Abstract: A random access multiport memory includes a plurality of interface ports, a read/write control logic and a random access memory. Each interface port consists of an address bus, a data input/output bus, a read input signal and a write input signal. The read/write control logic consists of a plurality of address decoders, an input control logic and an output control logic. This random access multiport memory provides the capability that each addressable memory location can be directly, independently and randomly read or write by the plurality of ports.

Abstract: A self adaptive and shadow sensitive electronic musical instrument is disclosed. The invention utilizes digital techniques to sense the shadow over any one of the photo cell. There is a reference photo cell's generates a threshold voltage which would be adapted to the ambient light source. Each shaded photo cell generates frequency voltage which will be compared with the reference photo cell's threshold voltage to decide the frequency should be ON or OFF (because the invention uses one bit to represent one photo cell's frequency at 2 MHz sample rate). Then the instrument generates a sound wave shape which is in proportion to the sum of the shaded photo cells' frequency.