Abstract: A music synthesizer produces pitch-proportional voltages in a novel resistor network, uses these voltage via keyboard control to generate in a voltage-controlled oscillator a high frequency signal, being a multiple of all the harmonic frequencies desired, separates the individual harmonics, converts them to sine waves with voltage-controlled tunable tracking filters, blends the waves in desired proportions, introduces transients of attack, decay, sustain, and release of key into each note, and introduces appropriate vibrato. An alternate apparatus accepts an external signal and converts it to voltages proportional to frequency, whereby accompaniment on pitch, in "close harmony" or more distantly related, is provided.

Abstract: Disclosed is an electronic piano circuit arrangement which combines a multitude of different frequencies within a resistordiode matrix array. The resistor-diode coupling elements provide a different value impedance for various signals to be combined and the amplitude of the signals are predetermined to electronically produce a piano sound which substantially corresponds to the sound of an actual piano tone.

Abstract: The embodiment of the invention disclosed herein is directed to an electronic musical instrument of the keyboard type used to electronically reproduce piano sounds. The circuit has means to vary the amplitude of the piano voice in response to the velocity of the downward movement of the key. Means are provided for producing a fundamental square wave frequency and the second and fourth harmonics thereof, in response to the actuation of a given key on the keyboard. One circuit arrangement includes means for combining the fundamental frequency and the second and fourth harmonics in a predetermined time relation to produce the zero, attack, peak, and decay characteristics of a piano voice as actually produced by a piano string.