Electronic tone-generating system

A tone-generating system for an electronic keyboard musical instrument wherein an audible tone closely approximating the corresonding tone of a conventional keyboard instrument is generated electronically in response to the depression and subsequent release of a key by the player of the instrument, with said tone having a predetermined frequency spectrum and an envelope characteristic which varies in accordance with the intensity with which the key is depressed, said system comprising:

• keying transducer means including a two-position electrical switch and a manually actuable key coupled to said switch for placing said switch in one position upon depression of said key and in the other position upon release of said key, said key being normally in released position and said switch developing a keying signal having a first value when said key is released, a second value when said key is depressed, and a third value when said key is between the released and depressed positions;
• tri-level sensing means coupled to said switch and responsive to said keying signal for sensing which state said switch is in and developing a corresponding counter control sighal;
• transition time counter means coupled to said sensing means and responsive to said counter control signal for counting the time that elapses when said key is moved from the released position to the depressed position and developing a corresponding transition time signal;
• amplitude scaling read-only memory means having a predetermined plurality of digital amplitude scaling characteristics stored therein, coupled to said transition time counter means and responsive to said transition time signal for developing a digital amplitude scaling signal corresponding to the intensity with which said key is depressed;
• variable rate clock means for generating a timing signal having a rate which is capable of being varied in response to an external control signal;
• envelope control counter means coupled to said variable rate clock means and responsive to said timing signal for generating an envelope control signal;
• tonal envelope memory means having a predetermined digitized representation of a tonal wave envelope stored therein and capable of being read out incrementally, coupled to said envelope control counter means and responsive to said envelope control signal for generating a digital envelope signal;
• oscillator means coupled to said keying transducer means and responsive to the actuation of said key to said depressed position for generating an oscillatory electrical signal having said predetermined frequency spectrum;
• converter means coupled to said amplitude scaling read-only memory means and to said tonal envelope memory means to form a composite analog signal;
• output gating means coupled to said oscillator means and to said converter means for modulating said oscillatory signal with said composite analog signal to produce an electrical signal representative of said initiated tone;
• and an electrochemical transducer coupled to said output means and responsive to said electrical signal for converting said composite electrical signal into an audible tone.

A tone-generating system for an electronic musical instrument of the percussion type wherein a plurality of audible tones are generated electronically in response to the manual actuation of the system by the player of the instrument, with each said tone having a predetermined frequency spectrum and an envelope characteristic which varies in accordance with the intensity of the manual actuation by which the player of the instrument actuates the tone, and with various ones of said tones being assigned to predetermined tonal groups, said system comprising:

• a plurality of manually actuable means for initiating generation of said tones;
• a corresponding plurality of detector means coupled to said tone initiating means and responsive to the actuation of said tone initiating means for developing control signals indicative of the intensity with which the tone initiating means is manually actuated for each said tone initiated;
• means coupled to said detector means and responsive to said control signals for generating a digital scaling signal representative of the variations in amplitude of said initiated tones with respect to the intensity with which said tone initiating means is actuated for each said tone initiated;
• oscillator means coupled to said tone initiating means and responsive to the actuation of said tone initiating means for generating an oscillatory signal having said predetermined frequency spectrum for each said tone initiated;
• clock means for generating timing signals;
• a plurality of multiplexing means respectively associated with said tonal groups and each coupled to the digital scaling signal generating means for its associated tonal group and responsive to said timing signals for generating multiplexed digital scaling signal for each said tonal group;
• means coupled to said clock means and responsive to said timing signals for generating a digital envelope signal for each said tone initiated;
• a plurality of converter means respectively coupled to said plurality of multiplexing means and to said digital envelope signal generating means to form a composite analog signal for each said tonal group;
• a plurality of output means each coupled to said oscillator means and to said converter means for separating and smoothing the envelope signals in the tonal groups and for modulating said oscillatory signal with said separated signls to produce electrical signals representative of said initiated tones;
• and means, including a summing amplifier and an electromechanical transducer, coupled to said output means for combining said electrical signals and converting said combined electrical signals into audible tones.

