Digital touch response circuit of electronic musical instrument

Abstract

In a digital touch response circuit or touch signal processing circuit for producing a control waveform signal to control a musical tone to be produced in response to a player's finger touch on a key, digital touch data representing a player's instantaneous finger touch on a key is compared in a comparison circuit with digital output data from an operation circuit such as an adder circuit, which varies at a rate as the result of addition of a rate value to input data applied to the adder. A selection circuit is responsive to the comparison circuit to selectively couple the output data of the adder and the digital touch data to a temporary memory circuit such as shift registers. The output data from the memory circuit is coupled to the adder as the input data thereto. When the pressure applied to the key is increasing (crescendo) the digital touch data is fed to the memory through the selection circuit, and, when the pressure applied to the key is decreasing (diminuendo) at a rate larger than the rate at which the output data of adder varies, the output data of the adder is coupled to the memory circuit via the selection circuit to thereby obtain a decaying control waveform signal. The output data of the memory is utilized to form the control envelope.