Receiver/transmitter capable of simultaneously receiving/transmitting discontinuous frequency signals and method thereof

1. Field of the Invention

The present invention relates to a signal processing scheme, and more particularly to a receiver and a transmitter capable of simultaneously receiving and transmitting discontinuous frequency band signal components of an input signal and methods thereof.

2. Description of the Prior Art

Generally speaking, a conventional transceiver configuration mainly comprises a direction conversion transceiver configuration and a two-step conversion transceiver configuration. For example, U.S. Pat. No. 5,878,332 disclosed a transceiver implemented with two antennas wherein one antenna is used for receiving and transmitting signals of a band and the other antenna is used for receiving and transmitting signals of another band. Band pass filters are further employed by U.S. Pat. No. 5,878,332 for receiving and transmitting signals of the two different bands, respectively. A drawback of the transceiver provided by U.S. Pat. No. 5,878,332 is that such transceiver is not able to simultaneously receive the signals of the two different bands and is not able to simultaneously transmit the signals of the two different bands. Further, U.S. Pat. No. 7,613,430 disclosed a transceiver which performs two-step down-conversion upon a received signal and appropriately selects frequencies of two different synthesizers to avoid affection of disturbing signal components, by using a radio-frequency (RF) synthesizer and an intermediate frequency (IF) synthesizer. However, such transceiver provided by U.S. Pat. No. 7,613,430 is merely used for receiving/transmitting continuous frequency band signals but cannot be utilized for receiving and transmitting signals with discontinuous frequency bands. Moreover, U.S. Pat. No. 7,266,352 disclosed using three different local oscillation frequency signals to respectively perform down-conversion upon three different frequency band signals (802.11b/g, 802.11a (low band)/j, and 802.11a (high band)) and using another local oscillation frequency signal to down-convert these down-converted signals into baseband domain. U.S. Pat. No. 7,266,352 disclosed using a similar signal transmission scheme to perform two-step up-conversion to obtain three different frequency band signals. However, this reception/transmission circuit configuration cannot simultaneously process discontinuous frequency band signals at the same time.

As a result, it is necessary for the above-mentioned transceivers to receive discontinuous frequency band signals at different and separate timings and to transmit/emit discontinuous frequency band signals at different and separate timings.

It is therefore one of the objectives of the present invention to provide a receiver and corresponding method for simultaneously receiving discontinuous frequency band signal components of an input signal at the same time, and to provide a transmitter and corresponding method for simultaneously transmitting discontinuous frequency band signal components of an output signal at the same time, so as to solve the described-above problems.

According to an embodiment of the present invention, a receiver capable of simultaneously receiving discontinuous frequency band signal components of an input signal at the same time is disclosed. The receiver comprises a frequency synthesizer and a down-conversion circuit. The frequency synthesizer is used for generating an in-phase local oscillation differential signal and a quadrature-phase local oscillation differential signal. The down-conversion circuit is coupled to the frequency synthesizer, and utilized for performing frequency down-conversion upon the input signal to generate a first down-converted signal by using the in-phase local oscillation differential signal and the quadrature-phase local oscillation differential signal, and performing the frequency down-conversion upon the input signal to generate a second down-converted signal by using the in-phase local and quadrature-phase oscillation differential signals that have been phase-swapped.

According to an embodiment of the present invention, a method capable of simultaneously receiving discontinuous frequency band signal components of an input signal is disclosed. The method comprises: providing an in-phase local oscillation differential signal and a quadrature-phase local oscillation differential signal; performing frequency down-conversion upon the input signal to generate a first down-converted signal by utilizing the in-phase and quadrature-phase local oscillation differential signals; and performing the frequency down-conversion upon the input signal to generate a second down-converted signal by using the in-phase local and quadrature-phase oscillation differential signals that have been phase-swapped.

