Tuning indicator for musical instruments
AssigneeKawai Musical Instrument Mfg. Co., Ltd.
InventorRalph Deutsch
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Abstract
A tuning indicator is disclosed in which the octave, note within the octave, and a tuning error is displayed for a musical tone played into a microphone. A bank of digital octave filters, a bank of digital note filters, a bank of digital cent filters operate simultaneously and in parallel to analyze the fundamental frequency of the musical tone. The filters operate by computing the autocorrelation function of the input signal and then performing a Fourier transform to obtain the frequency analysis data. An efficient and simple implementation is disclosed for the computations including the analog-to-digital signal conversion, the computation of the autocorrelation function, and the Fourier transform.
Claims13
Apparatus for indicating the tuning error of a tone produced by a musical instrument comprising;
- a conversion means for converting said tone into a waveshape signal,
- an octave detection means whereby an octave signal is generated in response to said waveshape signal,
- a note detection means whereby a note signal is generated in response to said waveshape signal and in response to said octave signal,
- a cent detection means whereby a cent signal is generated in response to said waveshape signal and in response to said note signal, and
- a tuning display means whereby said tuning error is indicated in response to said octave signal, said note signal, and said cent signal.
Dependencies are inferred from the claim text.