AbstractAn electronic musical instrument incorporates a single integrated circuit chip for performing a variety of logical operations for the production of chords and various accompaniment signals automatically, in response to depression of one or two keys within a related portion of the keyboard of the instrument. A multiplexer is employed, in association with the keyboard, to produce a train of signals in response to depression of one or more keys, and one or more function control switches; certain ones of these signals are used to address a plurality of read only memory devices for the generation of the several components needed for the mode of operation
which is selected. In an automatic chord mode, a chord is selected automatically, corresponding to an operated key of the keyboard. The chord components include the root, the third (which may be selectively minored), the fifth, the sixth and the seventh (which can be selected or not). The several chord components are mixed in a stair step network for one output signal, amd may selectively be produced individually for an arpeggio or a strum or both.ClaimsWhat is claimed is:
1. In an electronic musical instrument having a plurality of function selecting switches, a keyboard, tone signal generating means responsive to operation of the keyboardkeys, and an output system responsive to said tone signal generating means, the combination comprising: signal producing means responsive to the operation of one or more keys of said keyboard for producing a digitally coded signal indicative of aselected chord; said tone generating means including N separate tone signal generators, one for each note of an N note chord; first connector means for applying at least a selected portion of said coded signal to each of said tone signal generators,each of said tone signal generators producing an output tone signal, in response to the signal applied thereto, corresponding to a different note of said selected chord; and second connector means, connected to said function switches and to said outputsystem and responsive at least in part to said function switches, for selectively applying the output tone signals from said tone signal generators to said output system.
2. Apparatus according to claim 1, including multiplex means comprising a plurality of single-pole switches associated with the keys of said keyboard, one pole of each of said switches being connected to one of a first set of conductors, thesecond pole of each of said switches being connected to one of a second set of conductors, said first set of conductors connecting in common the first terminal of all said switches associated with keys of the same note name, said second set of conductorsconnecting in common a second terminal of all of said switches associated with keys of the same octave group, means for repetitively scanning said first set of conductors at a first rate, means connected with said second set of conductors for scanningsaid second set of conductors at a second rate which permits the complete scan of all of said first set of conductors while each individual conductor of said second set is being scanned, and means for connecting said second set of conductors to a commonoutput terminal, whereby there is produced at said common output terminal a train of pulses corresponding to operated ones of said switches, occurring in time encoded position in accordance with the operated switches.
3. Apparatus according to claim 2, wherein the scanning means for said first set of conductors incorporates counting means for manifesting a representation of the note name of the key being scanned at any instant, and means for connecting saidstorage means to said counting means, for storing a representation of said note name in response to a pulse received from one of a group of predetermined keys.
4. Apparatus according to claim 2, including pulse adding means connected to said common output terminal, for adding pulses to said pulse train corresponding to unoperated keys which are related to the tone signals produced by said tone signalgenerators.
5. Apparatus according to claim 1, wherein said signal producing means include means for producing a series of separate pulses, one for each operated key of a predetermined group of keys, means responsive to a first of said pulses for initiatinga window period, means responsive to another of said pulses for terminating said window period, and means for manifesting a window signal during said window period.
6. Apparatus according to claim 5, including means responsive to said window signal and to one of said pulses occurring during said window period for producing a gating pulse, and means for connecting said gating pulse to said storage means,manifesting means for manifesting a representation of the note name of the key represented by said gating pulse and means for connecting said manifesting means to said storage means to cause said storage means to store said representation at the time ofsaid gating pulse.
7. Apparatus according to claim 6, including means for identifying the first of said pulses occurring during a window period and for producing said gating pulse in response thereto.
8. Apparatus according to claim 6, including means for identifying every one of said pulses occurring during said window period and producing said gating pulse in response thereto, whereby said storage means is caused to store the representationof the key corresponding to the last pulse received within said window period.
9. Apparatus according to claim 1, including manifesting means responsive to said signal producing means for manifesting a representation of the note name of an operated key of said keyboard, storage means connected to said manifesting means andto said signal generating means and operative to store the representation manifested by said manifesting means, means connecting all of said tone signal generators to said storage means, said tone signal generators being responsive to the output of saidstorage means for generating tone signals having frequencies bearing a predetermined relation to the note name representation stored in said storage means.
10. Apparatus according to claim 9, wherein each of said generators comprises a programmable frequency synthesizer having a read only memory, addressing means for said read only memory, and a programmable divider connected to said read onlymemory, means for connecting said storage means to said addressing means for addressing a section of said read only memory corresponding
to the representation stored in said storage means, said divider being programmed by signals produced by said readonly memory in accordance with signals supplied to said addressing means, and means for connecting said programmable divider to a source of clock pulses, whereby said programmable divider produces an output signal having a frequency which is a quotientof the frequency of said clock pulses.
11. Apparatus according to claim 9, including a decoder connected to said storage means for producing an individual signal on one of a plurality of output lines corresponding to the note name, the representation of which is stored in saidstorage means, each of said generators having a plurality of input terminals connected in common to said plurality of output lines, and each of said generators being adapted to respond to a single energized one of said plurality of output lines toproduce a tone signal having an individual frequency.
12. Apparatus according to claim 1, including a plurality of divider units, one for each of said tone signal generators, said divider units being connected between each of said tone signal generators and said output system, manifesting means formanifesting a representation of the note name of a key corresponding to a pulse of said pulse train, means for connecting said manifesting means to said storage means to cause said storage means to store said representation, and means connecting saidstorage means with said divider units for controlling the operation of said divider units in accordance with said representation.
13. Apparatus according to claim 1, wherein two of said generators simultaneously produce two tone signals corresponding to two different keys of the keyboard which are simultaneously depressed.
14. Apparatus according to claim 1, wherein said signal producing means includes means for identifying a single operated key of said keyboard and means reponsive to said last named means for operating all of said generators.
