Electronic percussion instrument - has resonant circuit which simulates different instruments according to resonant frequency and decay time

摘要

The electronic circuit produces a sound simulating a percussion instrument, giving a damped oscillation with decay determined by the combination of a parallel resonance circuit and an output impedance. By variation in the resonant frequency and the decay time a variety of instruments can be imitated. A DC voltage is applied between a terminal (Vb) and earth across which are connected a self-inductance (L), a condenser (C) and an actuating switch (S). A resistance (R) bridges the condenser. A bank of units can be connected each via an individual switch to a common earth busbar. With the switch open, the condenser discharges through the resistance. On closing the switch (keying the instrument) the condenser is charged through the inductance, the two together acting as a parallel resonant circuit completed through the low impedance of the power source.