A tone-generating system for an electronic keyboard musical instrument wherein a pluralty of audible tones closely approximating the corresponding tones of a conventional keyboard instrument are each generated electronically in response to the depression and subsequent release of a corresponding key by the player of the instrument, with each said tone having a predetermined frequency spectrum and an envelope characteristic which varies in accordance with the intensity with which the corresponding key is depressed, and with various ones of said tones being assigned to predetermined tonal groups, said system comprising;

• keying transducer means including a plurality of two-position electrical switches and a corresponding plurality of manually actuable keys respectively coupled to said switches for individually placing said switches in one position upon depression of the corresponding key and in the other position upon release of the corresponding key, each said key being normally in its released position and each said switch developing a keying signal having a first value when said key is released, a second value when said key is depressed, and a third value when said key is between the released and depressed positions;
• an associated plurality of tri-level sensing means respectively coupled to said switches and respectively responsive to said keying signals for sensing which state each said switch is in and developing a corresponding plurality of counter control signals;
• a corresponding plurality of transition time counter means respectively coupled to said tri-level sensing means and respectively responsive to said counter control signals for individually counting the time that elapses when each said key is moved from the released position to the depressed position and developing corresponding transition time signals;
• means for generating multiplexer timing signals;
• a plurality of multiplexing means respectively associated with said tonal groups and each coupled to said transition time counter means for its associated tonal group and responsive to said multiplexer timing signals for generating a multiplexed transition time signal;
• a plurality of amplitude scaling read-only memory means each corresponding to a different one of said tonal groups and each having a predetermined plurality of digital amplitude scaling characteristics stored therein, said memory means coupled to said multiplexing means and responsive to said multiplexed transition time signals for developing a plurality of multiplexed digital amplitude scaling signals each corresponding to the intensity with which its associated key is depressed;
• variable rate clock means for generating a plurality of envelope control counter timing signals each having a rate which is capable of being varied in response to an external control signal;
• a plurality of envelope control counter means corresponding to said tonal groups and each coupled to said variable rate clock means and respectively responsive to said envelope control counter timing signals for generating an envelope control signal for its associated tone;
• a plurality of tonal envelope memory means corresponding to said tonal groups and each having a predetermined digitized representation of a tonal wave envelope stored therein and capable of being read out incrementally and each respectively coupled to said envelope control counter means and respectively responsive to said envelope control signals for generating a corresponding digital envelope signal for each said tone initiated;
• oscillator means coupled to said keying transducer means and responsive to the actuation of said keys to said depressed position for generating an oscillatory electrical signal having said predetermined frequency spectrum for each said tone initiated;
• a plurality of converter means corresponding to said tonal groups and respectively coupled to said amplitude scaling memory means and to said tonal envelope memory means to form a composite analog signal for each tonal group;
• a plurality of output gating means for seperating the tone envelopes in the tonal groups and means coupled to said oscillator means and to said converter means for modulating said oscillatory signals with said separated analog signals to produce electrical signals representative of said initiated tones;
• and means, including a summing amplifier and an electromechanical transducer, coupled to said output means for combining said electrical signals and converting said combined electrical signals into audible tones.

A tone-generating system for an electronic musical instrument of the percussion type wherein a plurality of audible tones are generated electronically in response to the manual actuation of the system by the player of the instrument, with each said tone having a predetermind frequency spectrum and an envelope characteristic which varies in accordance with the intensity of the manual actuation by which the player of the instrument actuates the tone, said system comprising:

