A method of controlling the frequency of a first local signal and a second local signal based on a frequency of a radio frequency (RF) signal input to an up-down converter comprising: a first mixer (115-1) configured to convert an input radio frequency (RF) signal into an intermediate frequency (IF) signal using a first local signal; an IF filter configured to filter the IF signal converted by the first mixer (115-1); a second mixer (115-2) configured to convert the IF signal, which has been filtered by the IF filter , into an output RF signal using a second local signal; a local oscillator configured to control a frequency of the first local signal and the second local signal based on the input RF signal; a first RF filter (114-1) configured to filter the input RF signal and to transmit a filtered input RF signal to the first mixer (115-1); and a second RF filter (114-2) configured to filter out an image frequency from the output RF signal, wherein the input RF signal comprises a plurality of frequency bands comprising a first (RB1) and a second frequency band (RB2), wherein a width of a filtering band of the IF filter is the same as or greater than a bandwidth of a frequency band having the greatest bandwidth among the plurality of frequency bands, the method being characterized in that the first local signal and the second local signal are controlled (i) so that the first frequency band (RB1) passes through the IF filter within a partial frequency section (PF1) of the filtering band, (ii) and so that the partial frequency section (PF1) is at a side of said filtering band (FB1) closest to the second frequency band (RB2) wherein the second frequency band (RB2) is nearest to the first frequency band (RB1) of the input RF signal, wherein the second RF filter pass all of the plurality of frequency bands. a first mixer (115-1) configured to convert an input radio frequency (RF) signal into an intermediate frequency (IF) signal using a first local signal; an IF filter configured to filter the IF signal converted by the first mixer (115-1); a second mixer (115-2) configured to convert the IF signal, which has been filtered by the IF filter , into an output RF signal using a second local signal; a local oscillator configured to control a frequency of the first local signal and the second local signal based on the input RF signal; a first RF filter (114-1) configured to filter the input RF signal and to transmit a filtered input RF signal to the first mixer (115-1); and a second RF filter (114-2) configured to filter out an image frequency from the output RF signal, wherein the input RF signal comprises a plurality of frequency bands comprising a first (RB1) and a second frequency band (RB2), wherein a width of a filtering band of the IF filter is the same as or greater than a bandwidth of a frequency band having the greatest bandwidth among the plurality of frequency bands, the method being characterized in that the first local signal and the second local signal are controlled (i) so that the first frequency band (RB1) passes through the IF filter within a partial frequency section (PF1) of the filtering band, (ii) and so that the partial frequency section (PF1) is at a side of said filtering band (FB1) closest to the second frequency band (RB2) wherein the second frequency band (RB2) is nearest to the first frequency band (RB1) of the input RF signal, (i) so that the first frequency band (RB1) passes through the IF filter within a partial frequency section (PF1) of the filtering band, (ii) and so that the partial frequency section (PF1) is at a side of said filtering band (FB1) closest to the second frequency band (RB2) wherein the second frequency band (RB2) is nearest to the first frequency band (RB1) of the input RF signal, wherein the second RF filter pass all of the plurality of frequency bands. <EOS>