Method and apparatus for generating tone signals for a musical instrument

In an electronic organ having playing keys and keyers actuated by the keys, electroacoustic means connected to receive tone signals from the keyers, and means for generating tone signals for suppling to the keyers;

• said means comprising a stable high frequency oscillator, a plurality of variable frequency divider means having an input connected to said oscillator, a phase detector for each divider means having one input connected to the output of the respective divider means, a voltage controlled oscillator connected to the output of each phase detector, a synthesizer having an input connected to the output of each voltage controlled oscillator and each having a plurality of outputs at respective frequencies, means connecting an output of each synthesizer to the other input of the respective phase detector, means for adjusting said divider means to predetermined respective division ratios, and circuit means including signal mixing means connecting the outputs of said synthesizers to said keyers to supply tone signals thereto.

The method of generating at least one desired range of tone signals which have respective frequencies differing fractionally from the frequencies of respective ones of a selected range of musical tone signals which comprises;

• supplying a stable high frequency which is equal to the frequency of the highest tone of said selected range of musical tone signals multiplied by a large first number, dividing the thus supplied high frequency by at least one second number differing from said first number by a fractional part of the first number and supplying a thus derived divided down frequency to one input of a phase lock loop, synthesizing said desired range of frequencies from the output of the phase lock loop, and connecting one of the synthesized frequencies to the other input of the phase lock loop.