Musical tone synthesizing apparatus capable of changing musical parameters in real-time

A musical tone synthesizing apparatus comprising:

• a first memory for storing a first procedure of instructions which is completely performed in a predetermined period;
• a second memory for storing a second procedure of instructions which is completely performed during a plurality of predetermined periods, said instructions belonging to said second procedure being allocated to groups respectively so that each group of instructions is performed in each of said plurality of predetermined periods;
• and
• a processing means for performing a first kind of arithmetical operations in accordance with said first procedure of instructions, said first kind of arithmetical operations being repeatedly performed in each predetermined period, said processing means also performing a second kind of arithmetical operations in accordance with said second procedure of instructions, said second kind of arithmetical operations being completely performed during said plurality of predetermined periods, said first kind of arithmetical operations and a part of said second kind of arithmetical operations being performed in a time-division manner in each predetermined period,
• whereby said processing means eventually creates tone data in each predetermined period on the basis of results of said arithmetical operations, wherein said tone data represents a musical tone to be synthesized.