15. Apparatus according to claim 14, wherein said last named means causes said generators to produce tone signals corresponding to the root, third and fifth of a selected chord, said tone signals each being produced by a separate one of saidgenerators.
16. Apparatus according to claim 15, including means for causing one of said generators for producing a tone signal corresponding to the seventh of said selected chord, and means responsive to one of said function selecting switches forselectively producing an output signal containing said tone signal corresponding to the seventh of the chord.
17. Apparatus according to claim 15, including means responsive to one of said function selecting switches for selectively causing one of said generators to produce a tone signal corresponding to the minor third of said selected chord.
18. Apparatus according to claim 15, including strum means responsive to one of said function selecting switches for causing said tone signals to be produced at an output terminal successively in predetermined order.
19. Apparatus according to claim 18, including a plurality of tone signal output terminals, a plurality of gates for connecting individual ones of said generators to said output terminals when said one function selecting switch is closed, aplurality of keying signal output terminals, and means for providing pulses sequentially to said keying signal output terminals.
20. Apparatus according to claim 19, wherein said last named means comprises a clock signal generator, a plurality of gates each having an output connected to one of said keying signal output terminals, and pulse distributing means forsuccessively applying pulses from said clock signal generator to said keying signal output terminals.
21. Apparatus according to claim 20, including bistable means, means for connecting an input pulse to said bistable means for setting said bistable means to a first state, means connecting said bistable means to said pulse distributing means forinitiating operation of said pulse distributing means, and means for resetting said bistable means at the end of one cycle of pulses applied to said keying signal output terminals.
22. Apparatus according to claim 21, including means for selectively producing at one of said tone signal output terminals a tone signal corresponding to the seventh of a selected chord, and a corresponding signal at one of said keying signaloutput terminals, and means for resetting said bistable means following production of said corresponding signal.
23. Apparatus according to claim 21, including means for resetting said pulse distributing means with said bistable means, whereby said strum output means initiates each cycle of operation with production of a pulse at the same keying signaloutput terminal.
24. Apparatus according to claim 14, including a tone signal output terminal, and means for sequentially connecting individual ones of said tone signal generators to said tone signal output terminal in ascending and descending order, relative tothe pitches of said tone signals which are connected to said tone signal output terminal.
25. Apparatus according to claim 24, including multiplexer means for connecting said generators one at a time to said tone signal output signal, a bistable device, means for sequencing said multiplexer means in ascending order when said bistabledevice is in one state and for sequencing said multiplexer means in descending order when said bistable device is in its other state, and means for alternately setting and resetting said bistable device, respectively, when the highest and lowest pitchesof said tone signals are connected to said tone signal output terminal.
26. Apparatus according to claim 25, including means for selectively resetting the sequencing means for said multiplexer means to begin a new cycle of operation with the connection of a predetermined tone signal to said tone signal outputterminal.
27. Apparatus according to claim 26, including means for manifesting a control signal when the identity of said single operated key is changed, and selectively operable means responsive to said control signal for resetting the sequencing meansfor said multiplexer.
28. Apparatus according to claim 26, including means for producing a signal in response to non-operation of one of said function selecting switches, and means responsive to said control signal for resetting the sequencing means for saidmultiplexer means.
29. Apparatus according to claim 24, wherein said tone signal generators produce tone signals corresponding to the root, third and fifth of a selected chord, and including first and second frequency divider stages for each of said root, thirdand fifth
tone signals, to produce the second and fourth subharmonics of each of said tone signals, and means for connecting to said multiplexer means each of said tone signals and each of said subharmonics, whereby nine tone signals are connected tosaid tone signal output terminal.
30. Apparatus according to claim 1, including a storage device for each of said function selecting switches, and cyclically operable means for setting each of said storage devices for each cycle in which its respective switch is closed andresetting it for each cycle in which its respective switch is open.
31. Apparatus according to claim 30, including bistable means connected to one of said storage devices, means for setting said bistable means when said storage device is set, means for resetting said bistable means, means producing a controlsignal when the identity of said one operated key is changed, and means for resetting said bistable means in response to said control signal.
32. Apparatus according to claim 14, wherein one of said function selecting switches is closed for execution of a latch operation, bistable means, means for producing a control signal in response to the occurrence of said one signal and forterminating the production of said control signal if no key within a predetermined group of keys of the keyboard is operated, means connected to receive said control signal and responsive to the existence of said control signal while said latch selectingswitch is closed for setting said bistable means, and means connected to said bistable means for enabling said output signals only while said bistable means is set, and means responsive to the opening of said latch-selecting switch for disabling saidoutput signals.
33. Apparatus according to claim 1, wherein said signal producing means and said tone generating means and said first connector means are all embodied in a single integrated circuit.
34. Apparatus according to claim 1, including logic means connected to said tone signal generators for producing a plurality of output tone signals in a predetermined order, said logic means being connected to said function selecting switchesfor selectively producing said output tone signals in a selected one of a plurality of octaves.
35. In an electronic musical instrument having a keyboard, tone signal generating means and an output system connected to said tone signal generating means, said tone signal generating means including a plurality of tone signal generators, thecombination comprising: a source of clock pulses; a programmable frequency generator for each tone signal generator, said programmable frequency generator having a coding means adapted to generate a predetermined coded output in response to each codedsignal input applied thereto, and a programmable divider for each tone signal generator connected to the output of each said coding means and to said source of clock pulses for dividing the pulse repetition rate of said clock pulses in accordance withthe coded output from said coding means; control means operative in response to the operation of at least selected keys of said keyboard for applying a predetermined coded input to said coding means; and connector means responsive to the output fromsaid programmable divider for applying a selected tone signal to said output system.
36. Appartus according to claim 35, wherein said control means includes decoder means for producing one of a plurality of coded signals in response to an operated key of said keyboard, said programmable frequency generator being resonsive tosaid one output signal to produce a harmonic of a frequency associated with said operated key.
