JPS6485412A - Frequency characteristic setting device - Google Patents

Abstract

PURPOSE:To drastically reduce the arithmetic time obtaining a filter coefficient by dividing the frequency band into those corresponding to plural different sampling frequencies so as to reduce the number of processed data in each frequency band. CONSTITUTION:An input circuit 1 receives an optional group delay frequency characteristic, an integration circuit 2 uses a frequency to integrate the inputted group delay frequency characteristic and a split circuit 3 divides the phase frequency characteristic obtained by the circuit 2 into frequency bands corresponding to two different sampling frequencies. An arithmetic circuit 4 obtains the filter coefficient of FIR filters 5, 6 corresponding to the split phase frequency characteristic by the circuit 3 and the amplitude frequency characteristic corrected to bring the realized amplitude frequency characteristic to the unity. The sampling frequency of the FIR filters 5, 6 differ from each other and the number of the filter coefficient is the same. Then the arithmetic time to obtain the filter coefficient of the FIR filters to realize a desired group delay frequency characteristic is drastically reduced.