Electronic musical instrument keying system with envelope sample memorizing voltage dividers

Claim 2

A keying system for use with an electronic musical instrument comprising: a key-operated switch; an input terminal to receive a tone signal to be keyed; a sequentially changing-over voltage divider network includinG a circuit ground, a common input resistor having one end connected with said input terminal and another end defining an output line, a bank of resistor elements connected with the output line and respectively having values predetermined to represent the respective amplitudes as sampled values of an intended decaying envelope of the tone signal with time axis for individually constituting voltage dividers together with the common input resistor, and also including first switching elements respectively connected in series with said resistor elements individually to the ground and each having a control electrode, and a short-circuiting switching element connecting said output line to ground having a control electrode for grounding said output line when a given voltage is applied to said control electrode of said short-circuiting switching means, and a reference divider resistor being connected between the output line and the ground; an output terminal connected to the output line for deriving a keyed tone signal; an n-scale counter with successive n-output ends connected to the respective control electrodes of the switching elements for sequentially supplying a pulse to said first switching elements so as to render said switching elements conductive sequentially; a counter drive circuit for producing clock pulses; and gate means connected between said counter drive circuit and said n-scale counter and to said key-operated switch for controlling the flow of the clock pulses to said counter in response to the operation of said key-operated switch.

Claim 3

A keying system according to claim 1, in which said gate means includes a flip-flop having a set input terminal responsive to the movement of the key-operated switch to detect the beginning of the depression of the corresponding key and to store a binary signal representing the condition of the key depression, a gate circuit responsive to said stored signal for allowing the flow of the clock pulses toward the n-scale counter, and a connection between the output of said flip-flop and said short-circuiting switching element which is rendered inoperative in the presence of said binary signal.

Claim 4

A keying system according to claim 2, in which said gate circuit has first and second input terminals connected to said clock pulse producing circuit and the output of said flip-flop circuit, respectively, and a third input terminal connected to the set input terminal of said flip-flop, whereby said gate circuit is still kept closed even upon detecting the depression of the key and is enabled upon detecting the beginning of the release of the depressed key.

Claim 5

A keying system for an electronic musical instrument having a plurality of tone signal sources covering musical range of several octaves, a common output system, and a plurality of keyers individually connecting the sources to the output system, said keyers individually integrally comprising: a bank of change-over controlled voltage divider circuits in series connected between each source and the output system, said voltage divider circuits including an input terminal, a common input resistor connected to said input terminal, a common output resistor having one end connected in series to the opposite end of said input resistor and the other end grounded, an output terminal connected at the junction between said input and output resistors, a bank of resistors and normally-nonconducting voltage-controlled switching elements individually in series thereto, which are in parallel connected across said output resistor, and a common normally conducting voltage-controlled switching element in parallel connected across said output resistor, said bank of the resistors successively being predetermined in value in correspondence to the decay amplitudes of a required pattern in the keyer; an n-scale counter having a zero setting terminal and n-1 output setting terminals individually connected with said bank of the switching elements For successively supplying control pulses thereto, the number of which corresponds to that of said bank of switching elements; a clock pulse generator for generating clock pulses to drive said n-scale counter; gate means having an input and provided between said clock pulse generator and said n-scale counter to couple said clock pulses to said counter when an enabling signal is applied to said input; and actuating means for applying a keying control voltage to said common switching element and an enabling signal to said gate means and including a playing key-operated switch, a DC potential source connected to said switch, so as to generate a keying control voltage when said switch is operated, and a binary memory connected to said key-operated switch and to said gate means for changeably storing the keying control voltage which is generated when said key-operated switch is operated, and providing an output as a function of the stored voltage, said output being supplied to said input of said gate means to enable said gate means.

Claim 6

A keying system for an electronic musical instrument having a plurality of tone signal sources covering musical range of several octaves, a common output system, and a plurality of keyers individually connecting the sources to the output system, said keyers individually integrally comprising: a bank of change-over controlled voltage divider circuits in series connected between each source and the output system, said voltage divider circuits including an input terminal, a common input resistor connected to said input terminal, a common output resistor having one end connected in series to the opposite end of said input resistor and the other end grounded, an output terminal connected at the junction between said input and output resistors, a bank of resistors and normally-nonconducting voltage-controlled switching elements individually in series thereto, which are in parallel connected across said output resistor, and a common normally conducting voltage-controlled switching element in parallel connected across said output resistor, said bank of the resistors successively being predetermined in value in correspondence to the decay amplitudes of a required pattern in the keyer; an n-scale counter having a zero setting terminal and n-1 output setting terminals individually connected with said bank of the switching elements For successively supplying control pulses thereto, the number of which corresponds to that of said bank of switching elements; a clock pulse generator for generating clock pulses to drive said n-scale counter; gate means having an input and provided between said clock pulse generator and said n-scale counter to couple said clock pulses to said counter when an enabling signal is applied to said input; and actuating means for applying a keying control voltage to said common switching element and an enabling signal to said gate means and including a playing key-operated switch, a DC potential source connected to said switch, so as to generate a keying control voltage when said switch is operated, and a binary memory connected to said key-operated switch and to said gate means for changeably storing the keying control voltage which is generated when said key-operated switch is operated, and providing an output as a function of the stored voltage, said output being supplied to said input of said gate means to enable said gate means.

