Musical tone-generating method and apparatus using data interpolation

A musical tone-generating method of generating musical tones by reading waveform data from a waveform table at a predetermined sampling frequency and carrying out arithmetic operations on said waveform data read from said waveform table to generate musical tone waveform samples, by the use of a processing unit operating on a software tone generator program,

• the method comprising the steps of:
• selecting a first sampling frequency or a second sampling frequency lower than said first sampling frequency as said predetermined sampling frequency;
• and
• inhibiting interpolation of said waveform data read from said waveform table, to generate a musical tone having high-frequency components containing aliasing noise, when said second sampling frequency is selected as said predetermined sampling frequency.

In a musical tone-generating apparatus having a processing unit operating on a software tone generator program for reading waveform data from a waveform table at a predetermined sampling frequency, and carrying out arithmetic operations on said waveform data read from said waveform table to generate musical tone waveform samples,

• the improvement wherein:
• said processing unit includes first interpolating means for interpolating said waveform data read from said waveform table by a first interpolation method, and second interpolating means for interpolating said waveform data read from said waveform table by a second interpolation method which is lower in accuracy than said first interpolation method;
• and
• said musical tone-generating apparatus comprises:
• sampling frequency-selecting means for selecting a first sampling frequency or a second sampling frequency lower than said first sampling as said predetermined sampling frequency;
• and
• control means for causing said second interpolating means to interpolate said waveform data read from said waveform table, to generate a musical tone having high-frequency components containing aliasing noise, when said second sampling frequency is selected by said sampling frequency-selecting means.

In a musical tone-generating apparatus having a processing unit operating on a software tone generator program for reading waveform data from a waveform table at a predetermined sampling frequency, and carrying out arithmetic operations on said waveform data read from said waveform table to generate musical tone waveform samples,

• the improvement wherein:
• said processing unit includes interpolating means for interpolating said waveform data read from said waveform table;
• and
• said musical tone-generating apparatus comprises:
• sampling frequency-selecting means for selecting a first sampling frequency or a second sampling frequency lower than said first sampling as said predetermined sampling frequency;
• and
• interpolation-inhibiting means for inhibiting said interpolating means from interpolating said waveform data read from said waveform table, to generate a musical tone having high-frequency components containing aliasing noise when said second sampling frequency is selected by said sampling frequency-selecting means.

A machine readable storage medium-storing instructions to cause a machine to perform a musical tone-generating method of generating musical tones by reading waveform data from a waveform table at a predetermined sampling frequency and carrying out arithmetic operations on said waveform data read from said waveform table to generate musical tone waveform samples, by the use of a processing unit operating on a software tone generator program,

• the method comprising the steps of:
• selecting a first sampling frequency or a second sampling frequency lower than said first sampling frequency as said predetermined sampling frequency;
• and
• interpolating said waveform data read from maid waveform table by a second interpolation method which is lower in accuracy than a first interpolation method employed when said first sampling frequency is used, to generate a musical tone having high-frequency components containing aliasing noise, when said second sampling frequency is selected as said predetermined sampling frequency.