Transceiver with switchable frequency band and bandwidth

Abstract

Abstract The invention relates to a transceiver, which in the FDD mode of operation receives at a first frequency (F1) and transmits at a second frequency (F2); and in the TDD mode of operation receives and transmits at a third frequency (F3); and which incorporates in the receiving branch at least a first mixer (2) for forming a first intermediate frequency (IF1) from the received frequency (F1, F3) and the first local oscillator frequency (LO1); and a second mixer (7) for forming a second intermediate frequency (1F2) from the first intermediate frequency (IF1) and the second local oscillator frequency (LO2) and in the transmission branch at least: a modulator (15) for modulating the signals to be transmitted (TXI, TXQ) to the third intermediate frequency (IF3); a third mixer (16) for forming the transmission frequency (F2, F3) from the third intermediate frequency (IF3) and the fourth local oscillator frequency (LO4), first synthesizer means (17) for forming equally high first and fourth local oscillator frequencies (LO1, LO4); and second synthesizer means (12) and a frequency multiplier or divider (14a) and switching means (13) for forming and switching a fourth frequency (FS) and its M times multiple (M*FS) according to the invention, so that the fourth frequency (FS) is the 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), whereby in the FDD mode of operation the fourth frequency (FS) is switched as the third local oscillator frequency (LO3) and its said multiple (M*FS) as the second local oscillator frequency (LO2), if the reception frequency (F1) of the FDD mode of operation is higher than the transmission frequency (F2), and the fourth frequency (FS) is switched as the second local oscillator frequency (LO2), and its said multiple (M*FS) as the third local oscillator frequency (LO3), if the reception frequency (F1) of the FDD mode of operation is lower than the transmission frequency (F2), and in the TDD mode of operation either a fourth frequency (FS) or its said multiple (M*FS) is switched as both the second local oscillator frequency (LO2) and the third local oscillator frequency (LO3).

Inventors

• 👤 Kari Lehtinen
• 👤 Mikko Pesola

Bibliographic Details