Transceiver with switchable frequency band and bandwidth

摘要

A transceiver is described which in a FDD mode of operation receives at a first frequency (F1) and transmits at a second frequency (F2); and in a TDD mode of operation receives and transmits at a third frequency (F3). The transceiver incorporates in a receiving branch at least a first mixer for forming a first intermediate frequency (IF1) from a received frequency (F1, F3) and a first local oscillator frequency (LO1); and a second mixer for forming a second intermediate frequency (IF2) from the first intermediate frequency (IF1) and the second local oscillator frequency (LO2). In a transmission branch the transceiver includes a modulator for modulating signals to be transmitted (TXI, TXQ) to a third intermediate frequency (IF3); a third mixer (16) for forming a transmission frequency (F2, F3) from a third intermediate frequency (IF3) and a fourth local oscillator frequency (LO4). Also included is a first synthesizer for forming equally high first and fourth local oscillator frequencies (LO1, LO4), and a second synthesizer and a frequency multiplier or divider and a switching arrangement for forming and switching a fourth frequency (FS) and its M times multiple (M*FS) such that the fourth frequency (FS) is an absolute value of the difference between the reception frequency (F1) and the transmission frequency (F2) of the FDD mode of operation divided by (M-1).