tone is generated by repetitively reading out the temporarily memorized musical waveshape.

Abstract: In a keyboard electronic musical instrument such as an electronic organ, an electro-mechanical memory device for holding in the down or actuated position one or more simultaneously depressed accompaniment chord and bass playing keys after the finger pressure from the instrument player is removed. The signal representing the note or chord associated with the depressed key or keys is sustained as long as the keys remain latched down. A plurality of keys of the lower or accompaniment manual are adapted to be retained in the depressed position and operate as part of the electro-mechanical memory device. When a key or group of keys are latched down, the depression by the instrument player of another key releases the previously retained keys but the newly depressed key is latched down. The electro-mechanical memory also operates in conjunction with the touch mode of the automatic rhythm unit to provide a rhythm signal when the accompaniment keys are retained in the depressed position.

Abstract: A signal generating system for an electronic musical instrument utilizing an electronic beam tube with a radiation intercepting structure and means to derive a signal from beam current pulses produced by scanning the structure. The width of pulses is modulated according to the width of individual components of the structure and the pulse width modulated wave is transformed to analog form by a low pass filter. The structure includes several aligned sections and the widths of each section at corresponding points of alignment are representative of the pulse-sampled amplitudes of the tonal qualities of different musical instruments.

Abstract: A pedal tone generator for an electronic musical instrument, such as an electronic organ, having the capability of automatically producing bass rhythm patterns based on a tonic note, includes a memory for storing a plurality of rhythm patterns which has a plurality of outputs for producing a predetermined pattern sequence for each of the notes of the diatonic musical scale, and a circuit for producing signals indicative of which of the pedal keys, usually thirteen, is operated by the instrumentalist. The pedal key signals are binary encoded to produce a plurality of code words each unique to the tone of one of the keys, and each of the outputs from the memory is also binary encoded to be uniquely represented by one of a corresponding number of code words. Code words representing a depressed key and the note instantaneouly being "played" by the memory are added to produce a coded digital signal representative of the sum in the duodecimal system of counting.

Abstract: The hand-held instrument is preferably supported by a strap from the neck for one or two handed playing of a keyboard with switch and potentiometer controls of a remote synthesizer which may be basically of conventional design and include a plurality of output voice means. A lightweight keyboard assembly is mounted within an elongated premolded housing having a control panel comprised of control switches and light indicators. The instrument is preferably for playing by the right hand, and for the purpose of holding and controlling the stability of the instrument, the housing is formed with a left hand gripping hole or slot permitting the instrument to be firmly gripped. Adjacent the hole there are provided additional control knobs and push button switches which are easily operated by the left hand without any repositioning of the hand. An umbilical cord interconnects the hand supported keyboard musical instrument and the synthesizer apparatus.

Abstract: A console for use in playing an electronic musical instrument. Two manuals are slidably arranged on a stationary frame or desk, to slide sideways toward and away from each other. Each manual carries various keys and other movable control elements to be operated by one arm-hand-finger of the player. On each manual, keys for individual tones are arranged in rows extending front to back, toward and away from the player, rather than in rows extending from side to side as in a conventional piano keyboard. Each key is wide enough so that two fingers of the player may rest simultaneously on the key. In addition to these rows of keys, each manual has other special keys or movable elements, some arranged for operation by the little finger, some for operation by the thumb, some for operation by raising or lowering the hand, for changing the nature, quality, duration, octave, or other characteristics of the sound produced.

Abstract: For reiteration of percussive sounds in an electronic organ there is provided a circuit for generating pulse signals for reiteration control which are "on" for much longer periods than they are "off", thereby substantially reducing the chance of an organ key being actuated when the control signal is in its "off" condition. The circuit is so arranged that playing of an additional key at a time when one or more other keys are being held has no effect on the reiteration of the sound produced by the held keys. The circuit generates four control signals which are connected such that each controls three notes in a given octave on the keyboard, a different three in successive octaves, such that when normal intervals (e.g., thirds, fourths and fifths) are played, the effect of random reiteration control is produced.

Abstract: An electronic musical instrument is of a type wherein musical tone waveforms are stored in a memory as their sampled amplitudes and sequentially and repetitively read out to constitute tone waveforms. A key depression brings forth key code in a digital representation. This key code is used for reading out frequency information from a frequency information memory. The frequency informaton is accumulated to make an address signal for reading out the waveform memory. The read out waveform is reproduced as a musical tone through a tone-color and volume control circuit. This tone-color and volume control circuit is controlled keyboard by keyboard.The key code produced upon depression of the key contains a signal representing the kind of the keyboard to which the depressed key belongs. This signal is applied to a conversion circuit and converted to a signal representative of a different kind of keyboard.

Abstract: An organ circuitry for providing fill notes and a method of operating the organ in which a circuit is provided which adds fill notes automatically in the multiplexed solo manual of an electronic organ, by detecting the first pulse encountered by the multiplexer during a scan of the keyboard and developing further pulses in conformity therewith but pertaining to notes within the octave beneath the note corresponding to the detected pulse, and combining the pulses on a data stream which is demultiplexed for actuating keyers.

Abstract: Electronic musical tone generating methods and apparatus such as electronic organs and music synthesizers are described. An impulse response characteristic of the tones is represented by digital signals which are stored at different locations in a digital memory device. The memory is read out repetitiously at selected rates to produce tones of selected frequency or pitch (different notes of the musical scale). The interval during which the stored impulse response is read out is varied in order to generate the tones with different timbre such that different musical instruments (the stops in the electronic organ application) may be emulated.

