Antenna duplexer and wireless terminal using the same
a wireless terminal and duplexing technology, applied in the field of duplexing, can solve the problems of increasing difficulty in operation of such devices, and achieve the effect of reducing the size and the number of switches
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first embodiment
[0042]FIG. 2 shows an example of the first embodiment of the present invention. An example of the RF circuit for antenna duplexer assumed to be used for the quad-band terminal is shown in FIG. 2. By the adoption of this RF circuit, it becomes possible to pair the transmitting and receiving frequencies of each system and to handle the bands corresponding to four systems of the respective frequencies of EGSM, DCS, PCS and GSM 850 with a single antenna.
[0043] First, the configuration of the wireless terminal will be described in brief with using the quad-band terminal as an example. FIG. 10 is a simplified block diagram showing the wireless terminal. Since it handles the RF signals of both 824 to 960 MHz band and 1.71 to 1.99 GHz band, the circuit is generally large and complicated. Various types of new circuit systems have been proposed for the size reduction of the terminal. In the OPLL (Offset Phase Lock Loop) modulation method adopted in the transmitter system, the modulation is d...
second embodiment
[0057] Subsequently, FIG. 3 and FIG. 4 shown an example of the 15 second embodiment of the present invention. This configuration is common to the RF circuit for multiband switch-type antenna duplexer such as dual band, triple band and quad band and more. In general, the number of RF-IC pins is increased with the development of the multiband operation, and it is expected that the problem of the number of pins will become severer in the future. An object of the configuration of this proposal is to solve the problem.
[0058] The RF circuit with the configuration of this embodiment is effective for the system in which fT(1)2) is satisfied and fR(1) partially overlaps fT(2) when the transmitting and receiving frequency bands of the first system are denoted as fT(1) and fR(1) and the transmitting and receiving frequency bands of the second system are denoted as fT(2) and fR(2).
[0059] In FIG. 3, the first system is, for example, the GSM 850 and the second system is, for example, the EGSM. ...
third embodiment
[0066] Subsequently, FIG. 5 to FIG. 7 show an example of the third embodiment of the present invention. In the circuit in FIG. 5, a balun circuit 30 is introduced between the third parallel connection point 5 and the common terminal for reception in the circuit of FIG. 3 or FIG. 4 (example of using the circuit of FIG. 3 is shown in FIG. 5), so that the common output terminal for reception is changed to the differential output terminal. By doing so, since not only the number of receiving terminals but also the number of balun circuits can be reduced, the simplification of the entire circuit and the cost reduction can be achieved. FIG. 6 shows a concrete example of an embodiment including the balun circuit of FIG. 5. More specifically, the balun circuit is formed of the circuit composed of the serial arm inductance and the parallel arm capacitance from the side of the parallel connection point 5 between the third parallel connection point 5 and one of the differential output terminals...
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