FIELD: communications engineering. SUBSTANCE: proposed method and device enable operation in plurality of frequency bands dispensing with necessity of having mixer 234 for each band. For instance, local oscillator input frequencies for both bands (GSM and DCS) in double-band GSM/DCS radiophone 1800 are supplied from mixer 234 by using integrating filters 222, 246. In this way requirements to duplex mode and matching at input of mixer 234 are satisfied and signal loss is minimized. GSM and DCS outputs of integrating and adding filters are connected in duplex manner to input of mixer 234. Provision is made for matching input impedance of filter 234 for signals received in each band. Provision is also made for matching impedance of intermediate-frequency filter 260 ensuring low impedance for input radio frequencies. Three-band radiophone is also described. EFFECT: minimized signal loss. 7 cl, 5 dwg
