FIR FILTER, METHOD FOR CONTROLLING FIR FILTER, SEMICONDUCTOR INTEGRATED CIRCUIT HAVING FIR FILTER AND COMMUNICATION SYSTEM FOR TRANSMITTING DATA FILTERED BY FIR FILTER

摘要

PROBLEM TO BE SOLVED: To reduce the scale of hardware in regard to an FIR filter used by a portable terminal, etc., of a mobile communication system. SOLUTION: A filter respectively receives input data composed of transmission information and additional data added to transmit the input data. The input data is operated together wit the additional data. The difference between additional data corresponding to the previous data and additional data corresponding to the data of the current time in the input data is calculated, and the difference and the previous data are summed. These operations are repeated, and the results are outputted as filter response. The circuit scale of the filter is reduced more than in the case of receiving data which are obtained by combining the input data and the additional data and have a large bit width because the input data and the additional data are separately received and subjected to arithmetic operations. Then, the chip size of a semiconductor integrated circuit is reduced and the cost of a communication system is reduced.