37. Apparatus according to claim 36, wherein said connector means includes a plurality of cascaded frequency divider stages, and selecting means responsive to operation of a key of said keyboard for selecting the number of stages in saidplurality.
38. Apparatus according to claim 37, including means connected to said selecting means for controlling said selecting means in accordance with the signals supplied to said coding means.
39. Apparatus according to claim 37, including means responsive to the octave location of the operated key of the keyboard for controlling said selecting means.
40. Apparatus claimed in claim 35, wherein the coding means of each of said tone signal generators is adapted to generate a different predetermined coded output in response to a given coded input applied thereto, and wherein said control meansis operative to apply the same predetermined input to the coding means of each of said tone signal generators in response to the operation of a selected key.
41. Apparatus according to claim 40, wherein said operated key of the keyboard is a chord key; said control means including decoder means for producing a coded signal representative of the root note of the chord corresponding to an operated keyof the keyboard; a first of said tone signal generators being operative in response to said coded signal for producing a tone signal output corresponding to the selected root note; a second of said tone signal generators being operative in response tosaid coded signal for producing a tone signal corresponding to the third of the selected chord; and a third of said tone signal generators being operative in response to said coded signal for producing a tone signal output corresponding to the fifth ofthe selected chord.
42. Apparatus according to claim 41, wherein a fourth of said tone signal generators is operative in response to said coded signal for generating a tone signal output corresponding to the sixth of the selected chord.
43. Apparatus according to claim 41, wherein a fourth of said tone signal generators is operative in response to said coded signal for generating a tone signal output corresponding to the seventh of the selected chord.
44. Apparatus according to claim 41, including means for providing an additional input to the coding means for the tone signal generator producing the tone signal corresponding to the third of the selected chord, said coding means generating afirst output when no signal is applied to said additional input and another coded output when a signal is applied to said coded input; said programmable divider for the tone signal generator producing the tone signal corresponding to the third of theselected chord being operable responsive to one of said coded outputs for producing an output corresponding to the major third of the selected chord and responsive to the other of said coded outputs for producing an output representative of the minorthird of the selected chord.
45. Apparatus according to claim 35, including means for providing an additional input to said coding means, said coding means generating a first output to said programmable divider when a signal is not present on said additional input andgenerating a second output to said programmable divider when a signal is present on said additional input.
46. Apparatus according to claim 35, wherein said control means includes gating means operative for applying either a first predetermined coded input to the coding means or a second predetermined coded input to said coding means, said first andsecond predetermined coded inputs being generated in response to the operation of different keys of said keyboard; and means controlling said gating means to apply one or the other of said predetermined inputs to the coding means.
47. Apparatus according to claim 35, wherein said coding means comprises a read only memory.
48. In an electronic musical instrument having a keyboard with playing keys, tone signal generating means and an output system connected to said tone generating means, the combination comprising manifesting means for manifesting a representationof an operated playing key of said keyboard, said tone signal generating means being responsive to said manifesting means for producing a plurality of tone signals at separate outputs, a plurality of separate strings of cascaded frequency divider stagesinterconnected between each of said outputs and said output system, and control means responsive to said manifesting means for selecting the number of stages in each said string.
49. Apparatus according to claim 48, wherein said manifesting means produces a control signal representative of the note name of said operated key, and said control means is responsive to said control signal.
50. In an electronic musical instrument having a keyboard with playing keys, tone signal generating means and an output system connected to said tone signal generating means, multiplexer means for developing one note-indicating signal inresponse to operation of each one of a predetermined group of said playing keys, and signal producing means responsive to said note-indicating signal for successively producing a plurality of additional note-indicating signals, said additionalnote-indicating signals indicating notes which are components of a selected chord, the root of which is identified by said one note-indicating signal, and pulse producing means for producing a first pulse in response to said one note-indicating signal,said multiplexer means comprising means responsive to said first pulse for producing further note-indicating signals corresponding to a plurality of keys of said keyboard having the same note name, and means for supplying at an output terminal only oneof said further note-indicating signals for each component of said selected chord.
51. In an electronic musical instrument having a keyboard with playing keys, tone signal generating means and an output system connected to said tone signal generating means, means for developing one note-indicating signal in response tooperation of each one of a predetermined group of said playing keys, and signal producing means responsive to said note-indicating signal and having a single output terminal for producing a plurality of additional note-indicating signals, said additionalnote-indicating signals indicating notes which are components of a selected chord, the root of which is identified by said one note-indicating signal, each of said note-indicating signals being produced at said single output terminal at a predeterminedtime representative of an associated playing key, said signal producing means including a plurality of delay means for delaying one note-indicating signal by different time intervals, and for producing said additional note-indicating signals at theoutputs of said delay means.
52. Apparatus according to claim 50, wherein said developing means produces a note-indicating signal for every operated one of said predetermined groups of keys, and means for producing all of said note-indicating signals at a single outputterminal.
53. Apparatus according to claim 51, wherein said plurality of delay means are connected in cascade.
54. An electronic musical instrument having a keyboard, tone signal generating means and an output system connected to said tone signal generating means, said tone signal generating means including coding means connected with said keyboard forproducing a coded signal in response to operation of the keys of said keyboard, and a digital programmable generator responsive to said coding means for generating a tone signal corresponding to the third component of a chord, the root of which isidentified by operation of a key of said keyboard, and selectively operable means connected to said programmable frequency generator for causing said generator to selectively generate the major or minor third of said chord.
55. Apparatus according to claim 54, wherein said coding means is connected with said programmable frequency generator by a plurality of control lines, and means responsive to operation of said selectively operable means for altering a signal onone of said control lines.