According to an embodiment of the present invention, a transmitter capable of simultaneously transmitting discontinuous frequency band signal components of an output signal is disclosed. The transmitter comprises a frequency synthesizer and an up-conversion circuit. The frequency synthesizer is utilized for generating an in-phase local oscillation differential signal and a quadrature-phase local oscillation differential signal. The up-conversion circuit is coupled to the frequency synthesizer, and utilized for performing frequency up-conversion upon a first transmitted signal to generate a first up-converted signal by utilizing the in-phase local oscillation differential signal and the quadrature-phase local oscillation differential signal, and performing the frequency up-conversion upon a second transmitted signal to generate a second up-converted signal by utilizing the in-phase local oscillation differential signal and the quadrature-phase local oscillation differential signal that have been phase swapped. The first and second up-converted signals respectively correspond to the discontinuous frequency band signal components in the output signal.

According to an embodiment of the present invention, a method capable of simultaneously transmitting discontinuous frequency band signal components of an output signal is disclosed. The method comprises: providing an in-phase local oscillation differential signal and a quadrature-phase local oscillation differential signal; performing frequency up-conversion upon a first transmitted signal to generate a first up-converted signal by utilizing the in-phase local oscillation differential signal and the quadrature-phase local oscillation differential signal; and performing the frequency up-conversion upon a second transmitted signal to generate a second up-converted signal by utilizing the in-phase local oscillation differential signal and the quadrature-phase local oscillation differential signal that have been phase swapped; wherein the first and second up-converted signals respectively correspond to the discontinuous frequency band signal components in the output signal.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

FIG. 1 is a diagram illustrating a receiver according to a first embodiment of the present invention.

FIG. 2A is a circuitry diagram of a radio-frequency input stage and an intermediate frequency output stage of the first down-conversion unit in the down-conversion circuit as shown in FIG. 1 .

FIG. 2B is a circuitry diagram of a radio-frequency input stage and an intermediate frequency output stage of the second down-conversion unit in the down-conversion circuit as shown in FIG. 1 .

FIG. 3 is a diagram illustrating a transmitter according to a second embodiment of the present invention.

FIGS. 4A-4B are diagrams illustrating operation flows of the receiver as shown in FIG. 1 .

FIGS. 5A-5B are diagrams illustrating operation flows of the transmitter as shown in FIG. 3 .

Please refer to FIG. 1 , which is a diagram illustrating a receiver 100 according to a first embodiment of the present invention. The receiver 100 comprises an antenna 105 , a low noise amplifier 110 , a frequency synthesizer 115 , a down-conversion circuit 120 , and a processing circuit 125 . The input radio-frequency (RF) signal S_RF comprises discontinuous frequency band signal components including a first frequency band and a second frequency band. In this embodiment, the RF signal S_RF comprises a first frequency band signal component having a center frequency F C that is indicated by slash lines of FIG. 1 and a second frequency band signal component having a center frequency F C +N*W that is indicated by dots of FIG. 1 . The value N is an integer that is greater than or equal to 2, and the value W indicates the bandwidth of the first and second frequency bands. For example, the bandwidth is 80 MHz. In another embodiment, the input signal can be represented by a differential signal and comprises a positive terminal signal RF + and a negative terminal signal RF − , as shown in FIG. 2A and FIG. 2B .

In this embodiment, the RF signal S_RF is transmitted to the low noise amplifier 110 via the antenna 105 , and the low noise amplifier 110 effectively attenuates noise of the RF signal S_RF and amplifies the signal components of the RF signal S_RF, to increase the signal-to-noise (SNR) of the RF signal S_RF. The down-conversion circuit 120 is arranged to perform two-way down-conversion upon the RF signal S_RF to generate the first down-converted signal S_IF 1 and the second down-converted signal S_IF 2 . The down-converted signals S_IF 1 and S_IF 2 are intermediate frequency (IF) signals and respectively represented by differential signals as shown in FIG. 2A and FIG. 2B . The down-conversion circuit 120 comprises RF IQ mixers 1201 A and 1201 B that are arranged to respectively receive oscillation signals LOI_ 1 and LOQ_ 1 provided by the frequency synthesizer 115 . The first down-converted signal S_IF 1 is used for separating a frequency band signal having a center frequency F C included within the RF signal S_RF. The second down-converted signal S_IF 2 is used for separating a frequency band signal having a center frequency F C +N*W included within the RF signal S_RF. In addition, the above-mentioned two-way down-conversion is performed based on in-phase and quadrature-phase signals of the same local oscillation frequency, and the only difference is that the in-phase and quadrature-phase local oscillation signals are phase swapped in one branch of the two-way down-conversion. The two-way down-conversion can therefore regarded as the same down-conversion processing operation used for respectively generating the first down-converted signal S_IF 1 and the second down-converted signal S_IF 2 . Accordingly, by employing the circuitry structure of the down-conversion circuit 120 , it is able to simultaneously receive, retrieve, or process two discontinuous frequency band signal components during the same down-conversion processing operation by merely swapping phases of the in-phase and quadrature-phase local oscillation signals.

