Abstract A driving circuit for producing percussion sound employed in an electronic musical instrument is composed of a plurality of circuit branches each of which consists of a capacitor and a resistor connected in parallel, a diode having the conductivity direction coincident with the charging current into the capacitor, and a normally opened switch interlinked with a corresponding key on the keyboard, all connected in series, the number of the circuit branches being substantially equivalent to the number of the keys on the keyboard, all of the plurality of circuit branches being further connected in parallel, one terminal of thus formed parallel circuit being connected with one end of a power source, the other terminal of the parallel circuit being connected through a resistor to the other end of the power source, whereby, when any one of the keys is depressed and the corresponding switch is closed, a charging current flows into the corresponding capacitor and a trigger signal is obtained from the junction point of the capacitor and the resistor connected to the other end of the power source.
In a driving circuit to be used in an electronic musical instrument for obtaining percussion sounds wherein a plurality of branch circuits, each of which includes a capacitor and a switch interlinked with a key on the keyboard of the instrument, are connected in parallel, a first terminal of the thus obtained parallel connected circuit is connected with an end of a power source, a second terminal of said parallel connected circuit is further connected with the other end of said power source through a voltage dividing resistor, and a trigger signal is obtained from a terminal of said voltage-dividing resistor upon depression of a key, the improvement wherein each of said branch circuits comprises a resistor parallely connected with said capacitor, a unidirectonal element and a switching element both connected in series with said parallely connected capacitor and a resistor, whereby a cross current between the branch circuits is eliminated, and the amplitude of the trigger signal is stabilized.
Claim 2
Dependent Claim
160 words
In a driving circuit to be used in an electronic musical instrument for obtaining percussion sounds wherein a plurality of branch circuits, each of which includes a capacitor and a switch interlinked with a key on the keyboard of the instrument, are connected in parallel, a first terminal of the thus obtained parallel connected circuit is connected with an end of a power source, a second terminal of said parallel connected circuit is further connected with the other end of said power source through a voltage dividing resistor, and a trigger signal is obtained from a terminal of said voltage-dividing resistor upon depression of a key, the improvement wherein each of said branch circuits comprises a resistor parallely connected with said capacitor, a unidirectonal element and a switching element both connected in series with said parallely connected capacitor and a resistor, whereby a cross current between the branch circuits is eliminated, and the amplitude of the trigger signal is stabilized.
Claim 3
Dependent Claim
39 words
A driving circuit as defined in claim 1 wherein said unidirectional element is a diode the conductivity direction of which is coincident with the direction of the charging current flowing into the capacitor included in the same circuit branch.
Claim 4
Dependent Claim
19 words
A driving circuit as defined in claim 1 wherein said switching element is a normally opened single-throw, single-pole switch.
Claim 5
Dependent Claim
33 words
A driving circuit as defined in claim 1 wherein said resistor parallely connected with said capacitor is of sufficiently high resistance but producing a time-constant of approximately 50 msec. together with said capacitor.