56. In an electronic musical instrument having a plurality of function selecting switches, a keyboard, tone signal generating means responsive to operation of the keyboard keys, and an output system connected to said tone signal generatingmeans, the combination comprising: multiplex means connected with said keyboard for producing, in repetitive cycles, a train of time encoded pulses at pulse times within each said cycle responsive to operation of keys of said keyboard; window meansconnected with said multiplex means for identifying a window period defined by a predetermined range of said pulse times, during each said cycle; storage means connected with said multiplex means and with said window means for storing an indication thatone of said keys has been operated, said storage means manifesting an output signal indicative of said key; a plurality of tone signal generators connected with said storage means and responsive thereto for simultaneously producing a plurality of tonesignals each having a predetermined relationship to the operated key; a plurality of gates connected to receive said tone signals from said tone signal generators and for selectively passing said tone signals to said output system; and logic meansconneced with said gate means and with at least one of said function selecting switches, for selectively enabling certain ones of said gates in response to operation of said one function selecting switch.
57. In an electronic musical instrument having a keyboard with playing keys, tone signal generating means and an output system connected to said tone signal generating means, means for developing a note-indicating signal in response to operationof each one of a predetermined group of said playing keys, and signal producing means responsive to said note-indicating signal for producing a plurality of additional note-indicating signals, said additional note-indicating signals indicating noteswhich are components of a selected chord, the root of which is identified by said one note-indicating signal, and pulse producing means for producing a first pulse in response to said one note-indicating signal, said developing means comprising meansresponsive to said first pulse for producing further note-indicating signals corresponding to a plurality of keys of said keyboard having the same note name, and means for supplying at an output terminal only one of said further note-indicating signalsfor each component of said selected chord.DescriptionBACKGROUND
1. Field of the Invention
The present invention relates to electronic musical instruments, and more particularly to electronic organs having apparatus for automatically producing chords and harmony and a variety of bass patterns for accompanying a melody played on theinstrument.
2. The Prior Art
Several attempts have been made to produce organs which generate automatically chords and harmony and bass patterns, to accompany a melody played on the instrument. While many of these work well for the purposes intended, they are eitherrelatively limited in their performance, or relatively complicated and expensive, requiring a large number of parts.
Accordingly, there is a need for an improved circuit which employs fewer parts than heretofore used, but which is able to perform all of the desired functions in a simple and economical manner.
BRIEF DESCRIPTION OF THE INVENTION
It is a principal object of the present invention to provide a control circuit for an electronic musical instrument whereby a number of control functions may be carried out by integrated circuitry incorporated in a single integrated circuitpackage.
Another object of the present invention is to provide an integrated circuit package for performing a variety of control functions in association with an electronic musical instrument, in which such package incorporates a number of read onlymemories, each associated with a frequency synthesizer unit, so that the frequency synthesizer unit produces a rectangular wave signal having a pulse repetition rate uniquely associated with each individual address of the read only memory.
Another object of the present invention is to provide an integrated circuit package for an electronic musical instrument incorporating a plurality of read only memories and a plurality of frequency synthesizers, each associated with one of theread only memories, so that each of the read only memories may be programmed differently so as to uniquely produce a signal having a pulse repetition rate related to an individual component of a musical chord.
Another object of the present invention is to provide such an integrated circuit in which the data used for addressing all of said read only memories is derived from a stream of pulses resulting from multiplexing a plurality of switches, some ofwhich are operated in response to depression of keys of the keyboard of the musical instrument.
These and other objects and advantages of the present invention will become manifest by an inspection of the accompanying drawings and the following description.
In one embodiment of the present invention there is provided an integrated circuit formed of a single chip of semiconducting material, incorporating multiplexing means for producing a train of pulses in response to operation of a plurality ofswitches, some of which are operated in response to depression of keys of the keyboard of a musical instrument, a plurality of read only memories responsive to addresses derived from said train of pulses and each being operative to produce a uniquesignal having a pulse repetition rate corresponding to an individual element of a chord associated with a depressed key, a plurality of frequency dividers connected to receive the signals produced by said read only memories, a logic network forcontrolling the operation of said divider chains to produce output signals having a controlled pitch, and control means for controlling the timing at which the output signals are produced.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will now be made to the accompanying drawings, in which:
FIG. 1 is a functional block diagram of an electronic musical instrument incorporating an illustrative embodiment of the present invention;
FIG. 2 is a functional block diagram in more detail of a portion of the apparatus illustrated in FIG. 1;
FIG. 3 is a schematic diagram of a portion of a keyboard and a plurality of function control switches associated with the logic unit of FIG. 1;
FIG. 4, comprising FIGS. 4a through 4f, constitutes a schematic block diagram in more complete detail of a portion of the apparatus of FIG. 1;
FIG. 5 is an illustration of how FIGS. 4a-4f are interconnected;
FIG. 6-10 are functional block diagrams of the divider control logic unit 272 and the divider units for the various chord components; and
FIG. 11 is a functional block diagram of one of the tone signal generators.
DESCRIPTION OF THE PREFERRED EMBODIMENT
General
Referring first to FIG. 1, the musical instrument of the present invention incorporates a keyboard 10 which is connected by a number of lines 12 with a logic unit 14. A power supply 16 provided with a line chord 17 is provided to supplyelectrical power to the logic unit 14, and it processes information received from the keyboard and from a plurality of auxiliary switches (not shown ) and produces a plurality of outputs on a number of output lines 18. The output lines 18 are connectedto inputs of a plurality of keyers 20, which also receive power from the power supply 16, and the outputs of the keyers 20 are passed through one or more voicing units within a voicing section 22; the output of the voicing section 22 is amplified by anamplifier 24 and is supplied to a loudspeaker 26. The amplifier 24 is also supplied with power from the power supply 16.
Not shown in FIG. 1 is a plurality of auxiliary function control switches, such as the normal switches or tablets usually associated with electronic organ keyboards. A variety of such switches are provided and function in the normal way
tocontrol the amplifier 24 and the voicing section 22, as well as the keyers 20. They also control the logic unit 14, in ways which are described hereinafter. Of the units in FIG. 1, only the logic unit 14 is not conventional. All of the other unitscorrespond to known apparatus available in the art, and any of a number of different constructions may be employed.
