PURPOSE: To reduce processing delay caused between the input and output signals and to reduce the memory capacity by starting a filter arithmetic operation of the unit of block from the timing where the number of samples of wide band signals to be inputted are counted and the 1st and 2nd arithmetic operations can be carried out.
CONSTITUTION: A partial arithmetic operation is carried out by an arithmetic part 4 based on an equation I right after a wide band signal x (Mm-M/2-1) of rising of a 1st timing signal is inputted from a wide band signal input/output part 5. Thus a 1st intermediate signal W1(n) is calculated. Then a 2nd arithmetic operation is started by the part 4 based on an equation II right after the falling timing of the 1st timing signal. The sub-band signals y(O, Mm) are calculated and successively outputted from a sub-band signal input/output part 6. Thus the sample of a wide band input signal affects both the result of filter calculation and the sample of a sub-band output signal. Therefore the processing delay caused between the input of a wide band signal and the output of the corresponding sub-band signal is equal to one sample and therefore can be extremely decreased from M samples.
NAGAI KIYOTAKA
NAKAJIMA KOJI
