Patent ID: 6317608
Filing Date: 2001-11-13
Classification: H04B

Abstract:
A power amplifier output circuit for a dual band mobile radio unit, comprising:a first transmitter/receiver change over unit for transmitting/receiving a first transmitting/receiving signal, said first transmitter/receiver change over unit being provided with an input terminal receiving said first transmitting signal to which a first impedance matching unit is connected,a second transmitter/receiver change over unit for transmitting/receiving a second transmitting/receiving signal,a transmission branch change over unit to selectively connect said first transmitter/receiver change over unit or said second transmitter/receiver change over unit to a power amplifier outputting transmitting signals in two frequency bands, whereina second impedance matching unit is provided between an output terminal of said power amplifier and said transmission branch change over unit,the transmission branch change over unit comprises at least two switching elements being connected in parallel in a first transmission branch which connects said power amplifier with said first transmitter/receiver change over unit,a third impedance matching unit is provided at an input terminal of said second transmitter/receiver change over means, anda switchable band stop filter is provided downstream said third impedance matching means that filters harmonics of said first transmitting signal in said second transmission branch during the transmission of said first transmitting signal.