The output frequency of the frequency synthesizer 115 is referenced/adopted by the down-conversion circuit 120 and used as the local oscillation frequency. For the frequency synthesizer 115 , in order to appropriately separate two discontinuous frequency band signals, the oscillation frequency is determined and located at the center between the two center frequencies of two discontinuous frequency band signals. For example, the center frequencies of two discontinuous frequency band signals in the RF signal S_RF are F C and F C +N*W respectively, and the oscillation frequency of the frequency synthesizer 115 is selected as F C +(N/2)*W. The oscillation output signals generated by the frequency synthesizer 115 are respectively the in-phase local oscillation differential signal LOI_ 1 and the quadrature-phase local oscillation differential signal LOQ_ 1 wherein the in-phase local oscillation differential signal LOI_ 1 includes the positive terminal signal LOI + and negative terminal signal LOI − as shown in FIG. 2A and FIG. 2B and the quadrature-phase local oscillation differential signal LOQ_ 1 includes the positive terminal signal LOQ + and negative terminal signal LOQ − as shown in FIG. 2A and FIG. 2B . The in-phase and quadrature-phase local oscillation differential signals LOI_ 1 and LOQ_ 1 are respectively inputted into the first and second down-conversion units 1201 A and 1201 B of the down-conversion circuit 120 . The first down-conversion unit 1201 A refers to the in-phase positive and negative terminal signals LOI + and LOI − and the quadrature-phase positive and negative terminal signals LOQ + and LOQ − to generate the first down-converted signal S_IF 1 . In addition, when generating the second down-converted signal S_IF 2 , the down-conversion circuit 120 performs phase swapping upon the positive and negative terminal signals of one of the in-phase and quadrature-phase local oscillation differentials LOI_ 1 and LOQ_ 1 to obtain the in-phase and quadrature-phase local oscillation differentials LOI_ 1 and LOQ_ 1 that are phase swapped. Thereafter, the down-conversion circuit 120 performs down-conversion operation upon the input RF signal S_RF based on the in-phase and quadrature-phase local oscillation differentials LOI_ 1 and LOQ_ 1 that have been phase swapped, so as to generate the second down-converted signal S_IF 2 . In practice, the in-phase positive and negative terminal signals LOI + and LOI − and the quadrature-phase positive and negative terminal signals LOQ + and LOQ − are also inputted to the second down-conversion unit 1201 B. Accordingly, the second down-conversion unit 1201 B generates the second down-converted signal S_IF 2 by referring to the in-phase positive and negative terminal signals LOI + and LOI − and the quadrature-phase positive and negative terminal signals LOQ + and LOQ − . In detail, the circuitry configuration for connecting the signals LOI + , LOI − , LOQ + , and LOQ − to the first down-conversion unit 1201 A is different from the circuitry configuration for connecting the signals LOI + , LOI − , LOQ + , and LOQ − to the second down-conversion unit 1201 B, and phase swapping operation is achieved.

