the combination of the first address and the first coefficient and the combination of the second address and the second coefficient into the first coefficient storing unit as two address-coefficient pairs, and (b) in the second case writing the combination of the first address and the first coefficient into the first coefficient storing unit as an address-coefficient pair, and writing the combination of the second address and the second coefficient into the second coefficient storing unit as an address-coefficient pair; a first block storing unit having areas each of which has an address and initially stores a zero value; a second block storing unit having areas each of which has an address and initially stores a zero value; a block writing unit for (a) in the first casesequentially reading the two address-coefficient pairs from the first coefficient storing unit and writing a coefficient of each of the read address-coefficient pairs into an area in the first block storing unit specified by an address of the address-coefficient pair, and (b) in the second case reading the address-coefficient pair from the first coefficient storing unit and writing a coefficient of the read address-coefficient pair into an area in the first block storing unit specified by an address of the address-coefficient pair, and reading the address-coefficient pair from the second coefficient storing unit and writing a coefficient of the read address-coefficient pair into an area in the second block storing unit specified by an address of the address-coefficient pair; and a signal generating unit for (a) in the