Arrangement for transmitting and receiving radio frequency signal at two frequency bands

• US 6,014,551 A
• Filed: 07/16/1997
• Issued: 01/11/2000
• Est. Priority Date: 07/18/1996
• Status: Expired due to Term

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Lehtinen, Kari T., Pesola, Mikko
• Primary Examiner(s): Hudspeth, David R.
• Assistant Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US08/893,952
• Time in Patent Office: 909 Days
• Field of Search: 455/552, 455/553, 455/575, 455/82, 455/83, 455/84, 455/78, 455/219, 375/260, 375/295, 375/296, 375/219, 375/275, 375/267, 375/347, 375/356
• US Class Current: 455/86
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions

Abstract

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.

Claims

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); and

a 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).

7. Use of an arrangement according to claim 1 in a communication arrangement, wherein

the second transmitter frequency band (TDD) and the second receiver frequency band (TDD) are at least partly overlapping, and

the distance of the first transmitter frequency band (TX) from the second transmitter frequency band (TDD) and from the second receiver frequency band (TDD) is shorter than from the first receiver frequency band (RX).

2. 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, and a second 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 first connection of the first, and second filter means (42,

     44) serving for coupling the apparatus to an antenna circuit (41) in order to direct the first signal from the antenna circuit (41) to the first filter means (42), in order to direct the second signal from the antenna circuit (41) to the second filter means (44), in order to direct the third signal from the second filter means (44) to the antenna circuit (41), and in order to direct the fourth signal from the second filter means (44) to the antenna circuit (41);

a switch (45) having at least two modes, one of said modes serving for connection of said switch to a first connection of the second filter means (44);

wherein said switch (45), in a first of the two modes, is arranged to couple a second connection of the second filter means (44) to the input of the first amplifier means (43) in order to direct the second signal from the second filter means (44) to the first amplifier means (43); and

said switch (45) is arranged, in the second of the two modes, to couple a second connection of the second filter means (44) to the output of the second amplifier means (46) in order to direct the third and fourth signal from the second amplifier means (46) to the second filter means (44).

3. 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 (62) serving to connect said apparatus to an antenna circuit (61), and having at least two modes;

wherein said switch (62), in a first of the two modes, is arranged to couple the antenna circuit (61) to a first connection of the first and third filter means (63,

     66) in order to couple the first and second signals from the antenna circuit (61) to the first filter means (63), and in order to couple the third signal from the third filter means (66) to the antenna circuit;

a second connection of the first filter means (63) is coupled to the input of the first amplifier means (64) in order to direct the first and second signals from the first filter means (63) to the first amplifier means (64);

a second connection of the third filter means (66) is coupled to the output of the second amplifier means (67) in order to direct the third signal from the third amplifier means (67) to the third filter means (66);

said switch (62), in a second of the two modes, is arranged to couple a first connection of the second filter means (65) to the antenna circuit (61) in order to direct the fourth signal from the second filter means (65) to the antenna circuit (61); and

a second connection of the second filter means (65) is coupled to the output of the second amplifier means (67) in order to direct the fourth signal from the second amplifier means (67) to the second filter means (65).

8. Use of an arrangement according to claim 3 in a communication arrangement, wherein

the second transmitter frequency band (TDD) and the second receiver frequency band (TDD) are at least partly overlapping, and

the distance of the first receiver frequency band (RX) from the second transmitter frequency band (TDD) and from the second receiver frequency band (TDD) is shorter than the distance from the first transmitter frequency band (TX).

4. 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, and a second, 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 first connection of said first, and second filter means (72,

     75) serving for coupling the apparatus to an antenna circuit (71);

wherein a second connection of the second filter means (75) is coupled to the output of the second amplifier means (76) in order to filter the third signal and feed it to the antenna circuit (71);

the apparatus further comprises a switch (73), coupled to a second connection of the first filter means and the second connection of the second filter means and having at least two modes;

said switch, in a first of the two modes, is arranged to couple the second connection of the first filter means to the first amplifier means (74) in order to direct the first and second signals from the first filter means (72) to the first amplifier means (74); and

said switch (73), in a second of the two modes, is arranged to couple the output of the second amplifier means (76) to the second connection of the first filter means (72) in order to direct the fourth signal to the antenna circuit (71) via the first filter means (72).

5. 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, and a second 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 (92) having at least two modes, and serving for coupling the apparatus to an antenna circuit (91);

wherein, in a first of the two modes said switch (92) is arranged to couple the antenna circuit (91) to a first connection of the first filter means (93) in order to direct the first and second signals from the antenna circuit (91) to the first filter means (93);

a second connection of the first filter means (93) is coupled to the input of the first amplifier means (94) in order to direct the first and second signals from the first filter means (93) to the first amplifier means (94);

in the second of the two modes, said switch (92) is arranged to switch a first connection of the second filter means (95) to the antenna circuit (91), and to direct the third and fourth signals from the second filter means (95) to the antenna circuit (91); and

a second connection of the second filter means (95) is coupled to the output of the second amplifier means (96) in order to direct the third and fourth signals from the second amplifier means (96) to the second filter means (95).

