band extends from 200 khz to 1 mhz it is found from the characteristic curve u201c a u201d that the image signal is successfully reduced as much as 69 db or more within the target band broken line u201c b u201d in fig4 indicates an output level of the desired wave signal of the polyphase filter 17 shown in fig8 configured in five stages also assuming an output level of the desired wave signal of the polyphase filter 17 shown in fig2 as a reference level 0 db it is found from the characteristic curve u201c b u201d that the polyphase filter 17 shown in fig8 with a five stage configuration can only afford an output level of the desired wave signal lower by 4 db as compared with that for the polyphase filter 17 shown in fig2 in other words the polyphase filter 17 shown in fig2 is improved in the output level of the desired wave signal by 4 db at maximum as compared with that for the polyphase filter 17 shown in fig8 with a five stage configuration according to the polyphase filter 17 shown in fig2 even if the capacitors c 11 to c 45 thereof are composed by the mis capacitor cm effects of the capacitor cs parasitic to the mis capacitor cm can be reduced and.