Electronic musical instrument

An electronic musical instrument which has a keyboard and produces a musical tone by striking a key of the keyboard, comprising:

• an operation control circuit and an adder both for performing chattering prevent operation processing and touch response detect operation processing of keyboard switches;
• a timing control circuit for controlling the switching between the chattering preventing operation and the touch response detecting operation and the scanning of the keyboard switches to detect their status;
• a musical tone generator which performs a musical tone producing operation asynchronously with the keyboard switch scanning operation and the chattering preventing and touch response detecting operations of the keyboard switches;
• and
• a transfer circuit for transferring touch response information to the musical tone generator;
• wherein the musical tone produced by striking the key of the keyboard has a touch response characteristic corresponding to the key striking force;
• a first switch which is procided for each key and changes its state in response to the striking of the key;
• a second switch which is provided for each key and changes its state with a time lag relative to the first switch;
• a timing circuit for generating a phase signal serving as a reference of a chattering eliminating operation and the touch response detecting operation, a scanning signal, an address signal and a control signal;
• a scan and detect circuit for scanning either one of the first and second switches by the scanning signal from the timing circuit to detect their status;
• a first memory which responds to the control signal from the timing circuit to temporarily store a switch detected signal from the scan and detect circuit;
• a control circuit which responds to the phase signal and the control signal from the timing circuit to perform a predetermined control operation;
• a second memory which responds to the control signal from the timing circuit to temporarily store the output signal of the first memory and a switch status signal having chattering eliminated by the control circuit;
• a third memory which responds to the control signal from the timing circuit to temporarily store the output signal of the second memory and to supply it as first switch information to the control circuit;
• a data bus which time-shares various data signals and various control signals of the entire system;
• a fifth memory which responds to the control signal from the timing circuit to temporarily store the signal on the data bus and to supply it to the control circuit;
• a sixth memory which responds to the control signal and the address signal from the timing circuit to temporarily store the signal on the data bus;
• an adder which performs an add-operation of the output signal of the control circuit to obtain touch response information or chattering prevent information;
• a gate circuit which responds to the control signal from the timing signal to provide the output signal of the adder and the output signal of the control circuit on the data bus;
• a musical tone generator which is supplied with a musical parameter by the signal on the data bus to generate the musical tone;
• and
• a control circuit which controls the musical tone generator and the timing circuit to reflect a touch response characteristic in a musical tone signal.