Abstract: A method and apparatus is described for selectively adjusting control signal timing in a memory device as a function of the externally applied system clock speed. The memory device includes clock sensing circuitry that receives the system clock signal and responsively produces a speed signal having a value corresponding to the frequency of the system clock signal. The clock sensing circuitry includes a plurality of series-connected time-delay circuits through which a signal derived from the system clock signal propagates. The clock sensing circuitry also includes a plurality of latch circuits, each coupled with a respective one of the time delay circuits and latching the value of the signal reaching the respective time delay circuit. The speed signal is then derived from these latched signal values, indicating through how many of the time-delay circuits the signal has propagated.

Abstract: Disclosed is an electronic musical instrument comprised of operators organized in repeating patterns of seven. The operators are electronically interpreted to correspond only to the valid notes of a selected scale. The repeating patterns of seven notes directly corresponds to the vast majority of mucis theory and thus constitutes an enormous simplification in the art of learning, performing and composing music. The present invention enables users of the electronic musical instrument to master chord and note progressions in any scale and mode by learning only a single set of note patterns, in contrast to the myriad scales, chord and note patterns which must be learned on traditional keyboard and pedal devices.