Please refer to FIG. 2A in conjunction with FIG. 2B . FIG. 2A and FIG. 2B are diagrams illustrating RF input stages and IF output stages of the first and second down-conversion units 1201 A and 1201 B included within the down-conversion circuit 120 as shown in FIG. 1 , respectively. The RF input stage of the first down-conversion unit 1201 A is composed by two different sets of transistor differential pairs, and is used for receiving the differential input signal S_RF including signals RF + and RF − . The IF output stage of the first down-conversion unit 1201 A includes an in-phase IF output stage and a quadrature-phase IF output stage. The in-phase IF output stage is comprised by four transistor switches Q 1 -Q 4 and used for receiving the in-phase positive and negative terminal signals LOI + and LOI − , controlling these transistor switches Q 1 -Q 4 by referring to the signals LOI + and LOI − so as to perform down-conversion upon the input differential signal S_RF for generating the in-phase positive and negative terminal down-converted signals SOI + and SOI − . The in-phase signal components of the first down-converted signal S_IF 1 are formed by the in-phase positive and negative terminal down-converted signals SOI + and SOI − . The quadrature-phase IF output stage is comprised by four transistor switches Q 5 -Q 8 and utilized for receiving the quadrature-phase positive and negative terminal signals LOQ + and LOQ − , controlling these transistor switches Q 5 -Q 8 by referring to the signals LOQ + and LOQ − so as to perform down-conversion upon the input differential signal S_RF for generating the in-phase positive and negative terminal down-converted signals SOQ + and SOQ − . The quadrature-phase signal components of the first down-converted signal S_IF 1 are formed by the quadrature-phase positive and negative terminal down-converted signals SOQ + and SOQ − . In other words, the first down-converted signal S_IF 1 is formed by these signals SOI + , SOI − , SOQ + , and SOQ − that are outputted by the first down-conversion unit 1201 A as shown in FIG. 2A .

For the second down-conversion unit 1201 B, the RF input stage of the second down-conversion unit 1201 B is composed by two different sets of transistor differential pairs, and is used for receiving the differential input signal S_RF including signals RF + and RF − . The IF output stage of the second down-conversion unit 1201 B includes an in-phase IF output stage and a quadrature-phase IF output stage. The in-phase IF output stage is comprised by four transistor switches Q 9 -Q 12 and used for receiving the in-phase positive and negative terminal signals LOI + and LOI − , controlling these transistor switches Q 9 -Q 12 by referring to the signals LOI + and LOI − so as to perform down-conversion upon the input differential signal S_RF for generating the in-phase positive and negative terminal down-converted signals SOI + and SOI − . The in-phase signal components of the second down-converted signal S_IF 2 are formed by the in-phase positive and negative terminal down-converted signals SOI + and SOI − . The quadrature-phase IF output stage is comprised by four transistor switches Q 13 -Q 16 and utilized for receiving the quadrature-phase positive and negative terminal signals LOQ + and LOQ − , controlling these transistor switches Q 13 -Q 16 by referring to the signals LOQ + and LOQ − so as to perform down-conversion upon the input differential signal S_RF for generating the in-phase positive and negative terminal down-converted signals SOQ + and SOQ − . The quadrature-phase signal components of the second down-converted signal S_IF 2 are formed by the quadrature-phase positive and negative terminal down-converted signals SOQ + and SOQ − . In other words, the second down-converted signal S_IF 2 is formed by these signals SOI + , SOI − , SOQ + , and SOQ − that are outputted by the second down-conversion unit 1201 B as shown in FIG. 2B .

