Digital tone and chord generators

摘要

An electronic organ includes a read-only memory which stores eight bit binary words each having a digital value proportional to the frequency of a different note. When a chord keyswitch is actuated, a corresponding chord selector controlled by a multiplexer circuit causes the randomly addressable memory to sequentially generate binary words corresponding to the frequencies of the notes forming the selected chord. Each binary word is stored in a latch associated with a different universal tone generator capable of generating any tone as controlled by the stored binary word. Each universal tone generator includes a comparator which recognizes a match between the associated latch and a counter which receives clock pulses from a single fixed frequency oscillator. The comparator resets the counter and generates an output pulse which is divided to form an audible tone signal.