The LC89602 is an audio decoder LSI for mini-disk playback units. This LSI implements the processing that precedes the D/A converter in playback-only mini-disk players. That is, the LC89602 receives data in sound frame units from a mini-disk data decoder LSI (such as the Sanyo LC89610), expands the audio signal and decoder that signal directly to a D/A converter. This audio expander LSI accepts audio data that has been compressed by a factor of about 5 to 1, and expands that data to audio data that is equivalent to that from a CD player, namely 16-bit quantized data with a 44.1 kHz sampling frequency. Since this expansion consists of complex operations involving discrete cosine transformations and digital filtering, if the computations performed on this 16-bit data were performed with a 16-bit precision, the arithmetic errors associated with the calculations would result in arithmetic noise in the lower bits and a full 16 bits of precision would not be acquired. Inversely, increasing the number of registers and the bus width to improve the precision of the arithmetic would increase the size of the circuit and the power required. The LC89602 was optimized to achieve both the low power required by portable units as well as the high-precision arithmetic required by home units.