Abstract:
A signal transceiver for saving the production cost of a wireless communication device includes an antenna, an antenna switch module, a radio frequency (RF) transceiver, an RF front-end circuit, a first selection unit and a second selection unit. The signal transceiver uses the RF front-end circuit unit to meet requirements of multi-band for the wireless communication device through the operation of the first selection unit and the second selection unit to greatly reduce the production cost of the wireless communication device.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a signal transceiver of a wireless communication device and, more particularly, to a signal transceiver for saving the production cost of a wireless communication device. 
         [0003]    2. Description of the Related Art 
         [0004]    The wireless communication system rapidly develops recently, and the universal mobile telecommunications system (UMTS) replaces the global system for mobile communications (GSM) to be the mainstream wireless communication system. The wireless communication system utilizes different band in different country. Taking the GSM as an example, it utilizes the bands of 850 MHz and 1900 MHz in North America, and it utilizes the bands of 900 MHz and 1800 MHz in Europe. Taking the UMTS as an example, it utilizes the bands of 850 MHz and 1900 MHz in North America, and it utilizes the band of 2100 MHz in Europe. Since the wireless communication system utilizes different band in different country, when the wireless communication device is designed, in order to sell in different countries and reduce the production cost, a plurality of groups of radio frequency (RF) front-end circuits corresponding to different bands, respectively, are designed in the RF transceiver of the wireless communication device. 
         [0005]      FIG. 1  is a schematic diagram showing a conventional signal transceiver  10 . As shown in  FIG. 1 , the signal transceiver  10  includes a RF transceiver  100 , a first RF front-end circuit  102 , a second RF front-end circuit  104 , an antenna switch module (ASM)  106  and an antenna  108 . The RF transceiver  100  is coupled to the first RF front-end circuit  102  and the second RF front-end circuit  104  and includes a plurality of signal transmitting terminals and a plurality of signal receiving terminals, and it is used to modulate, demodulate, synthesize and mix a RF signal. The first RF front-end circuit  102  and the second RF front-end circuit  104  are coupled between the RF transceiver  100  and the ASM  106 , and they are two different circuits used in different bands and having components that are similar in function but different in standard. The first RF front-end circuit  102  and the second RF front-end circuit  104  are used to perform a filter function, a power amplifier function, a coupling function and a duplex function on the RF signal. The ASM  106  is coupled to the first RF front-end circuit  102 , the second RF front-end circuit  104  and the antenna  108  and includes a plurality of duplex transmission terminals. According to the operating band of the wireless communication device, one of the duplex transmission terminals of the ASM  106  is selected to couple to the antenna  108 . The antenna  108  is used to transmit or receive the RF signal. 
         [0006]    The first RF front-end circuit  102  and the second RF front-end circuit  104  are illustrated in detail herein below. Taking the first RF front-end circuit  102  as an example, it further includes a RF transmitter  120 , a RF receiver  122  and a duplexer  124 . The RF transmitter  120  includes a surface acoustic wave (SAW) filter, a power amplifier (PA), a coupler and an isolator and is used to process and transmit the RF signal. The RF receiver  122  includes a SAW filter and a low noise amplifier (LNA) and is used to receive and process the RF signal. The duplexer  124  is used to switch to transmit and receive the RF signal. The first RF front-end circuit  102  and the second RF front-end circuit  104  are two different groups of RF front-end circuit that are used under different bands. For example, if the wireless communication device using the signal transceiver  10  is intended to be sold to North America or Europe, the assembly of the first RF front-end circuit  102  is designed to operate under the band of 850 MHz, and the assembly of the second RF front-end circuit  104  is designed to operate under the band of 2100 MHz. The assemblies of the first RF front-end circuit  102  and the second RF front-end circuit  104  are pre-set on a circuit board, and the supplier of the wireless communication device can determine to use the assembly of the first RF front-end circuit  102  or the assembly of the second RF front-end circuit  104  according to the band used in different sales territory. 
         [0007]    Taking a mobile phone as an example, to meet the miniaturization and multi-function tendency, the area of circuit layout becomes smaller and smaller, and the production cost becomes higher and higher. Since the cost of the assembly of the RF front-end circuit is high, the mode of pre-setting a plurality of groups of RF front-end circuit cannot reduce the area of circuit layout and the volume of the product, wastes the production cost and cannot make the product maintain the competitive power on the market. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The objective of the invention is to provide a signal transceiver for saving the cost of a wireless communication device. 
         [0009]    The invention discloses a signal transceiver for a wireless communication device and for saving the area of circuit layout and reducing the cost. The signal transceiver includes an antenna, an antenna switch module (ASM), a radio frequency (RF) transceiver, a RF front-end circuit, a first selection unit and a second selection unit. The ASM is coupled to the antenna and includes a plurality of duplex transmission terminals. The RF transceiver includes a plurality of signal transmitting terminals and a plurality of signal receiving terminals and is used to generate or process a RF signal via the signal transmitting terminals and the signal receiving terminals. The RF front-end circuit is used to process the RF signal. A first selection unit coupled between the RF transceiver and the RF front-end circuit and used to select a signal transmitting terminal from the signal transmitting terminals and a signal receiving terminal from the signal receiving terminals to couple to the RF front-end circuit according to the operating band of the wireless communication device; and a second selection unit coupled between the RF front-end circuit and the ASM and used to select one duplex transmission terminal from the duplex transmission terminals to couple to the RF front-end circuit according to the operating band of the wireless communication device. 
