Victor Company of Japan, Limited

Kikuji Wagatsuma

Hiroshi Yoshida

Naoki Yamashita

Masatsugu Kitamura

Tokumi Watanabe

Toshihiro Nishio

A system for converting a voice signal to a pitch signal comprises a first circuit for obtaining a pulse signal having a period corresponding to peak values of an input voice signal, a second circuit for quantizing the output pulse signal of the first circuit and for generating a quantized signal, a third circuit for setting a quantized signal as a preliminary pitch signal which indicates a preliminary pitch when the same quantized signal is successively obtained from the second circuit for a predetermined number of times, and a fourth circuit supplied with the quantized signal from the second circuit and the preliminary pitch signal from the third circuit for correcting the preliminary pitch signal by raising or lowering the preliminary pitch when a pitch described by the quantized signal and the preliminary pitch are not equal to each other. The fourth circuit generates a pitch signal which indicates a pitch of the input voice signal.

System for converting a voice signal to a pitch signal

In an apparatus for generating an aperiodic waveform having a gradually decaying envelope, a sequence of digital samples representing the magnitude of the waveform at sample points is stored in a memory. The stored digital samples are grouped into at least first and second continuous portions, the second portion including that portion of the sequence in which none of the digital samples has a magnitude exceeding 1/n the magnitude of the largest of the digital samples, where n is an integer greater than unity, each of the digital samples of the second portion being scaled by a factor of n. The memory further stores a code indicating the beginning of the second portion. An address counter develops an address signal for sequentially addressing the stored digital samples and code from the memory in response to clock pulses. When the stored code is addressed, an additional clock pulse is supplied from a code detector to the address counter. Each of the addressed digital samples of the first and second portions is scaled and converted to a signal having a magnitude corresponding to the magnitude of the associated digital sample of the sequence.

Aperiodic waveform generation using stored markers identifying scaled

An electronic musical instrument includes a memory in which digital samples of an aperiodic waveform are stored. Digital samples stored in a first portion of the memory represent a rapidly rising portion of the waveform and those stored in a second portion of the memory represent a rapidly declining portion of the waveform whose amplitude and spectral energy distributions are equalized. The first memory portion is addressed in forward scan and subsequently the second memory portion is addressed recyclically in forward and rearward scans to generate an output waveform having a first part corresponding to the rising waveform section and a second part corresponding to a series of the recyclically addressed versions of the equalized waveform section. After delivery of the first part of the output waveform, a monotonically declining envelope is impressed upon the amplitudes and the spectral energy distributions of the second part.

Periodic wave form generation by recyclically reading amplitude and

An electronic musical instrument includes a first memory in which audio samples of lower frequency components of an aperiodic waveform are stored and a second memory in which audio samples of a higher frequency components of the waveform are stored. Digital samples stored in a first portion of the second memory represent a rapidly rising portion of the higher frequency waveform and those stored in a second portion of the memory represent a rapidly declining portion of the higher frequency waveform whose amplitude and spectral energy distribution profiles are preferably equalized. The first memory is addressed throughout in forward scan to generate a first output waveform. The second memory is addressed in an initial forward scan throughout its first and second portions and the direction of scan is reversed at the end of the second portion to recyclically address it in rearward and forward directions to generate a second output waveform, which is combined with the first output waveform. A monotonically declining envelope is preferably impressed upon the second output waveform to reconstruct the original declining amplitude and spectral energy distribution profile.

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Sagamihara, Japan

Kikuji Wagatsuma