Tone generator system for an electronic organ

A frequency dividing circuit for a saw-tooth wave and a staircase wave for use in a tone generator system of an electronic organ wherein said tone generator system includes an original signal source for providing a square wave signal and a saw-tooth or a staircase wave signal, said frequency dividing circuit comprising:

• an inverter circuit;
• square wave frequency divider means having an input terminal for receiving a square wave signal through said inverter circuit, said square wave signal having a repetition period which is the same as that of the original saw-tooth wave signal from said original signal source, said frequency divider means generating frequency divided square wave signals respectively having repetition periods which are even multiples of the repetition period of the input square wave signal;
• means for supplying a constant voltage;
• electronic switching means connected to said square wave frequency divider means and said constant voltage supplying source, said switching means including a plurality of electronic switches which respectively, in response to said frequency divided square wave signals, intermittently pass the constant voltage for providing square wave signals having a constant amplitude;
• and
• combining means connected to said switching means comprising an R-2R ladder network including a series of R resistors having 2R resistor branches connected thereto, one end of the lowest order position of said R-2R ladder network being terminated by a 2R resistor to ground, said lowest order position through a 2R branch resistor thereof being supplies with the original sawtooth wave signal having an amplitude twice as large as that of the input square wave signal, the free ends of other 2R resistor branches at sequentially higher order positions respectively being supplied through said switching means with square wave signals having repetition periods respectively two, four, eight . . . times as large as that of the original saw-tooth wave signal,
• whereby the original saw-tooth signal is combined with the square wave signals each having a period which is an even multiple of that of said original saw-tooth wave signal at the combination ratios of 1, 2, 4 . . . of the square wave signals with respect to the saw-tooth wave signal.

A frequency dividing circuit for a saw-tooth wave and a staircase wave for use in a tone generator system of an electronic organ wherein said tone generator system includes an original signal source for providing a square wave current signal and a saw-tooth or a staircase wave current signal, said frequency dividing circuit comprising:

• square wave frequency divider means having an input terminal to receive the square wave current signal from said original signal source and generating frequency divided square wave signals respectively having repetition periods which are even multiples of the repetition period of the input square wave signal, said input square wave current signal having a repetition period of two times that of said original saw-tooth wave current signal;
• means for supplying a constant current;
• electronic switching means connected to said square wave frequency divider means and said constant current supplying means, said switching means, in response to said frequency divided square wave signals, intermittently passing the constant current for providing square wave current signals having a constant amplitude;
• and
• combining means connected to said switching means comprising an R-2R ladder network composed of a series of L-networks each having an R resistor and a 2R resistor connected at a junction point, one end of said R-2R ladder network at the lowest order position being connected to one switch of said electronic switching means and also being supplied with said original saw-tooth or staircase wave signal, said junction points being connected respectively to corresponding electronic switches for receiving the square wave current signals having repetition periods respectively four, eight, . . . . times as large as that of the original saw-tooth wave signal, whereby the original saw-tooth wave current signal is combined with the square wave current signals each having a period which is an even multiple of that of said original saw-tooth wave current signal at the combination ratios of 1, 2, 4, . . . . of the square wave current signals with respect to the saw-tooth wave current signal.

A frequency dividing circuit for a saw-tooth wave and a staircase wave comprising:

• an original signal source for providing a square wave signal and a saw-tooth or staircase wave signal;
• a plurality of stages of square wave frequency dividers, each having an input terminal to receive said square wave signal from said original signal source and cascaded successively for generating at said stages frequency divided square wave signals respectively having repetition periods which are even multiples of that of the input square wave signal, said input square wave signal having a repetition period of two times that of said original saw-tooth wave signal;
• a reference signal source for supplying a reference signal having a constant magnitude;
• a plurality of electronic switches connected to said plurality of square wave frequency dividers and said reference signal source for intermittently passing said reference signal and thereby respectively introducing square wave signals each having a repetition period of an even multiple of the period of said original saw-tooth wave signal;
• and
• a resistor network having an input terminal to receive said original saw-tooth wave signal or a staircase wave signal from said original signal source, an output terminal to provide a frequency divided saw-tooth wave or staircase wave signal and a plurality of midterminals respectively connected to said plurality of electronic switches for receiving said introduced square wave signals having periods of an even multiple of the period of the original saw-tooth wave signal, said resistor network combining said original saw-tooth wave signal and said introduced square wave signals, the amplitudes of said introduced square wave signals being respectively one time, two times, four times, eight times . . . the amplitude of said original saw-tooth signal.