Claim 7

The keying system according to claim 4, in which said actuating means generates the keying control voltage when said playing key switch begins to be depressed, thereby providing percussive effects to the keyed tone signal.

Claim 8

The keying system according to claim 4, in which said actuating means and said gate means are connected so that said enabling signal is supplied to said gate means only when the depressed key is released, whereby the keyed tone signal has a fixed amplitude waveform for the period during which the key is depressed, while the keyed tone signal has a decay amplitude waveform once the depressed key is released.

Claim 9

The keying system according to claim 4, in which said gate means is a two-input AND circuit receiving the clock pulses from the clock pulse generator and the output of said binary memory, respectively.

Claim 10

The keying system according to claim 6, in which said gate means is a three-input AND circuit adapted to receive the clock pulses from the clock generator, the keying control voltage and the output of the memory, respectively.

Claim 11

The keying system according to claim 4, in which said bank of voltage divider circuits includes a plurality of sets of resistors as said bank of resistors, each set of resistors being sequentially preset in values so as to have different amplitude pattern, and voltage-controlled switching elements in series to said sets of individual resistors between them and said bank of switching elements, and an amplitude pattern selector switch for selectively applying a DC voltage to the selected switching elements corresponding to the selected one of said sets of resistors.

Claim 12

The keying system according to claim 4, in which a reset means is provided to reset the n-scale counter each time the keying control voltage is generated.

Claim 13

An integrable touch-responsive tone keyer circuit for an electronic musical instrument comprising a first and a second voltage divider network each having a bank of resistors and semi-conductor switching elements individually in series connected thereto, the values of the bank of resistors being successively preset in conformity with the characteristic amplitudes of a required pattern, said first divider network having a common input resistor for receiving a tone signal to be keyed, and connected in series with the bank of resistors thereof the junction of which is connected to the bank of resistors of said second divider network and constitutes an output end of the keyer; a first and a second serial counters provided to said first and second divider networks respectively each for sequentially providing pulse outputs to the respective switching elements so as to successively constitute divider circuits by the bank of resistors; a first and a second clock pulse generators provided individually for said first and a second counters for generating clock pulses thereby to drive said counters respectively; a first and a second keying control circuit connected to a playing key-operated switch, means connecting said switch to an actuating potential, each of said control circuits including a memory connected to said key-operated switch, for shifting from a first to second output condition when said switch is operated to apply said actuating potential to said memory, gate circuits connected between the clock generators and the counters and to said memorys for coupling said clock generators to said counters so that said counters are driven by said pulses, and reset means for the memory and the counter being connected thereto, said first control circuit controlling the flow of the clock pulses produced from the first clock generator to said first counter in accordance with the depression speed of the key to thereby determine the level of the received tone signal by setting one of the first divider networks and said second control circuit controlling the flow of clock pulses from said second clock generator to said second counter once the depressed key is released to thereby determine the decay characteristics of the second divider network.

Claim 14

An integrable touch-responsive tone keyer circuit for an electronic musical instrument comprising a first and a second voltage divider network each having a bank of resistors and semi-conductor switching elements individually in series connected thereto, the values of the bank of resistors being successively preset in conformity with the characteristic amplitudes of a required pattern, said first divider network having a common input resistor for receiving a tone signal to be keyed, and connected in series with the bank of resistors thereof the junction of which is connected to the bank of resistors of said second divider network and constitutes an output end of the keyer; a first and a second serial counters provided to said first and second divider networks respectively each for sequentially providing pulse outputs to the respective switching elements so as to successively constitute divider circuits by the bank of resistors; a first and a second clock pulse generators provided individually for said first and a second counters for generating clock pulses thereby to drive said counters respectively; a first and a second keying control circuit connected to a playing key-operated switch, means connecting said switch to an actuating potential, each of said control circuits including a memory connected to said key-operated switch, for shifting from a first to second output condition when said switch is operated to apply said actuating potential to said memory, gate circuits connected between the clock generators and the counters and to said memorys for coupling said clock generators to said counters so that said counters are driven by said pulses, and reset means for the memory and the counter being connected thereto, said first control circuit controlling the flow of the clock pulses produced from the first clock generator to said first counter in accordance with the depression speed of the key to thereby determine the level of the received tone signal by setting one of the first divider networks and said second control circuit controlling the flow of clock pulses from said second clock generator to said second counter once the depressed key is released to thereby determine the decay characteristics of the second divider network.

Claim 15

The touch-responsive tone keyer circuit according to claim 11, in which each of said voltage divider networks includes a plurality of sets of resistors as said bank of resistors, each set of resistors being sequentially preset in value so as to have a different amplitude pattern, and voltage-controlled switching elements in series to said sets of individual resistors between them and said bank of switching elements, and an amplitude pattern selector switch for selectively applying a DC voltage to selected switching elements corresponding to a selected one of said sets of resistors.

Claim 16

The touch-responsive tone keyer circuit according to claim 11 in which said first and said second clock pulse generators are of the variable frequency type.

Claim 17

The keying system according to claim 4, in which the frequency of the clock pulse generator is variable.

Claim 18

The keying system according to claim 4, in which said switching elements are constituted by FET''s.

Claim 19

The keying system according to claim 4, in which said binary memory of the actuating means is constituted by a flip-flop circuit.

Claim 20

The touch-responsive tone keyer circuit according to claim 11, in which said switching elements are constituted by FET''s.