Patent
Method of generating a tone signal
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TLDR
In this paper, a tone synthesis modulation operation is performed, using this waveshape data as at least one of a signal to be modulated and a modulating signal is generated in a tone signal generated in response to the resampled signal.Abstract:
A tone generation system and method generates tone signals having complex harmonic components while reducing aliasing noise resulting from sampling of high frequency harmonics. In a first step, waveshape data which has been sampled with a second sampling frequency which is higher than a first sampling frequency is obtained. Then a predetermined tone synthesis modulation operation is performed, using this waveshape data as at least one of a signal to be modulated and a modulating signal. By performing this modulation operation in accordance with the higher second sampling frequency, occurrence of an aliasing component contained in a tone signal obtained as the output of the modulation operation in a frequency band below a frequency which is 1/2 of the first sampling frequency can be prevented. Then, the frequency band of the output signal of the modulation operation is limited to a frequency band below the frequency which is 1/2 of the first sampling frequency. By this arrangement, even if an aliasing noise component concerning the second sampling frequency occurs in a frequency region which is higher than the frequency which is 1/2 of the first sampling frequency, such aliasing noise component will be eliminated. Lastly the output signal of the third step is resampled with the first sampling frequency. In this manner, in a tone signal generated in response to the resampled signal, an aliasing component concerning the first sampling frequency becomes higher than 1/2 of the first sampling frequency so that it does not appear as the aliasing noise.read more
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References
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Journal ArticleDOI
Electronic musical instrument
Nagai Youhei,Okamoto Shimaji +1 more
TL;DR: In this article, the tone signal generated by one of the tone generators is passed through a frequency shifter, while the tone generated by the rest of the keyers is not, and then the two signals are mixed together and finally transduced into sound by a loudspeaker.
PatentDOI
Sound effect imparting device for an electronic musical instrument
Tsuyoshi Futamase,Mitsumi Kato +1 more
TL;DR: In this paper, a sound effect imparting device for an electronic musical instrument is capable of imparting a plurality of desired sound effect such as vibrato and reverberation effects to a digital musical tone generated from the EMI.
Patent
Decimator apparatus for decreasing the word rate of a digital signal of the type employed in digital telephone systems
TL;DR: In this article, a decimator structure which incorporates the cascade of an FIR filter with a low pass recursive filter is described. But the decimators are not implemented by conventional hardware multipliers and hence, affords efficient and economical circuit components.
PatentDOI
Electronic musical instruments
Takeshi Adachi,Eisaku Okamoto +1 more
TL;DR: In this article, the electronic musical instrument is provided with a plurality of musical tone generating channels of a number smaller than that of the keys and a channel processor for randomly assigning key information representing depressed keys to the musical tone generator channels.
PatentDOI
Tone signal processing device
TL;DR: In this paper, a digital filter is provided between a tone signal generation circuit and a sampling circuit which resamples this digital tone signal in accordance with a second sampling frequency which is lower than the first sampling frequency.