It should be noted that the quadrature-phase positive and negative terminal signals LOQ + and LOQ − are respectively coupled to the corresponding nodes/terminals of the quadrature-phase IF output stage in the first down-converted unit 1201 A. For example, the positive terminal LOQ + is coupled to the control terminals of transistor switch Q 5 and Q 8 , and the negative terminal signal LOQ − is coupled to the control terminals of transistor switch Q 6 and Q 7 . For the quadrature-phase IF output stage in the second down-converted unit 1201 B, a difference is that the corresponding nodes/terminals that are coupled to the signals LOQ + and LOQ − are exchanged. For example, the positive terminal signal LOQ + is coupled to control terminals of the transistor switches Q 14 and Q 15 , and the negative terminal signal LOQ − is coupled to control terminals of the transistor switches Q 13 and Q 16 . This circuitry configuration is used to achieve performing phase swapping upon the input signal. However, this is one of embodiments of phase swapping and merely used for illustrative purposes. This embodiment is not intended to be a limitation of the present invention. Additionally, in another embodiment, performing phase swapping upon the input signal can be achieved by exchanging the corresponding nodes/terminals that are coupled to the in-phase positive and negative terminal signals LOI + and LOI − . That is, in the down-conversion circuit 120 , the positive and negative differential signals LOQ + and LOQ − of the quadrature-phase local oscillation differential signal LOQ can be exchanged to achieve phase swapping operation; In addition, the positive and negative differential signals LOI + and LOI − of the in-phase local oscillation differential signal LOI can be exchanged to achieve phase swapping operation. These modifications all fall within the scope of the present invention.

Please refer to FIG. 1 again. The first down-converted signal S_IF 1 mentioned above is an IF lower sideband signal, and the second down-converted signal S_IF 2 is an IF upper sideband signal. As shown in FIG. 1 , the first down-converted signal S_IF 1 includes signal components (as illustrated by backslash lines) having a center frequency (N/2)*W and signal components (as illustrated by dots) having a center frequency (−N/2)*W; the intensities of signal components as illustrated by dots are suppressed. In addition, the second down-converted signal S_IF 2 includes signal components (as illustrated by dots) having a center frequency (N/2)*W and signal components (as illustrated by backslash lines) having a center frequency (−N/2)*W; the intensities of signal components as illustrated by backslash lines are suppressed. As a result, in addition to effectively separating two discontinuous frequency ban signals, the down-conversion circuit 120 can appropriately perform signal intensity suppression upon undesired frequency band signal components. Accordingly, the baseband signal can easily be obtained by merely performing simple IF-to-baseband conversion operation. As shown in FIG. 1 , the processing circuit 125 comprises mixers 1251 A and 1251 B, a frequency synthesizer 1252 , filters 1253 A- 1253 D, and gain amplifiers 1254 A- 1254 D. The frequency synthesizer 1252 adopts the local oscillation frequency (N/2)*W and generates the in-phase and quadrature-phase local oscillation differential signals LOI_ 2 and LOQ_ 2 accordingly. The in-phase and quadrature-phase local oscillation differential signals LOI_ 2 and LOQ_ 2 are outputted by the frequency synthesizer 1252 to the mixers 1251 A- 1251 B. The mixer 1251 A can consequently convert the IF lower sideband signal (i.e. the first down-converted signal S_IF 1 ) into a baseband signal by referring to the in-phase and quadrature-phase local oscillation differential signals LOI_ 2 and LOQ_ 2 , so as to generate the first received signal S_B 1 (i.e. the baseband signal). Similarly, the mixer 1251 B can converts the IF upper sideband signal (i.e. the second down-converted signal S_IF 2 ) into a baseband signal by referring to the in-phase and quadrature-phase local oscillation differential signals LOI_ 2 and LOQ_ 2 , so as to generate the second received signal S_B 2 (i.e. the baseband signal). Thereafter, the in-phase and quadrature-phase signal components of the baseband signal S_B 1 can be processed by the filters 1253 A and 1253 B and the gain amplifiers 1254 A and 1254 B, respectively. Similarly, the in-phase and quadrature-phase signal components of the baseband signal S_B 2 are processed by filters 1253 C and 1253 D and gain amplifiers 1254 C and 1254 D, respectively. As a result, undesired disturbing signal sources can be filtered out. In addition, in order to achieve better suppression for image frequency signal components, a mixer configuration having a higher image rejection ratio (IRR) can be employed to implement the first and second down-conversion units 1201 A and 1201 B and the mixers 1251 A and 1251 B.