         [0010]    The invention further discloses a signal transceiver for a wireless communication device and for saving the area of circuit layout and reducing the cost. The signal transceiver includes an antenna module, a RF transceiver, a RF front-end circuit and a selection unit. The RF transceiver includes a plurality of signal transmitting terminals and a plurality of signal receiving terminals and is used to generate or process a RF signal via the signal transmitting terminals and the signal receiving terminals. The RF front-end circuit is coupled to the antenna module and used to process the RF signal. A selection unit coupled between the RF transceiver and the RF front-end circuit and used to select a signal transmitting terminal from the signal transmitting terminals and a signal receiving terminal from the signal receiving terminals to couple to the RF front-end circuit according to the operating band of the wireless communication device. 
         [0011]    The invention further discloses a signal transceiver for a wireless communication device and for saving the area of circuit layout and reducing the cost. The signal transceiver includes an antenna module, a RF transceiver, a RF front-end circuit and a selection unit. The RF transceiver includes a plurality of signal transmitting terminals and a plurality of signal receiving terminals and is used to generate or process a RF signal via the signal transmitting terminals and the signal receiving terminals. The RF front-end circuit is used to process the RF signal. The selection unit is coupled between the antenna module and the RF front-end circuit and used to select a duplex transmission terminal from the duplex transmission terminals of the antenna module to couple the duplex transmission terminal to the RF front-end circuit according to the operating band of the wireless communication device. 
         [0012]    In the invention, the RF front-end circuit meets requirements of a plurality of operating bands for the wireless communication device to greatly reduce the production cost of the wireless communication device. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0013]      FIG. 1  is a schematic diagram showing a conventional signal transceiver; and 
           [0014]      FIG. 2  is a schematic diagram showing a signal transceiver of an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0015]    As shown in  FIG. 2 ,  FIG. 2  is a schematic diagram showing a signal transceiver  20  for a wireless communication device in an embodiment of the invention. The wireless communication device may be a mobile phone or other electronic device having a wireless communication function. The signal transceiver  20  is used to transmit or receive a radio frequency (RF) signal corresponding to the wireless communication device. For example, the signal transceiver  20  converts a baseband signal to a RF signal and emit the RF signal to the air, or it converts a received RF signal to a baseband signal. The signal transceiver  20  includes an antenna  202 , an antenna switch module (ASM)  204 , a RF transceiver  206 , a RF front-end circuit  208 , a first selection unit  210  and a second selection unit  212 . 
         [0016]    The antenna  202  is coupled to the ASM  204  and used to transmit or receive a RF signal. The ASM  204  is coupled between the antenna  202  and the second selection unit  212  and includes duplex transmission terminals  2040  and  2042 . The ASM  204  is used to select one duplex transmission terminal from the duplex transmission terminals  2040  and  2042  to couple to the antenna  202  according to the operating band of the wireless communication device. The RF transceiver  206  is coupled to the first selection unit  210  and includes signal transmitting terminals  2060  and  2062  and signal receiving terminals  2064  and  2066 . The RF transceiver  206  is used to modulate, demodulate, synthesize and mix the RF signal. The RF front-end circuit  208  is coupled between the first selection unit  210  and the second selection unit  212  and includes a first signal transmitting terminal  220 , a first signal receiving terminal  230 , a duplex transmission terminal  240  and other components (illustrated hereinbelow), and it is used to perform a filter function, a power amplifier function, a coupling function and a duplex function on the RF signal. The first selection unit  210  is coupled between the RF transceiver  206  and the RF front-end circuit  208  and includes transmitting switch assemblies  2100  and  2102  and receiving switch assemblies  2104  and  2106 . The transmitting switch assemblies  2100  and  2102  are coupled between the signal transmitting terminals  2060  and  2062  and the first signal transmitting terminal  220  and used to set the conduction condition between the corresponding signal transmitting terminal and the first signal transmitting terminal  220  according to the operating band of the wireless communication device. The receiving switch assemblies  2104  and  2106  are coupled between the signal receiving terminals  2064  and  2066  and the first signal receiving terminal  230 , respectively, and used to set the conduction condition between the corresponding signal receiving terminal and the first signal receiving terminal  230  according to the operating band of the wireless communication device. The second selection unit  212  is coupled between the antenna module  204  and the RF front-end circuit  208  and includes switch assemblies  2120  and  2122 . The switch assemblies  2120  and  2122  are coupled between the duplex transmission terminals  2040  and  2042  and the duplex transmission terminal  240 , respectively and used to set the conduction condition between the corresponding duplex transmission terminal and the duplex transmission terminal  240  according to the operating band of the wireless communication device. 