In FIG. 2, a general block diagram of the logic unit 14 and its associated structure is illustrated.
A clock signal generator 28 is provided for producing a series of clock pulses on a line 30, for regulating operation of the logic unit. The line 30 is connected to the input of a multiplexer 32, which is connected to a number of differentfunctional units. In addition to the keyboard 10, the multiplexer 32 is connected to a plurality of function control switches 34, a plurality of note latches 36, a plurality of function latches 38, and a serial data unit 40. The function of themultiplexer 32 is to examine the state of the keys of the keyboard 10 and the various switches of the functional switches 34, and to produce signals for controlling the latches 36 and 38 so that the latches are set in accordance with the depressed keysof the keyboard and the operated function control switches.
The serial data unit 40 is responsive to the multiplexer 32 an also to the function latches 38 for producing on an output line 42 a pulse train including a pulse for at least one of the operated keys of the keyboard 10, as well as some additionalpulses which are inserted under control of the serial data unit 40. The pulses on the line 42 are passed to other apparatus (not shown) and employed to produce musical sounds corresponding, in frequency, to the time position of each of the pulses in thetrain.
The note latches 36 provide an output on the line 43 which is applied to a plurality of generators 44-48. The generator 44 produces signals corresponding in frequency to that of the root of a given chord, a generator 45 produces signalscorresponding to the musical third of the chord, and the generators 46-48 produce signals having frequencies corresponding to the musical fifth, sixth and seventh of the chord.
The generators 44-48 each produce an output which is connected to an individual divider unit of a set of such units 50-54. The outputs of the divider units 50-54 are all connected to inputs of an operation control unit 56, and the operationcontrol unit 56 in turn controls operation of the divider units 50-54 by means of signals on lines illustrated in FIG. 2 by lines 58-62.
The operation control unit 56 also receives signals from the rhythm unit 66 over a line 68. A number of outputs are produced by the control unit 56, as follows. A line 71 produces a chord output corresponding to a chord produced by operation ofthe control unit 56. A plurality of lines illustrated by the line 72 in FIG. 2 produces a number of signals in time succession for producing a strummed effect in either a high or low pitch. A plurality of lines indicated by the line 73 in FIG. 2produce signals which are used for providing bass accompaniment, and the plurality of lines signified by the line 74 in FIG. 2 produce a plurality of signals useable in connection with an arpeggio operation.
The apparatus illustrated in FIG. 2 is capable of operation in two different modes, which are described in more detail hereinafter in connection with FIG. 4. It is useful, however, to summarize the features of the two modes of operation here, inconnection with the more generalized diagram of FIG. 2.
The first mode of operation will be referred to as the high-low mode. When this mode of operation is selected, two of the keys of the keyboard are effective to select two tones which are produced in the output. The two keys which are effectiveare the highest and lowest keys operated within a given area of the keyboard; that is, the rightwardmost and the leftwardmost ones of all of the operated keys within that area, if more than two are operated. The designated area comprises the lowesttwenty-eight keys of the keyboard 10. The two tones which are produced in response to operation of these two keys are produced at separate outputs simultaneously, but may be made to sound alternately under control of pulses from the rhythm unit 66.
The second mode of operation is the automatic chord mode, in which only a single key of another given portion of the keyboard (vis., the lowest twelve keys) is effective to control the operation control unit. That signal key is the uppermost (orrightmost) one of the operated keys (of the lowest twelve keys) if more than one are operated, and the position of this key designates a particular chord name, such as an A chord, a C chord, etc. The tone corresponding to the root of this chord, as wellas the tones for the third and fifth, are simultaneously passed to the output and made available at the chord output 71. An operator may selectively decide to minor the third, producing a minor chord instead of a major chord, and the operator may alsodecide to selectively add the seventh to the cord, producing chord, dominant seventh chord, major or minor.
The chord selected by means of a single key, in the automatic chord mode, is outputed continuously and may also be outputed in one or both of two discontinuous patters, hereinafter referred to as the strum signal output and the arpeggio signaloutput. When the strum signal output is selected, signals from the rhythm generator supplied to the operation control unit 56, cause the production of the several tones of the chord to be sounded, one at a time, in upward progression, just as if thestrings of a stringed musical instrument were being strummed by a player. When the arpeggio signal output is selected, tones representing the root, third and fifth of the selected chord, in three separate octaves, are generated by the logic unit 56, andare sounded in ascending and then descending fashion, continuously. Both the strum and the arpeggio signal outputs begin with the sounding of the root tone. The strum signal outputs may be selected to occur in either of two octave ranges, a high or lowoctave, under the control of one of the function switches 34.
Bass signals produced on the line 73 may consist of a variety of different bass patterns. One pattern is alternately sounding tones corresponding to the highest and lowest ones of a plurality of keys which are operated in a designated portion ofthe keyboard, just as in the high-low mode, described above. In another pattern, the root and fifth of a particular chord are alternately sounded in the bass. In yet a third pattern, a walking bass is produced, in which tones corresponding to the root,third, fifth, sixth and seventh of the selected chord are produced in succession, in time with pulses received from the rhythm unit 66, ascending and descending.
A latch operation may be selected, by operation of one of the function controlling switches 34, which causes the operation of the operation control unit 56 to persist, even after the depressed keys of the keyboard have been released. When thelatch mode is not selected, the output signals produced by the operation control unit 56 terminate when the depressed keys are released.
Reference will now be made to FIG. 4, for a more complete description of logic unit 14 and its associated apparatus. FIG. 4 is made up of six sections, viz., FIGS. 4a-4f, assembled as illustrated in FIG. 5.