9. Use of an arrangement according to claim 5 in a communication arrangement, wherein

the second transmitter frequency band (TDD) and the second receiver frequency band (TDD) are at least partly overlapping, and

the distance of the first receiver frequency band (RX) from the first transmitter frequency band (TX) is shorter than the distance from the second receiver frequency band (TDD) and from the second transmitter frequency band (TDD).

6. 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 (112), having at least two modes, and serving to couple the apparatus to an antenna circuit (111);

wherein, in a first of the two modes said switch (112) serves for coupling the antenna circuit (111) to a first connection of the first and second filter means (113,

     114) in order to direct the first signal from the antenna circuit (111) to the first filter means (113), and in order to direct the second signal from the antenna circuit (111) to the second filter means (114);

a second connection of the first and second filter means (113,

     114) is coupled to the input of the first amplifier means (115) in order to direct the first signal from the first filter means (113) to the first amplifier means (115), and in order to direct the second signal from the second filter means (114) to the first amplifier means (115);

in the second of the two modes, said switch (112) is arranged to switch the antenna circuit (111) to a first connection of the third filter means (116) in order to direct the third and fourth signals from the third filter means (116) to the antenna circuit (111); and

an output of the second amplifier means (117) is coupled to a second connection of the third filter means (116) in order to direct the third and fourth signals from the second amplifier means (117) to the third filter means (116).

10. Use of an arrangement according to claim 6 in a communication arrangement, wherein

the first transmitter frequency band (TX1), the second transmitter frequency band (TX2), the first receiver frequency band (RX1) and the second receiver frequency band (RX2) are separate from each other, and

the distance between the first transmitter frequency band (TX1) and the first receiver frequency band (RX1) as well as the distance between the second transmitter frequency band (TX2) and the second receiver frequency band (RX2) are shorter then the distance of the first transmitter frequency band (TX1) and the first receiver frequency band (RX1) from the second transmitter frequency band (TX2) and the second receiver frequency band (RX2).

11. Apparatus, adapted for connection to an antenna, for transmitting and receiving RF signals, the apparatus enabling a transmission to take place at a first transmitter frequency band and at a second transmitter frequency band, said first and second transmitter frequency bands being separate, so that a reception can take place at a first receiver frequency band and at a second receiver frequency band, 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, a third, and a fourth filter of which at least one of said filters serves for filtering signals located in at least two different frequency bands;

a first amplifier for amplifying a first signal and a second signal after reception and filtering, and a second amplifier for amplifying a third signal and a fourth signal prior to filtering and transmission, wherein each of said filters has a first connection point for coupling to the antenna and a second connection point for coupling with at least one of said first and said second amplifiers and, wherein, in each of said filters, the first connection point is different from the second connection point;

a switch having at least two modes and serving to couple said apparatus to the antenna circuit;

wherein at least two of said filters, but not more than three of said filters, are essentially one and the same filter;

said switch is operative, in a first of the two modes, to couple the antenna circuit to a first set of said filters and, in a second of the two modes, to couple the antenna circuit to a second set of said filters, wherein, said first and said second filter sets collectively include all of said filters and, individually, each of said filter sets comprises at least one of said filters but not more than three of said filters; and

said first amplifier is connected to said first filter set, and said second amplifier is connected to said second filter set to enable communication of said first and said second signals via respective ones of said first and said second filters with said antenna circuit dependent on the first mode of said switch, and to enable communication of said third and said fourth signals via respective ones of said third and said fourth filters with said antenna circuit dependent on the second mode of said switch.

12. Apparatus, adapted for connection to an antenna, for transmitting and receiving RF signals, the apparatus enabling a transmission to take place at a first transmitter frequency band and at a second transmitter frequency band, said first and second transmitter frequency bands being separate, so that a reception can take place at a first receiver frequency band and at a second receiver frequency band, 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, a third, and a fourth filter of which at least one of said filters serves for filtering signals located in at least two different frequency bands;

a first amplifier for amplifying a first signal and a second signal after reception and filtering, and a second amplifier for amplifying a third signal and a fourth signal prior to filtering and transmission, wherein each of said filters has a first connection point for coupling to the antenna and a second connection point for coupling with at least one of said first and said second amplifiers and, wherein, in each of said filters, the first connection point is different from the second connection point;

a switch having at least two modes and serving to couple said filtering means, via the second connection points in respective ones of said filters, to said first and said second amplifiers;

wherein at least two of said filters, but not more than three of said filters, are essentially one and the same filter;

upon connection of the antenna circuit to said filtering means via the first connection points in respective ones of said filters, said switch is operative, in a first of the two modes, to couple said first amplifier to a first set of said filters and, in a second of the two modes, to couple said second amplifier to a second set of said filters, wherein, said first and said second filter sets collectively include all of said filters and, individually, each of said filter sets comprises at least one of said filters but not more than three of said filters; and

connection of said first amplifier to said first filter set, and connection of said second amplifier to said second filter set enables communication of said first and said second signals via respective ones of said first and said second filters with said antenna circuit dependent on the first mode of said switch, and enables communication of said third and said fourth signals via respective ones of said third and said fourth filters with said antenna circuit dependent on the second mode of said switch.