Abstract: An arpeggio circuit for an electronic organ employing digital encoding, decoding and code conversion techniques to semiautomatically generate an arpeggio effect composed of tone signals having an octaval relationship and corresponding to selected note keys held down on an accompaniment keyboard. The rate of generation and order of the arpeggio tone signals is controlled by means of a plurality of manually actuatable arpeggio control switches. A plurality of individually identifiable control signals are sequentially generated in response to sequential actuation of the plurality of control switches. The control signals are binarily encoded. Tone signals provided by a set of tone generators are selectively associated with appropriate ones of the encoded control signals by a tone selector circuit which provides the selected one of the tone signals to an arpeggio output tone signal generating circuit when the associated encoded control signal is being generated.

Abstract: An automatic chord generating circuit for a digital polyphonic tone synthesizer having one or more keyboards. Key operated switches are connected in groups corresponding to the notes in an octave. A signal source is selectively connected by the closed switches of each group in sequence to associated ones of a plurality of signal lines. A priority circuit selectively connects a signal from only one line at a time to a corresponding one of a plurality of output lines, so that operation of more than one key in an octave produces only one output signal at a time. A switching logic circuit, responsive to digitally coded input signals identifying any one of a plurality of different chords, connects the single output signal from the priority circuit to additional ones of the output lines for activating multiple notes within the octave.

Abstract: Tone generation in a musical instrument is accomplished by repetitively computing a Fourier algorithm using stored sets of harmonic coefficients. An alterable voice is obtained by optically reading a data card, converting the data to a data format used by the tone generating circuitry, and storing the converted data to be employed as a set of harmonic coefficients. Harmonic coefficient data is encoded on the data card by imprinting columns of opaque areas. The length of each column is measured by sequentially scanning a linear array of light sources. Insertion of the data card in an enclosure automatically initializes the reading circuitry and removing the card causes each opaque data column to be measured in turn and the result converted to a harmonic component.

Abstract: An electronic musical instrument wherein, by merely depressing one key, the tone pitch corresponding to that key varies periodically with cyclic repetition at a specific rate. The pitch variation is made on the octave basis by periodically shifting digits of binary signals of plural bits which designate readout addresses of a musical tone waveform. Various patterns of the pitch variation can be obtained by suitably setting a pattern of shifting of the digits of the binary signals.

Abstract: A single amplitude curve generator is time shared amongst a plurality of musical tone generators for controlling their musical shapes. The curve generator creates a wide variety of envelope characteristics by implementing a recursive computation algorithm for selected choices of a single curve shape parameter coupled with the use of a collection of timing clocks used to vary the time intervals associated with the attack, decay, and release regions of the musical tone envelope. Provision is made for forcing the release of a tone generator when a limited number of tone generators have been completely assigned in a keyboard musical instrument and a new note key switch is actuated. Note release signals can be ignored until the amplitude curve generator has completed the attack and decay regions for a given tone generator.

Abstract: An instrument for producing musical sounds which includes a keyboard, means connected with the keyboard for producing a plurality of musical sounds and means shifting said keyboard in one or more of a plurality of linear and rotational directions to vary such parameters as pitch, loudness, and tone.

Abstract: A method and circuitry for frequency generation, especially for electronic organs, in which a digital signal is developed by the actuation of an element such as a key of an organ keyboard. The digital signal is converted to a respective voltage signal and the voltage signal is employed to control a voltage controlled oscillator which supplies a signal corresponding in frequency to the actuation of the aforesaid element. An organ provided with a system for frequency generation according to the present invention can be operated monophonically or polyphonically and is capable of producing desirable effects, including celeste and portamento effects.

Abstract: An electronic organ includes logic and a memory for detecting and storing a root note signal identifying a chord which has been either automatically or manually generated. Priority logic, coupled with the memory, passes the lowest root note signal to a tone selection matrix which passes a plurality of tone signals representing the note intervals forming the selected chord. A sequential gating circuit receives all of the tone signals and is responsive to an arpeggio circuit, a strum circuit, or a rhythm unit to gate selected tone signals, one at a time, to the voicing circuitry. When one or more of the tone signals are octavely displaced within the selected chord, disinverting gates are enabled to unfold the chord and cause the tone signals to occur in order of ascending frequency.

Abstract: An electronic circuit connected to and operated by the bass buttons of an accordion to simulate a string bass instrument. The circuit can be disposed in the accordion or remote from the accordion. Each button has a switch associated therewith which couples to means for generating a fixed frequency signal indicative of the actuated button. Signals over a two octave range may be generated and logic circuitry is provided to effectively expand the single octave of available buttons to greater than the single octave such as by a half octave expansion. Output circuitry shapes the output audio signals to allow more or less of the harmonics to pass. A special bass pluck circuit is also provided.

Abstract: A keyboard assignment system for a polyphonic electronic musical instrument employs a small number (typically ten or twelve) of output channels each capable of storing a note identification code used to control generation of a corresponding tone. Output channels are assigned and/or released during an assignment cycle initiated when any keyboard key is depressed or released. During the assignment cycle a keyboard switch matrix and an encoding matrix cooperate to provide sequentially on a data buss note identification codes corresponding to depressed keys. The data buss is connected to all output channels. An identity signal is produced by each output channel which is storing a note identification code corresponding to any which appears on the data buss during the assignment cycle. Assignment logic, responsive to these identity signals, assigns an output channel to each newly depressed key on a priority basis, and releases each output channel which had been assigned to a key which is now released.