Clock Pulses
Clock pulses are generated by a divider 100, illustrated in FIG. 4b. A terminal 102 is connected to an external source of high speed clock pulses, and a line 104 connect the terminal 102 to the input of the divider 100. The divider 100 produceson two lines 105 and 106 normal and inverted clock pulses, which are distributed throughout the remainder of the system where they are needed. The high speed clock pulses applied to the terminal 102 are used in connection with the frequencysynthesizers, as described hereinafter.
Multiplexer, Keyboard and Function Switches
The line 105 is connected to the input of a counter 108 (FIG. 4a), which forms a part of the multiplexer 32 (FIG. 2). The counter 108 is a binary counter having four stages connected so as to have a radix of twelve. That is, the counter 108 hastwelve different states, which are repeated in endless succession as input pulses are received from the line 105.
Four output lines are connected individually to the four stages of the counter, and signals on the output lines 110 represent the current state of the counter 108, in binary representation. The counter 108 counts consecutively from zero througheleven, and the next clock pulse received resets the counter 108 to zero, whereupon the operation is repeated. Overflow pulses are produced on an output line 112 each time the counter 108 is reset to zero, and the line 112 is connected to the input of acounter 114.
The counter 114 is a three-stage binary counter, connected to have a radix of six, and a plurality of lines 116 are connected individually to its three stages. The state of the counter 114 is incremented by one for each complete cycle of thecounter 108, so that the signals on the output lines 110 and 116 form a cyclically repeating pattern for every seventy-two clock pulses. Seventy-two clock pulses constitute a single cycle of operation of the multiplexer, during which the status ofseventy-two switches is sensed, to derive information relative to operation of the instrument.
The output lines 110 of the counter 108 are connected to four input lines of a one-of-twelve decoder 118, which functions to decode the binary representation of the signals on the output lines 110 and energize one of twelve output lines 120, inaccordance with the state of the counter 108. The twelve output lines 120 are designated in FIG. 4a as the "X" outputs and are numbered zero through eleven, to indicate the state of the counter 108 when each respective X line is energized.
The X lines 120 are connected to the keyboard switches and the function switches, through diodes 121, as illustrated in FIG. 3. The keyboard 10 is represented schematically, and under each key of the keyboard 10 there is a keyboard switch 124which is actuated when its corresponding key is depressed. Each of the switches 124 is a normally open, single-pole, single-throw switch. One terminal of the switch is connected to one of the X lines 120, and the switches 124 which are associated withcorresponding keys of the keyboard 10 in different octaves are connected to the same X line 120. Thus, the common poles of all of the A keys are connected together, through diodes 121, to one of the X lines 120, the common poles of all of the B-flatkeys 124 are connected in common to a second of the X lines, etc.
The other pole of each of the switches 120 is connected to one of several Y lines 126. The Y lines 126 are connected to the switches 124 in accordance with their octave location relative to the keyboard. Thus, the first of the Y lines 120 isconnected in common to the second terminal of the first twelve switches 124 (for the highest octave), the next Y line is connected in common to the next twelve switches 124, etc. A total of sixty-four keys are provided in the keyboard 10, and there aresixty-four switches 124 connected in the manner partially illustrated in FIG. 3. The last of the Y lines 126 is connected to four switches 124 of the lower left-hand end of the keyboard 10 (not shown), and to eight function control switches 129 through136. The Y line is connected to the second pole of the switches 129 through 136, with the first terminal of the switches 129 through 136 connected to the last eight of the X lines 120.
In operation, one of the X lines is energized with a signal in the manner described above, in accordance with the state of the counter 108. This signal is then applied to all of the switches associated with keys for the same note name and, insome cases, to one of the function control
switches 128-136. Each of these switches 124 which is closed completes a path from the energized X line to one of the Y lines 126. The Y line which is energized by any closed switch depends upon the positionof that switch in the keyboard. A switch in the highest octave will energize the first Y line, a switch in the second highest octave will energize the second Y line, etc. If the energized X line is connected to a closed function control switch, the lastof the Y lines is energized. For any given combination of X and Y lines there is one and only one switch which can complete a path, and this one switch may be either a keyboard switch 124 or a function control switch 129-136.
The Y lines 126 are connected to six inputs of a six-channel multiplexer 128 (FIG. 4a). The multiplexer 128 receives its control inputs from the output lines 116 of the counter 114, and functions to connect one and only one of the Y lines 126 toan output 130 of the multiplexer 128, in accordance with the state of the counter 114. The output line 130 thus contains, for each cycle of operation of the multiplexer 32, a train of pulses, including one pulse for each of the operated switches 124 and129-136. The pulses are encoded in time position representative of the switches which are operated. Hereinafter the seventy-two pulse times of each cycle will be referred to as pulse time 1 through pulse time 72. Pulses occurring during the firstsixty-four pulse times represent operated keys of the keyboard, while the last eight pulse times represent operated ones of the function switches.
Note Latches
The identification of the note corresponding to a pulse within the first sixty-four pulse times corresponds to the binary coded output on the lines 110 at the timme of occurrence of such pulse on the line 130. Similarly, the octave of such note(the octave of the keyboard in which its associated key is located) is identified by the binary code on the output lines 116. Thus, the simultaneous condition of the outputs 110 and 116 uniquely represents the specific switch which is being scanned atany instant. These seven lines, viz., the four lines 110 and the three lines 116, are connected to seven inputs of a group of A latches 132 and to seven inputs of a group of B latches 134. The A latches 132 are provided with a set input 136, and, whenthe set input is energized with a set pulse, the latches 132 are set in accordance with the signals then present on the lines 110 and 116. That is, a high level on one of the lines 110 and 116 at the set pulse time causes its respective latch to be setin one state, and a low level then causes it to be reset to the opposite state. A similar set terminal 138 is provided for the B latches. The set inputs 136 and 138 are energized with set pulses at specific times, as described more fully hereinafter.
