Abstract: An electronic musical instrument of the digital synthesis type that uses digital processing techniques to impart not only the desired harmonic structure and pitch, but also to impart the correct amplitude and envelope. Only after all of the harmonic structure processing, all amplitude scaling, and all panning/mixing has been performed in digital circuitry, are the four outputs converted by digital to analog converters into analog musical outputs. Part of the digital processing includes a digital scaling circuit using a barrel interpolator to scale each sample from 1/2 to 31/32 and a shift right register to scale each sample between 1 and 1/32,768.

Abstract: A digital synthesizer type electronic musical instrument that has the ability to automatically accompany a pre-recorded song with appropriate chords. The pre-recorded song is transposed into the key of C major, divided into a number of musical sequences, and then stored in a data structure. By analyzing the data structure of each musical sequence, the electronic musical instrument also can provide intelligent accompaniment, such as voice leading, to the notes that the operator plays on the keyboard.