Abstract: A microprocessor-based processing system for monitoring the tempo rate and rhythm in an electronic musical instrument having an automatic rhythm accompaniment unit. In a first mode of operation, the monitor displays the tempo of the rhythm accompaniment unit in numeric characters representing the number of beats per minute. In a second mode of operation, the monitor displays a numerical 1 representing the down beat in a first display device, a numerical 2 representing the second beat in adjoining display device, and successively incremented numerical integers associated with successive beats in successive numerical display devices until all numerical integers associated with beats have been displayed, thereby producing a timing display having a motion effect for synchronizing the music being played with the rhythm accompaniment tempo.

Abstract: A string chorus generator in an electronic musical instrument that accepts a single audio input signal, applies it to three separate delay lines, and provides delay modulated outputs to be used in producing an ensemble musical effect resembling a group of strings in a string orchestra. Each of the three delay line channels is identical and comprises an analog shift register driven by a high frequency voltage-controlled oscillator along with appropriate filters and buffers. The frequency of the voltage-controlled oscillator of each channel is controlled by the filtered output of a microprocessor, thereby providing precise control over the modulation of each voltage-controlled oscillator. The modulating waveshape is generated by using a lookup table within a microprocessor and comprises a sine wave of 6.25 Hz superimposed on another, larger amplitude, sine wave of 0.78 Hz.

Abstract: Disclosed is a digital arpeggio system for an electronic organ that through the use of digital techniques permits arpeggios, note sequences as well as strum, multi, organ, and normal modes of operation to be played automatically. Two counters scan by counting through an 8.times.8 matrix of 64 words covering the 61 notes of an organ in rapid sequence upon the playing of one or more organ keys. Each word is fed to a corresponding one of 61 decoders, one for each note of the keyboard. If a corresponding key has been played, the decoder provides a signal to a corresponding pulser circuit which enable a corresponding keyer to transmit an audio signal from an audio oscillator corresponding to the played key to an output system and loudspeaker. The two counters are stopped by a clock control while the note is sounded and then the counters are enabled by the counter control to continue counting through the matrix until the next actuated key is located.