Seven output lines 140 connected to the A latches continuously manifest voltage levels representative of the states of the individual latches 132. Similarly, seven output ines 142 manifest the states of the B latches 134. The lines 140 areconnected to seven inputs of a group of C latches 144, which is provided with a set input 136. When the set input 136 is energized, the C latches 144 are set in accordance with the signals on the lines 140. Similarly, the lines 142 are connected toseven inputs of a group of D latches 148, which has a set input terminal 150. When the set input terminal 150 is energized, the D latches 148 are set in accordance with the signals on the lines 142. The set input terminals 146 and 150 are energizedwith set pulses together by signals on a line 152, derived in a manner described more fully hereinafter.
When the C and D latches are set, outputs on lines 154 and 156 manifest the states of these latches. The four lines 154, which carry signals derived initially from the outputs of the counter 108, are connected to four inputs of a one-of-twelvedecoder 158, which functions to energize one of twelve output lines 160, in accordance with the binary representation of the signals on the lines 154. Similarly, the four of the lines 156, which also manifest information originally derived from thecounter 108, are connected to four inputs of a one-of-twelve decoder 162, which manifests an output on one of its twelve output lines 164, in accordance with the binary representation of its four inputs lines.
Tone Signal Generators
The signals on the lines 110, produced by the counter 108, represent in binary form the note name of the key connected at that moment to the energized one of the X lines 120. Accordingly, the one of the twelve lines 164 which is energized at anygiven time corresponds to the note name of the operated key, the representation of which is stored in the D latchs 148. Similarly, the energized one of the lines 160 corresponds to the note name of the operated key, the representation of which is storedin the C latches. The times of setting of the C and D latches are described hereinafter.
The twelve lines 164 are connected to twelve inputs of a root tone signal generator 44, which is made up of a read only memory or ROM 166 and a programmable frequency synthesizer 168. The ROM is a read only memory having twelve storagelocations, which are addressed, respectively, individually, by the twelve input lines 164. Addressing any one of the twelve storage locations causes the read only memory to supply a divisor control signal to the PFS 168, which controls the effectivedivision rate of the PFS. The PFS 168 receives as a dividend signal input a high speed clock from the terminal 102, over the lines 104 and 170. It produces an output signal on a line 172, which output signal corresponds to a quotient of the high speedclock frequency, in accordance with the divisor signal supplied by the ROM 166. This output signal has a pulse repetition rate corresponding to the note name of a
key of the keyboard 10. Assuming that depression of an A key resulted in setting the Dlatches 148, the signals on the lines 156 correspond to the note "A," and the one output line 164 of the decoder 162 corresponds to the note name "A". This line addresses the "A" storage location of the ROM 166, which controls the PFS 168 so that thehigh frequency clock signal on the line 170 is divided by an appropriate divisor so as to produce on the line 172 a continuous train of pulses having a pulse repetition rate corresponding closely to a harmonic of 440 Hz, which corresponds with the notename "A."
When the D latches 148 are set in response to a different key, a different output line 164 is energized, and a different storage location of the ROM 166 is addressed, producing a different divisor input to the PFS 168 with a correspondinglydifferent pulse repetition rate on the output line 172. Thus, the particular energized one of the output lines 164 causes the root tone signal generator 44 to produce on its output line 172 a continuous pulse train having a pulse repetition ratecorresponding to a harmonic of the note of the depressed key.
The output lines 164 are also connected to the twelve inputs of the other four tone signal generators 45-48. The connection of the lines 164 to the fifth tone signal generator 56 is made through a plurality of gates 174. The gating network 174incorporates twelve sets of gates, one for each of its set of twelve output lines 176. In addition to the twelve lines 164, the twelve lines 160, produced by the decoder 158, are also presented to the gates 174. Only the gates associated with the lines164a and 160a will be described in detail, since all the other gates are identical.
An AND gate 178 has one input connected to the line 164a and the other input connected to a control line 180. A second AND gate has one inut connected to the line 160a from the decoder 158, and its second input is connected to a control line184. The control lines 184 and 180, hereinafter referred to as the "M" line and the "M" line, present complementary signals, so that one and only one of the gates 178 and 182 is conditioned to pass either the signal on the line 164a or the signal on theline 160a. The outputs of the two AND gates 178 and 182 are each connected to two inputs of an OR gate 186, the output of which is connected to the output line 176a. Accordingly, at all times either the lines 164 or the lines 160 are connected to thetwelve inputs of the fifth tone signal generator 46, depending upon the condition of the lines 180 and 184.
Each of the generators 45-48 are provided with an ROM and a PFS, just as described in connection with the generator 44. The address coding of each of the ROM's is different, however, so that the frequency or pulse repetition rate of the tonesignals produced by the PFS's of the several generators are different. Assuming that the line 164a corresponds to an "A," the pulse repetition rate of the output signal produced by the root generator 44 on the output line 172 is, as described, aharmonic of 440 Hz, corresponding to the note name "A." The third for the chord of A is C鈾? and, when the line 164a is energized, the output line 188 of the third generator 45 produces a continuous train of pulses having a pulse repetitionrate corresponding to C鈾? Similarly, the pulse trains produced on the output lines 190, 192 and 194, the fifth, sixth and seventh generators 46-48, correspond to the pulse repetition rates for the notes E, F鈾?and G. In each casethe address coding of the ROM associated with each generator is such that when the line 164a is energized, continuous pulse trains at the pulse repetition rates or frequencies corresponding to various parts of the chord of A are produced. The pulserepetition rate of the signal on the line 194 corresponds to the seventh of the A chord, which is the note normally included in a dominant seventh chord.
Instead of the line 164a, if the line 164b is energized, a different set of frequencies, corresponding to parts of the chord of B-flat, is produced on the output lines of the generators 45-48. It is therefore apparent that an entire set offrequencies making up a chord is simultaneously produced by the several tone signal generators in response to the setting of the D latches 148. The manner in which these several frequencies are employed is dependent upon operation of the functionswitches and the operation control unit, as described hereinafter.
