Abstract: A circuit for producing a special effect, such as a sliding tone effect or a "Hawaiian Guitar" tonal effect, utilizes a coincidence gating circuit and a bi-stable flip-flop to control a time delay circuit connected to the tone generating circuit of an electronic organ. This circuit responds to the playing of two keys of the keyboard in a rolled chord fashion to cause an automatic detuning of the master oscillator of the tone generating circuit, so that the tones go one semi-tone flat for a short period of time and then glide back into proper tune as controlled by the characteristics of the time delay circuit.

Abstract: An electronic musical instrument employing top octave synthesizer circuits (TOS circuits) for generating the musical tones to be reproduced by the instrument employs a single master oscillator common to all of the top octave synthesizer circuits for supplying the trains of clock pulses to the synthesizer circuits for their operation. To prevent phase-locked conditions from existing in the frequencies produced by different synthesizers, the clock pulses from the master oscillator are supplied to the synthesizers through coincidence gate logic circuitry which is controlled by means of a low frequency oscillator and a divider or shift register circuit to delete different ones of the clock pulses from the clock pulse signal trains for each of the different synthesizers. This causes all of the frequencies obtained from the synthesizers to be slightly different from one another, independent, and not phase-locked.

Abstract: An electronic organ uses several top octave synthesizer circuits for producing the various tones used in the organ. Each of the top octave synthesizers is capable of producing any tone which can be produced by the organ. As a consequence, the outputs of each synthesizer are applied to a coupler circuit, which in turn is connected to an octave assignment switching tree for directing the tones coupled to the inputs of the switching tree to individual leads, each corresponding to a different octave in the range of tones produced by the organ. The similar octave leads from each of the different octave switching circuits are connected together to common flute octave buses, so that the filters connected to the output buses have substantially fewer tones appearing at the input than one which would have the full tone range of the organ. Typically, the range of tones appearing at a filter input is one octave or less.