Voicing system for electronic organ

In a voicing system for an electronic musical instrument including sources of square wave signals having frequencies corresponding to the notes of a musical scale, apparatus for deriving from said square wave signals by operation of playing keys first and second other pulse signals of different wave shapes, both differing from a square wave, and each useful for the production of selected different voice signals, said apparatus comprising, in combination:

• a plurality of player-operated keyswitches,
• means including gating means connected to a source of square wave signals for producing in response to actuation of a keyswitch a first other pulse signal of frequency corresponding to the actuated keyswitch,
• means including a plurality of bus-bars each for gathering the first other pulse signals of frequencies corresponding to a selected multiplicity of notes,
• a plurality of integrating circuit means equal in number to the number of bus-bars connected one each to receive the first other pulse signals gathered at a different one of said bus-bars and operative to convert said first other pulse signals to second other pulse signals having a different waveform suitable for producing a first class of voice signals, each of said integrating circuit means being operative to produce substantially a 6 dB per octave filtering effect throughout the range of frequencies of the first other pulse signals applied thereto and to shift the phase of all harmonics of interest contained therein by substantially 90.degree. in one direction,
• a first mixing amplifier having input and output terminals,
• means for coupling all of said integrating circuit means to the input terminal of said first mixing amplifier whereby to produce at its output terminal second other pulse signals of frequency corresponding to the played notes,
• a second mixing amplifier having input and output terminals, and
• a like plurality of differentiating circuit means, one connected between each of said integrating circuit means and the input terminal of said second mixing amplifier, each of said differentiating circuit means including a capacitor having an impedance value so as to produce substantially a 6 dB per octave filtering effect throughout the range of frequencies of the second other pulse signals applied thereto and to shift the phase of all harmonics of interest contained therein by substantially 90.degree. in the opposite direction, whereby to produce at the output terminal of said second mixing amplifier pulse signals having a waveform differing from the waveform of said second other pulse signals for producing a second different class of voice signals.

In a voicing system for an electronic musical instrument, the combination comprising:

• means for producing first and second pulse signals of the same frequency but different wave shapes, each of which contains both even and odd harmonics and wherein partials of interest contained in said first pulse signals are displaced by substantially 90.degree. with respect to corresponding partials contained in said second pulse signals,
• a first filter network connected to receive said first pulse signal and operative to modify the same to produce at its output a first voice signal, said first filter network being operative to shift the phase of at least some partials of an applied first pulse signal by about 90.degree.,
• a second filter network connected to receive said second pulse signal and operative to modify the same to produce at its output a second different voice signal, said second filter network producing no phase shift to an applied second pulse signal,
• a mixing amplifier having inverting and noninverting input terminals and an output terminal,
• means for coupling the output signal from said first filter network to the inverting input terminal of said mixing amplifier, and
• means for coupling the output signal from said second filter network to the noninverting input terminal of said mixing amplifier,
• whereby to minimize cancellation of corresponding partials of the output signals derived from said first and second filter networks when sounded simultaneously.

In a voicing system for an electronic musical instrument including sources of square wave signals having frequencies corresponding to the notes of a musical scale, apparatus for deriving from said square wave signals by operation of playing keys first and second other pulse signals of different wave shapes, both differing from a square wave, said apparatus comprising, in combination,

• a plurality of player-operated keys,
• means including a like plurality of gating means connected to said soruces of square wave signals for producing in response to actuation of a keyswitch a first other pulse signal of frequency corresponding to the activated keyswitch, said gating means each comprising,
• switching means operative to be closed and opened in response to the upper and lower levels, respectively, of a square wave signal from one of said sources,
• a source of direct current potential,
• a keyswitch and an RC time constant circuit, including a first resistor and a first capacitor, connected between said source of direct current potential and a circuit junction point,
• a second capacitor connected between said circuit junction point and a point of reference potential arranged to be charged from said source of direct current potential when said switching means is open, and
• a diode connected between said circuit junction point and said switching means arranged to discharge said second capacitor when said switching means is closed,
• whereby to produce at said circuit junction point a first other pulse signal differing from a square wave and containing both odd and even harmonics and of a frequency corresponding to the actuated keyswitch,
• means including a plurality of bus-bars for gathering the first other pulse signals produced at said circuit junction point of frequencies corresponding to a multiplicity of notes,
• a plurality of integrating circuit means, equal in number to the number of bus-bars, connected one each to receive the first other pulse signals gathered at a different one of bus-bars and operative to convert said first other pulse signals to second other pulse signals having a substantially sawtooth waveform, each of said integrating circuit means being operative to produce substantially a 6dB per octave filtering effect throughout the range of frequencies of the first other pulse signals applied thereto and to shift the phase of all harmonics of interest contained therein by substantially 90.degree.,
• a first mixing amplifier having input and output terminals,
• means for connecting all of the integrating circuit means to the input of said first mixing amplifier whereby to produce at its output terminal second other pulse signals of frequency corresponding to played notes,
• means including at least one additional bus-bar for gathering the first other pulse signals produced at said circuit junction point of all of said plurality of gating means of frequency corresponding to played notes,
• a second mixing amplifier having input and output terminals, and
• means for connecting said at least one additional bus-bar to the input terminal of said second mixing amplifier whereby to produce at its output terminal first other pulse signals of frequencies corresponding to played notes.

In an electronic musical instrument including sources of square wave signals having frequencies corresponding to the notes of a musical scale, a gating circuit for deriving from said square wave signals by operation of playing keys pulse signals of a wave shape differing from a square wave which contain both even and odd harmonics, said gating circuit comprising in combination:

• electronic switch means connected to receive said square wave signal and operative to be closed and opened in response to the upper and lower levels, respectively, of said square wave signal,
• a source of direct current potential,
• a keyswitch and an RC time constant circuit, including a first resistor and a first capacitor, connected in series in that order beween said source of direct current potential and a circuit junction point,
• a second capacitor connected between said circuit junction point and a point of reference potential arranged to be charged at a predetermined rate from said source of direct current potential when said electronic switch means is open, and
• means including a diode connected between said circuit junction point and said electronic switch means arranged to discharge said second capacitor when said electronic switch means is closed,
• whereby to produce at a said circuit junction point a pulse signal differing from a sqare wave and containing both even and odd harmonics and of a frequency corresponding to the frequency of said square wave signal.

In a voicing system for an electronic musical instrument, the combination comprising:

• a source of complex wave signal,
• a plurality of different filter networks each connected to receive and operative to modify the relative amplitudes of the various partial frequencies of said complex wave signal to produce a respective output signal representative of a distinctive organ voice, at least some of said filter networks, incidental to their filtering action, causing differing phase shifts of the fundamental and harmonic frequencies of the applied complex wave signal,
• a mixing amplifier having inverting and noninverting input terminals and an output terminal,
• means connected to the output terminal of said mixing amplifier for transducing signals produced thereat into sound,
• means for coupling the output signal from selected one or more of said filter networks to the noninverting input terminal of said mixing amplifier, and
• means for coupling the output signal from such other one or more of said filter networks to the inverting input terminal of said mixing amplifier as will maximize addition at the output terminals of said mixing amplifier of the stronger partials of the individual organ voice signals when two or more are sounded simultaneously.