The third tone signal generator 45 is unlike the generators 44 and 46-48 in that its ROM 196 has an additional input line 198. When the line 198 is energized, it operates effectively to cause the ROM 196 to function as if a different one of theinput lines 164 were energized. This causes the ROM 196 to supply a different divisor signal to the PFS of the tone signal generator 45, so that a signal having a pulse repetition rate corresponding to a minor third is produced on the output line 188,instead of the major third signal normally produced. Then, when the line 164a is energized, to designate the A chord, and the line 198 is also energized, the desired output from the third generator 45 corresponds to C (the minor third of the A chord)instead of C鈾? C is the major third in the G鈾?chord, represented by the line 1641, and so energization of the minor selection line 198 causes the ROM 196 to operate as if the line 1641 were energized instead of the line 164a. Asimple gating circuit is effective to accomplish this result, and the specific circuitry employed is, therefore, not discussed in detail. It is identical to the gating circuit 174, using the line 194 to energize one set of gates, and an inverter havingits input connected to the line 195 to drive the other set of gates.
Set Pulses for Note Latches
The note latches 132 and 134 require set pulses to be applied to their inputs 136 and 138 so that the latches can be set in accordance with a given note and octave. The generation of the signals applied to these inputs will now be described.
As described above, all of the pulses representative of the operation of the keys of the keyboard 10 occur during the first sixty-four time periods of each cycle of operation. Only pulses which occur during a portion of this group of timeperiods are used to provide information to the A and B latches 132 and 134. Specifically, in the hi-low mode of operation, only pulses occurring during pulse times 36 through 64 function to operate the A and B latches, while in the automatic chord modeof operation, only pulses occurring between pulse times 52 and 64 are effective for this purpose.
1. Hi-Low Mode
An AND gate 200 (FIG. 4d) has three inputs which are connected, respectively, to one of the outputs (viz., 116b) of the counter 114 (FIG. 4a), the XII line 120, and the line 184 which bears an M signal when the hi-low mode is selected. Therefore, the gate 200 is effective or is operated when the hi-low mode is selected and when there is a coincidence of pulses on the 116b line and the XII line. This occurs for the first time at pulse time 36, and thus at pulse time 36 the gate 200produces a pulse which is passed over a line 202 to one input of an OR gate 204. The output of the OR gate 204 is connected to the J input of a JK flip-flop 206, hereinafter referred to as the W flip-flop.
The W flip-flop, when set, designates a window interval, by producing a high voltage level on its Q output, which is connected by a line 208 to one input of an AND gate 210. The second input of the AND gate 210 is connected to the line 130,which is the serial data output from the multiplexer 128. Accordingly, the output of the gate 210 first occurs in response to the first pulse on the line 130 following setting of the flip-flop 206, and is conveyed over a line 212 to one input of an ANDgate 214 (FIG. 4a). Two other inputs to the AND gate 214 are derived from the M line 184 and the Q output of a JK flip-flop 218 (FIG. 4e), which is hereinafter referred to as the FN flip-flop.
At the time of operation of the AND gate 210, the flip-flop 218 is in its reset condition, so that the potential on its Q output line 220 is high. The line 220 is connected as an input to the AND gate 214. Thus, the first pulse which passes theAND gate 210, providing the M line is high, is effective to enable the AND gate 214, and the fourth input which is connected by a line 106 functions to operate the AND gate 214 at the next inverted clock pulse time, producing an output which is appliedto a set terminal 136 of the A latches 132. In this way the first data pulse appearing on
the line 130 is effective to set the A latches, and the condition of the counters 108 and 114 at this time describes the note and octave location of the operatedswitch of the keyboard responsible for production of the first pulse on the line 130.
The output of the AND gate 210, in addition to supplying a pulse to the AND gate 214, is also connected by a line 222 to the J input of the FN flip-flop 218. The FN flip-flop 218, which was previously in its reset state, is thereby set by suchpulse, representative of the first note encountered following pulse time 36, during a scan of the keyboard. Since the Q output of the FN flip-flop 218 is connected to one input of the AND gate 214, the AND gate 214 is ineffective to supply anyadditional pulses after the first pulse is encountered during the scan.
The Q output of the FN flip-flop 218 is supplied by a line 224 to one input of an AND gate 226 (FIG. 4a). Another input of the AND gate 226 is supplied with inverted clock pulses over the line 106. The other two inputs of the AND gate 226 areconnected to the M line 184, which is high during the hi-low mode, and to the output of the AND gate 210 by way of the line 212. Since the AND gate 210 provides pulses to the lines 212 for each pulse on the line 130 representative of a depressed key,beginning at pulse time 36, a succession of pulses is produced at the output of the AND gate 226, one for each depressed one of the lowest twenty-eight keys of the keyboard. This output is connected through an OR gate 228 to the set terminal 138 of theB latches 134. Accordingly, the B latches 134 are set for each pulse on the line 130, subsequent to the first encountered pulse following pulse time 36, during each scan of the operated keys of the keyboard, and remain set in accordance with the noteand octave of the last key-representative pulse encountered during each cycle of operation of the multiplexer. Pulse time 64 identified the last pulse which can be representative of operation of a key of the keyboard, and an AND gate 230 (FIG. 4d)produces a pulse which resets the W flip-flop 206 at this time, thereby presenting the AND gate 210 from producing any further outputs for setting the B latches 134.
The two inputs of the AND gate 230 are connected to the X3 line and to the ouput of an AND gate 232. The two inputs of the AND gate 232 are connected to the lines 116a and 116c, which enable the AND gate 232 only during the period in which apulse on the X3 line is representative of the pulse time 64. Accordingly, the output of the AND gate 230 is first produced at pulse time 64, so that the W flip-flop 206 is reset at pulse time 64, ending the window period during each cycle of operationduring which the A and B latches 132 and 134 may be set.
2.
