Musical tone generating apparatus with reduced data storage requirements

A musical tone generating apparatus for an electronic musical instrument comprising:

• (a) first memory means for storing a group of compressed waveform data divided into a plurality of frames which correspond respectively to a plurality of frames of a waveform of a musical tone represented by said group of compressed waveform data, said group of compressed waveform data being obtained by calculating a predictive coefficient with respect to each frame of said compressed waveform data group and effecting a predictive coding operation on instantaneous values of each frame of said compressed waveform data group using a corresponding one of the calculated predictive coefficients;
• (b) second memory means for storing said calculated predictive coefficients;
• (c) first reading means for reading said group of compressed waveform data from said first memory means;
• (d) second reading means for reading said calculated predictive coefficients in synchronization with the reading of frames of said compressed waveform data group;
• and
• (e) decoding means for decoding the read compressed waveform data group, by effecting a decoding operation corresponding to said predictive coding operation on each frame of said read compressed waveform data group using a respective one of the read predictive coefficients, to thereby obtain a group of decoded waveform data, said musical tone being reproduced from said decoded waveform data.

A musical tone generating apparatus for an electronic musical instrument comprising:

• (a) memory means for storing a series of compressed waveform data therein, said series of compressed waveform data being obtained by compressing a series of waveform data representative of instantaneous values of a waveform of a musical tone by use of either one of a predictive coding method and a modulation method;
• (b) data providing means for providing replacement data;
• (c) reading means for repeatedly reading at least one portion of said series of compressed waveform data from said memory means, said replacement data corresponding to data preceding said at least one portion in time among said series of compressed waveform data;
• (d) circuit means for replacing the first compressed waveform data of said at least one portion with said replacement data to output a group of compressed waveform data;
• and
• (e) decoding means for decoding said group of compressed waveform data by a decoding method corresponding to said one method to obtain a series of decoded waveform data, said musical tone being reproduced based on said series of decoded waveform data.

A waveform data processing system for a musical tone generating apparatus comprising:

• (1) dividing means for dividing a waveform of a musical tone, represented by a series of sample values of an amplitude of said musical tone, into a plurality of frames arranged in terms of time;
• and
• (2) predictive coefficient calculating means for calculating, with respect to each frame, a predictive coefficient from the sample values of said each frame, each of the calculated predictive coefficients being for use in a predictive operation to be effected on the sample values of a respective one of said plurality of frames to calculate predicted values of said sample values, said predicted values representing an approximated waveform of said waveform and being used to determine compressed waveform data representative of the waveform;
• memory means for storing the compressed waveform data;
• means for designating the pitch of a tone to be generated;
• and
• reading means for reading out the compressed waveform data at a speed corresponding to the designated pitch.

A musical tone generating apparatus for an electronic musical instrument comprising:

• (1) memory means for storing a series of compressed waveform data which have been obtained by compressing a series of waveform data representative of instantaneous values of a waveform of a musical tone by a predictive coding method;
• (2) coefficient generating means for generating predictive coefficient data representative of a predictive coefficient of a first predictive operation to be used in said predictive coding method, said predictive coefficient data varying in accordance with a lapse of time;
• and
• (3) waveform data reproducing means for reproducing said series of waveform data from said compressed waveform data by effecting a second predictive operation on said compressed waveform data using said predictive coefficient data, said second predictive operation being related with said first predictive operation.

A musical tone generating apparatus for an electronic musical instrument comprising:

• (1) memory means for storing a series of compressed waveform data which have been obtained by compressing a series of waveform data representative of instantaneous values of a waveform of a musical tone by a predictive coding method;
• (2) data providing means for providing replacement data;
• (3) reading means for repeatedly reading at least one portion of said series of compressed waveform data from said memory means, said replacement data corresponding to data preceding said at least one portion in time among said series of compressed waveform data;
• (4) circuit means for replacing the first compressed waveform data of said at least one portion with said replacement data to output a group of compressed waveform data;
• and
• (5) decoding means for decoding said group of compressed waveform data by a decoding method corresponding to said predictive coding method to obtain a series of decoded waveform data, said musical tone being reproduced from said series of decoded waveform data.

A musical tone generating apparatus for an electronic musical instrument comprising:

• (1) memory means for storing a series of compressed waveform data which have been obtained by compressing a series of waveform data representative of instantaneous values of a waveform of a musical tone by a differential quantization method;
• (2) data providing means for providing replacement data;
• (3) reading means for repeatedly reading at least one portion of said series of compressed waveform data from said memory means, said replacement data corresponding to data preceding said at least one portion in time among said series of compressed waveform data;
• (4) circuit means responsive to said replacement data and said at least one portion for replacing the first compressed waveform data of said at least one portion with said replacement data to output a group of compressed waveform data;
• and
• (5) decoding means for decoding said group of compressed waveform data by a decoding method corresponding to said differential quantization method to obtain a series of decoded waveform data, said musical tone being reproduced from said series of decoded waveform data.

A waveform data processing system for a musical tone generating apparatus comprising:

• (1) approximated waveform data generating means for generating a series of approximated data of a series of waveform data, representative of instantaneous values of a musical tone waveform, by effecting a predictive operation and a differential quantization operation on predetermines ones of said series of waveform data, said series of approximated data representing an approximated waveform of said musical tone waveform;
• (2) operation means for effecting a predetermined operation on said series of waveform data and said series of approximated data to produce a series of compressed waveform data;
• and
• (3) memory means for storing said compressed waveform data for subsequent readout for generation of musical tones.

A musical tone generating apparatus for an electronic musical instrument comprising:

• (1) memory means for storing a series of compressed waveform data which have been obtained by compressing a series of waveform data, representative of instantaneous values of a waveform of a musical tone, by effecting a predictive operation and a differential quantization operation on predetermined ones of said series of waveform data;
• (2) reading means for reading said series of compressed waveform data from said memory means;
• and
• (3) decoding means for decoding said read series of compressed waveform data by effecting operations corresponding respectively to said predictive operation and said differential quantization operation on said read series of compressed waveform data to obtain a series of decoded waveform data, said musical tone being reproduced from said series of decoded waveform data.

A waveform data processing system for a musical tone generating apparatus comprising:

• (1) approximated waveform data generating means for generating a series of approximated data of a series of waveform data, representative of instantaneous values of a waveform relating to a musical tone, by effecting a predictive operation and a differential quantization operation on a predetermined ones of said series of waveform data, said series of approximated data representing an approximated waveform of said musical tone waveform;
• (2) operation means for effecting a predetermined operation on said series of waveform data and said series of approximated data to produce a series of compressed waveform data;
• (3) memory means for storing said series of compressed waveform data;
• (4) reading means for reading said series of compressed waveform data from said memory means;
• and
• (5) decoding means for decoding said read series of compressed waveform data by effecting operations corresponding respectively to said predictive operation and said differential quantization operation on said read series of compressed waveform data to obtain a series of decoded waveform data, said musical tone being reproduced from said series of decoded waveform data.

A musical tone generating apparatus for an electronic musical instrument comprising:

• (1) operation means for performing an operation on a series of waveform data representative of instantaneous values of a waveform of a musical tone and a series of predicted data of said series of waveform data to output a series of operated waveform data;
• (2) first processing means having first compressing means for compressing said series of operated waveform data to output a series of first compressed waveform data and first reproducing means for reproducing said series of operated waveform data by performing an inverse operation of said first compressing means on said series of first compressed waveform data;
• and
• (3) second processing means having second compressing means for compressing said first compressed waveform data to produce a series of second compressed waveform data for determining said series of predicted data.