초록 ▼

The present invention relates to an arrangement for transmitting a radio-frequency signal at two different frequency bands and for receiving at two different frequency bands. The arrangement can be applied for instance to a transceiver of a radio communications system operating at two different freq

The present invention relates to an arrangement for transmitting a radio-frequency signal at two different frequency bands and for receiving at two different frequency bands. The arrangement can be applied for instance to a transceiver of a radio communications system operating at two different frequency bands, or to a transceiver meant to be used in connection with two different radio communications systems. One of the ideas of the invention is that one and the same filter (72), belonging to the RF front end of the antenna circuit, is used for filtering interference from at least two signals located at different frequency bands, in which case the number of filters (72, 75) can be reduced. By means of the solution suggested in the invention, also the number of controllable switches (73) provided on the signal path of the RF front end can be minimized.

대표청구항 ▼

[ What is claimed is:] [1.] An apparatus for transmitting and receiving RF signals, the apparatus enabling a transmission to take place at a first transmitter frequency band (TX, TX1) and at a second transmitter frequency band (TDD, TX2), said first and second transmitter frequency bands being separ

[ What is claimed is:] [1.] An apparatus for transmitting and receiving RF signals, the apparatus enabling a transmission to take place at a first transmitter frequency band (TX, TX1) and at a second transmitter frequency band (TDD, TX2), said first and second transmitter frequency bands being separate, so that a reception can take place at a first receiver frequency band (RX, RXI) and at a second receiver frequency band (TDD, RX2), said first and second receiver frequency bands being separate, said apparatus comprising:filtering means for filtering a signal to be received and transmitted, said filtering means comprising a first, a second, and a third filter means of which at least one of said filter means serves for filtering signals located in at least two different frequency bands;a first amplifier means for amplifying a first signal and a second signal after reception and filtering, and a second amplifier means for amplifying a third signal and a fourth signal prior to filtering and transmission;a switch (32) having at least two modes and serving to couple said apparatus to an antenna circuit (38);wherein said switch (32) is arranged, in a first of the two modes, to couple the antenna circuit (38) to a first connection of the first, and third filter means (33, 36) in order to direct the first signal from the antenna circuit (38) to the first filter means (33) and in order to direct the third and fourth signal from the third filter means (36) to the antenna circuit (38);a second connection of the first and second filter means (33, 34) is coupled to the input of the first amplifier means (35) in order to direct the first signal from the first filter means (33) to the first amplifier means (35) and in order to direct the second signal from the second filter means (34) to the first amplifier means (35);said switch means (32) is arranged, in the second mode, to couple the antenna circuit (38) to the second filter means (34) in order to direct the second signal from the antenna circuit (38) to the second filter means (34); anda second connection of said third filter means (36) is coupled to the output of the second amplifier means (37) in order to direct the third and fourth signal from the second amplifier means (37) to the third filter means (36).