Random number generating apparatus, random number generating method, program for generating random numbers, audio decoder and audio decoding method

An audio decoder apparatus comprising:

• a random number generating apparatus for generating N random numbers whose square sum has a fixed value T, comprising:
• a random number memory section in which several sets of M (M being a divisor for N) random numbers whose square sum has a fixed value R are stored;
• a random number sequence changing section in which N random numbers are generated by changing the sequence of the random numbers in more than one set of random numbers read from said random number memory section;
• a random number polarity changing section for disorderly reversing the polarity of said N random numbers;
• and
• a random number amplitude changing section for multiplying said N random number by a square root of (T×M÷R÷N);
• and
• means for generating noise having a predetermined energy within a predetermined frequency band using said random number generating apparatus.

An audio decoder apparatus comprising:

• a random number generating apparatus for generating N random numbers whose square sum has a fixed value T, comprising:
• a random number memory section in which several sets of M (M being a divisor for N) random numbers whose square sum has a fixed value R are stored;
• a random number sequence changing section in which N random numbers are generated by changing the sequence of the random numbers in more than one set of random numbers read from said random number memory section;
• and
• a random number amplitude changing section for multiplying said N random numbers by a square root of (T×M÷R÷N);
• and
• means for generating noise having a predetermined energy within a predetermined frequency band using said random number generating apparatus.

An audio decoder apparatus comprising:

• a random number generating apparatus for generating N random numbers whose square sum has a fixed value T, comprising:
• a random number memory section in which several sets of M (M being a divisor of said N) random numbers whose square sum has a fixed value R are stored;
• a random number generating section for reading more than one set of random numbers from said random number memory section to generate N random numbers;
• a random number polarity changing section for disorderly reversing the polarity of said N random numbers;
• and
• a random number amplitude changing section for multiplying said N random numbers by a square root of (T×M÷R÷N);
• and
• means for generating noise having a predetermined energy within a predetermined frequency band using said random number generating apparatus.

An audio decoding method, comprising the steps of:

• generating N random numbers whose square sum has a fixed value of T, said generating comprising the steps of:
• storing a plurality of sets of M (M is a divisor for N) random numbers whose square sum has a fixed value R;
• reading more than one set of said random numbers;
• generating N random numbers from said random numbers thus read;
• and
• multiplying said N random numbers thus generated by a square root of (T×M÷R÷N);
• and
• generating noise having a predetermined energy within a predetermined frequency band using said generated N random numbers.

An audio decoding method, comprising the steps of:

• generating N random numbers whose square sum has a fixed value T, said generating comprising the steps of:
• storing a plurality of sets of M (M is a divisor for N) random numbers whose square sum has a fixed value R;
• reading more than one set of said random numbers;
• generating N random numbers by changing the sequence of the random numbers thus read;
• reversing disorderly the polarity of said N random numbers thus generated;
• and
• multiplying said N random numbers having the disorderly reversed polarity by a square root of (T×M÷R÷N);
• and
• generating noise having a predetermined energy within a predetermined frequency band using said generated N random numbers.

An audio decoding method, comprising the steps of:

• generating N random numbers whose square sum has a fixed value T, said generating comprising the steps of:
• storing a plurality of sets of M (M is a divisor for N) random numbers whose square sum has a fixed value R;
• reading more than one set of said random numbers;
• generating N random numbers by changing the sequence of said random numbers thus read;
• and
• multiplying said N random numbers by a square root of (T×M÷R÷N);
• and
• generating noise having a predetermined energy within a predetermined frequency band using said generated N random numbers.

An audio decoding method, comprising the steps of:

• generating N random numbers whose square sum has a fixed value T, said generating comprising the steps of:
• storing a plurality of sets of M (M is a divisor for N) random numbers whose square sum has a fixed value R;
• reading more than one set of said random numbers;
• generating N random numbers from said random numbers thus read;
• reversing disorderly the polarity of said N random numbers;
• and multiplying said N random numbers by a square root of (T×M÷R÷N);
• and
• generating noise having a predetermined energy within a predetermined frequency band using said generated N random numbers.

A computer readable medium having computer readable program for operating on a computer for executing audio decoding, said program comprising instructions that cause the computer to perform the steps of:

• generating N random numbers whose square sum has a fixed value of T, said generating comprising the steps of:
• storing a plurality of sets of M (M is a divisor for N) random numbers whose square sum has a fixed value R;
• reading more than one set of said random numbers;
• generating N random numbers from said random numbers thus read;
• and multiplying said N random numbers thus generated by a square root of (T×M÷R÷N);
• and
• generating noise having a predetermined energy within a predetermined frequency band using the generated N random numbers.

A computer readable medium having computer readable program for operating on a computer for executing audio decoding, said program comprising instructions that cause the computer to perform the steps of:

• generating N random numbers whose square sum has a fixed value of T, said generating comprising the steps of:
• storing a plurality of sets of M (M is a divisor for N) random numbers whose square sum has a fixed value R;
• reading more than one set of said random numbers;
• generating N random numbers by changing the sequence of the random numbers thus read;
• reversing disorderly the polarity of said N random numbers thus generated;
• and
• multiplying said N random numbers having the disorderly reversed polarity by a square root of (T×M÷R÷N);
• and
• generating noise having a predetermined energy within a predetermined frequency band using the generated N random numbers.

A computer readable medium having computer readable program for operating on a computer for executing audio decoding, said program comprising instructions that cause the computer to perform the steps of:

• generating N random numbers whose square sum has a fixed value of T, said generating comprising the steps of:
• storing a plurality of sets of M (M is a divisor for N) random numbers whose square sum has a fixed value R;
• reading more than one set of said random numbers;
• generating N random numbers by changing the sequence of said random numbers thus read;
• and
• multiplying said N random numbers by a square root of (T×M÷R÷N);
• and
• generating noise having a predetermined energy within a predetermined frequency band using the generated N random numbers.

A computer readable medium having computer readable program for operating on a computer for executing audio decoding, said program comprising instructions that cause the computer to perform the steps of:

• generating N random numbers whose square sum has a fixed value of T, said generating comprising the steps of:
• storing a plurality of sets of M (M is a divisor for N) random numbers whose square sum has a fixed value R;
• reading more than one set of said random numbers;
• generating N random numbers from said random numbers thus read;
• reversing disorderly the polarity of said N random numbers;
• and
• multiplying said N random numbers by a square root of (T×M÷R÷N);
• and
• generating noise having a predetermined energy within a predetermined frequency band using the generated N random numbers.