Key transposing electronic organ
AssigneeD. H. Baldwin Company
InventorsDavid R. Wade, Walter Munch, Jr.
Life of this patent
Estimating the term…
Abstract
A transposing electronic instrument wherein the clock frequency applied to control a top octave frequency generator is derived by comparing any single output of the generator with the response of a frequency reference circuit to that output, deriving a dc voltage representative of the difference in frequency of the input and output of the reference circuit and controlling the clock frequency from the dc voltage, thereby transposing all the outputs of the top octave frequency generator.
Claims7
A method of transposing, comprising generating a plurality of note signals by frequency division, comparing the phase of any note signal with the phase of the same note signal as processed by an all pass network tuned to a reference frequency, generating a dc control signal as a function of the comparison, generating a clock frequency in response to said dc control signal and using said clock frequency for said frequency division.
A system for transposing electronic organ music comprising a top octave frequency generating means means for selecting any one output frequency of said top octave frequency generator, a phase comparator including an all pass filter network and means for comparing the phase of an input to an output from said all pass filter network, an integrator responsive to the output of said phase comparator, a voltage controlled oscillator responsive to the output of said integrator, and means connecting the output of said voltage controlled oscillator to the input of of said top octave frequency generator.
A system for transposing electronic music, comprising an oscillator, an octave generator responsive to said oscillator and comprising means for deriving by frequency division an octave of semi-tone frequencies, switch means for selecting any one of said semi-tone frequencies, a frequency discriminator responsive to said selected semi-tone frequency and tuned to a fixed, non-generated reference frequency, and means connecting the output of said frequency discriminator to said oscillator to form a control loop whereby said frequency discriminator provides an output signal for varying the frequency of said oscillator match said selected semi-tone frequency to said reference frequency.
Dependencies are inferred from the claim text.