         [0017]    The RF front-end circuit  208  is illustrated in detail. The RF front-end circuit  208  includes a duplexer  250 , a RF transmitter  260  and a RF receiver  270  besides the first signal transmitting terminal  220 , the first signal receiving terminal  230  and the duplex transmission terminal  240 . The duplexer  250  is coupled between the RF transmitter  260  and the RF receiver  270  and the duplex transmission terminal  240  and used to switch to transmit or receive the RF signal. The RF transmitter  260  is coupled between the first signal transmitting terminal  220  and a duplexer  250  and used to perform a filter function, a power amplifier function and a coupling function on the RF signal. The RF receiver  270  is coupled between the first signal receiving terminal  230  and the duplexer  250  and used to perform a filter function and a power amplifier function on the RF signal. 
         [0018]    The first selection unit  210  can select one signal transmitting terminal from the signal transmitting terminals  2060  and  2062  of the RF transceiver  206  to couple the signal transmitting terminal to the first signal transmitting terminal  220  of the RF front-end circuit  208  and select one signal receiving terminal from the signal receiving terminals  2064  and  2066  of the RF transceiver  206  to couple the signal receiving terminal to the first signal receiving terminal  230  of the RF front-end circuit  208  according to the operating band of the wireless communication device. The second selection unit  212  can select one duplex transmission terminal from the duplex transmission terminals  2040  and  2042  of the ASM  204  to couple the duplex transmission terminal to the duplex transmission terminal  240  of the RF front-end circuit  208  according to the operating band of the wireless communication device. In other words, the signal transceiver  20  only needs to include one group of RF front-end circuit (namely, the RF front-end circuit  208 ), and it can transmit or receive the RF signal of different operating bands via the switch of the first selection unit  210  and the second selection unit  212 . For example, if the wireless communication device using the signal transceiver  20  is intended to be sold to North America, the assemblies of the RF front-end circuit  208  can be designed to operate under the operating band of 850 MHz, or if the wireless communication device using the signal transceiver  20  is intended to be sold to Europe, the assemblies of the RF front-end circuit  208  can be designed to operate under the operating band of 2100 MHz. 
         [0019]      FIG. 2  is a schematic diagram showing the signal transceiver  20  of the embodiment of the invention, and persons having ordinary skill in the art can make modification without departing the spirit of the invention. For example, the designer may select to use the first selection unit  210  or the second selection unit  212  only according to a requirement. If only the first selection unit  210  is used, the duplex transmission terminal  240  of the RF front-end circuit  208  is coupled to the duplex transmission terminals  2040  and  2042  of the ASM  204 . If only the second selection unit  212  is used, the first signal transmitting terminal  220  of the RF front-end circuit  208  is coupled to the signal transmitting terminals  2060  and  2062  of the RF transceiver  206 , and the first signal receiving terminal  230  is coupled to the signal receiving terminals  2064  and  2066  of the RF transceiver  206 . 
         [0020]    The numbers of the signal transmitting terminals and the signal receiving terminals of the RF transceiver  206  may be changed according to the requirement of the designer, and they are not limited in the invention. The number of the duplex transmission terminals of the ASM  204  also may be changed. Under this condition, the numbers of the switch assemblies of the first selection unit  210  and the second selection unit  212  also can be changed. In  FIG. 2 , the RF front-end circuit  208  is used to transmit or receive the RF signal, and it can be changed according to the requirement of the designer and is not limited in the invention. In the embodiment of the invention, the signal transceiver  20  can be used under two different bands via the switch of the first selection unit  210  and the second selection unit  212 . If the RF transceiver  206  includes three signal transmitting terminals and three signal receiving terminal, and the ASM  204  also includes three duplex transmission terminals, the signal transceiver  20  can be used under three different bands via the switch of the first selection unit  210  and the second selection unit  212 , and the rest may be deduced by analogy. 
         [0021]    From the above, only the circuit layout and component positions of one group of RF front-end circuit (namely, the RF front-end circuit  208 ) need to be kept, and the wireless communication device still can be used in different country or area via the switch of the first selection unit  210  and the second selection unit  212  according to the operating band used in different sales territory. Therefore, the embodiment of the invention overcomes faults that the area of circuit layer, the production volume and the production cost cannot be reduced in the conventional technology that a plurality of groups of RF front-end circuit should be designed. 
         [0022]    To sum up, in the embodiment of the invention, the first selection unit  210  and the second selection unit  212  are switched to allow the RF front-end circuit  208  to use different assemblies to transmit or receive the RF signals of different bands according to the operating band of the wireless communication device, thereby reducing the area of circuit layout and the production volume and saving the production cost. 
         [0023]    Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, the disclosure is not for limiting the scope of the invention. Persons having ordinary skill in the art may make various modifications and changes without departing from the scope and spirit of the invention. Therefore, the scope of the appended claims should not be limited to the description of the preferred embodiments described above.