Chifumi Takeuchi

Musical tone synthesizing apparatus utilizing an all-pass filter having a variable fractional delay

The musical tone synthesizing apparatus is mainly configured by a closed loop which at least provides a delay circuit and an all-pass filter. The delay circuit delays an input signal (e.g., excitation wave signal) by a first delay time corresponding to a certain integral number of sampling periods. The all-pass filter functions to at least delay an output of the delay circuit by a second delay time corresponding to a decimal fraction of the sampling period, so that an output of the all-pass filter is fed back to the delay circuit. The whole delay time of the closed loop consists of the first and second delay times which can be respectively controlled. Thus, a musical tone signal representing a synthesized musical tone (e.g., an attenuating sound which is produced from an percussion instrument) is picked up from the closed loop. Incidentally, the whole configuration of the closed loop can be embodied by a digital signal processor (DSP).

Device for synthesizing a musical tone employing random modulation of a wave form signal

An apparatus for synthesizing a musical tone comprises a loop circuit for circulating an input wave form signal through a delay circuit, a wave form memory, and a random modulation circuit for modulating the wave form signal stored in the wave form memory. The random modulation circuit generates a random signal, such as a noise signal. The random signal modulates address data to the wave form memory, so that the read wave form data read out from the wave form memory is delicately varied with time.

Musical tone generating device with simulation of harmonics technique of a stringed instrument

A musical tone generating device is capable of simulating various special playing techniques for a stringed instrument in which the harmonic spectrums of produced sound is enhanced, or otherwise altered. The device includes a delay circuit wherein an input signal thereto is delayed and output; a closed loop circuit comprising multiple feedback pathways to which the output of the delay circuit is supplied and processed therein, after which the processed signal is returned toward the delay circuit as an input signal; an excitation device in response to a predetermined control signal, generating an excitation signal and supplying it to the closed loop circuit, such that the excitation signal corresponds to an excitation vibration in the stringed instrument being simulated; and a control device wherein the predetermined control signal is generated and whereby the delay interval of the delay circuit and the processing carried out in the multiple feedback pathways are controlled.

Musical sound signal synthesizer and method for synthesizing musical sound signals using nonlinear transformer

A musical sound signal synthesizer with a simple construction for synthesizing complex musical sound waveform signals including many harmonics in a peculiar form. A phase information generator 11 supplies phase information x with a sawtooth wave changing according to a phase of the musical sound to be generated via a calculator 12 to a sine wave table 13, from which output waveform information y is read out. The waveform information y is fed back to the calculator 12 via an absolute value transformer 14, a low pass filter 15 and a gain controller 16. The output waveform information y outputted from the sine table 13 is transformed nonlinearly, which is fed back to the phase information x, which makes a complex change. As a result thereof, the waveform, which is represented by waveform information outputted from the sine wave table 13, becomes peculiar for a musical sound signal synthesized by phase or frequency modulation technique.