• a plurality of manually actuable means for initiating generation of said tones;
• timing means for generating multiplexing signals;
• multiplexing means, including an output terminal, coupled to said plurality of tone initiating means and responsive to said multiplexing signals for addressing each said tone initiating means individually and providing a corresponding serial output signal at said output terminal;
• detector means including a demultiplexer, coupled to said output terminal and responsive to said serial output signal for developing a control signal indicative of the intensity with which each said tone initiating means is manually actuated;
• means coupled to said detector means and responsive to said control signal for generating a digital scaling signal representative of the variations in amplitude of said initiated tones with respect to the intensity with which said tone initiating means is actuated for each said tone initiated;
• oscillator means coupled to said tone initiating means and responsive to the actuation of said tone initiating means for generating an oscillatory signal having said predetermined frequency spectrum for each said tone initiated;
• clock means for generating timing signals;
• means coupled to said clock means and responsive to said timing signals for generating a digital envelope signal for each said tone initiated;
• converter means coupled to said digital scaling signal generating means and to said digital envelope signal generating means to form a composite analog signal;
• output means for separating said composite analog signal into individual tone analog signals and means coupled to said oscillator means for modulating said oscillatory signals with said tone analog signals to produce electrical signals representative of said initiated tones;
• and an electromechanical transducer coupled to said output means and responsive to said electrical signals for converting said electrical signals into audible tones.

A tone-generating system for an electronic keyboard musical instrument wherein a plurality of audible tones closely approximating the corresponding tone of a conventional keyboard instrument are each generated electronically in response to the depression and subsequent release of a corresponding key by the player of the instrument, with each said tone having a predetermined frequency spectrum and an envelope characteristic which varies in accordance with the intensity with which the corresponding key is depressed, said system comprising:

• keying transducer means including a plurality of two-position electrical switches and a corresponding plurality of manually actuable keys respectively coupled to said switches for individually placing said switches in one position upon depression of the corresonding key and in the other position upon release of the corresponding key, each said key being normally spring-biased to its released position and each said switch developing a keying signal having a first value when said key is released, a second value when said key is depressed, and a third value when said key is between the released and depressed positions;
• timing means for generating multiplex signals;
• multiplexing means, including an output terminal, coupled to said keying transducer means and responsive to said multiplexing signals for addressing each said switch individually and providing a corresponding serial keying signal at said output terminal;
• tri-level sensing means including a demultiplexer, coupled to said two position electrical switches and responsive to said serial keying signal for sensing which state each said switch is in and deveoping a corresponding counter control signal for each said tone initiated;
• a plurality of transition time counter means coupled to said sensing means and respectively resonsive to said counter control signal for individually counting the time that elapses when each said key is moved from the released position to the depressed position and developing corresponding transition time signals;
• a plurality of amplitude scaling read-only memory means each having a predetermined plurality of digital amplitude scaling characteristics stored therein, coupled to said transition time counter means and respectively responsive to said transition time signals for developing a digital amplitude scaling signal corresponding to the intensity with which said key is depressed for each said tone initiated;
• variable rate clock means for generating a plurality of envelope control couner timing signals each having a rate which is capable of being varied in response to an external control signal;
• a plurality of envelope control counter means coupled to said variable rate clock means and respectively responsive to said timing signals for generating an envelope control signal for each said tone initiated;
• a plurality of tonal envelope memory means each having a predetermined digitized representation of a tonal wave envelope stored therein and capable of being read out incrementally and each respectively coupled to said envelope control counter means and respectively responsive to said envelope control signals for generating a corresponding digital envelope signal for each said tone initiated;
• oscillator means coupled to said keying transducer means and responsive to the actuation of said keys to said depressed position for oscillatory electrical signal having said predetermined frequency spectrum for each said tone initiated;
• a plurality of converter means respectively coupled to said amplitude scaling read-only memory means and to said tonal envelope memory means to form a composite converter output signal;
• a plurality of output gating means coupled to said converter output signal for separating said signal into individual tone analog signals and coupling into said oscillator means for modulating said oscillatory signals to produce electrical signals representative of said initiated tones;
• and an electromechanical transducer coupled to said output means and responsive to said electrical signals for converting said composite electrical signals into audible tones.