Please refer to FIG. 3 , which is a diagram of a transmitter 300 capable of simultaneously transmitting discontinuous frequency band signals at the same time according to a second embodiment of the present invention. The transmitter 300 comprises an antenna 305 , a power amplifier 310 A, a driving amplifier 310 B, a frequency synthesizer 315 , an up-conversion circuit 320 , and a processing circuit 325 . The up-conversion circuit 320 includes first and second up-conversion units 3201 A and 3201 B, and the processing circuit 325 includes mixers 3251 A- 3251 B and filters 3253 A- 3253 D. The transmitter 300 is utilized for simultaneously processing and transmitting the discontinuous frequency band signals included within the RF signal S_RF. As shown in FIG. 3 , the transmitter 300 is arranged to carry and transmit two different baseband signals S_B 1 and S_B 2 to the air via two discontinuous frequency bands having different center frequencies. The signal S_B 1 is a baseband lower sideband signal, and the signal S_B 2 is a baseband upper sideband signal. In-phase and quadrature-phase signal components of the baseband signal S_B 1 are processed by low-pass filters 3253 A and 3253 B, respectively, to reduce undesired disturbing noise, and the processed baseband signal S_B 1 is converted to an intermediate frequency (IF) signal by the mixer 3251 A to generate a first transmitted signal SIF_ 3 (i.e. the IF signal). Similarly, the baseband signal S_B 2 is converted to an IF signal by the mixer 3251 B to generate a second transmitted signal SIF_ 4 (i.e. the IF signal). The local oscillation frequency adopted by the mixers 3251 A and 3251 B is generated by the frequency synthesizer 3252 and is equal to (N/2)*W. The value N is greater than or equal to an integer 2, and can be configured by designers. The value W is the bandwidth size of the baseband signals S_B 1 and S_B 2 .

The frequency synthesizer 3252 is used for generating the in-phase local oscillation signal LOI_ 2 and quadrature-phase local oscillation signal LOQ_ 2 according to the oscillation frequency (N/2)*W. The signals LOI_ 2 and LOQ_ 2 are outputted to the mixers 3251 A and 3251 B, respectively, and the mixers 3251 A and 3251 B can therefore perform up-conversion upon the baseband signals S_B 1 and S_B 2 respectively according to the oscillation frequency (N/2)*W so as to generate IF signals SIF_ 3 and SIF_ 4 . The center frequencies of IF signals SIF_ 3 and SIF_ 4 are located at (N/2)*W. Thereafter, the first up-conversion unit 3201 A receives the IF signal SIF_ 3 and converts the IF signal SIF_ 3 to the RF domain by referring to the local oscillation frequency signal generated by the frequency synthesizer 315 , for generating a first up-converted signal. Similarly, the second up-conversion unit 3201 B receives the IF signal S_IF 4 and converts the IF signal S_IF 4 to the RF domain by referring to the local oscillation frequency signal generated by the frequency synthesizer 315 , for generating a second up-converted signal. In order to respectively convert two groups of desired signal components to a higher frequency domain so as to make the center frequencies be equal to F C and F C +N*W, the frequency synthesizer 315 is arranged to generate an oscillation frequency signal having a frequency equal to F C +(N/2)*W. In detail, signal components as illustrated by backslash lines are converted to a higher frequency domain, and the center frequency is located at F C . In addition, signal components as illustrated by dots are converted to a higher frequency domain, and the center frequency is located at F C +N*W. Accordingly, the frequency synthesizer 315 is arranged to generate the in-phase local oscillation signal LOI_ 1 and the quadrature-phase local oscillation signal LOQ_ 1 into the first and second up-conversion units 3201 A and 3201 B respectively. As a result, the first up-conversion unit 3201 A is arranged to convert the IF signal SIF_ 3 into the RF domain according to the in-phase and quadrature-phase local oscillation frequency signals LOI_ 1 and LOQ_ 1 having an oscillation frequency F C +(N/2)*W so that the center frequency of the up-converted signal components is located at F C . Similarly, the second up-conversion unit 3201 B is arranged to convert the IF signal SIF_ 4 into the RF domain according to the in-phase and quadrature-phase local oscillation frequency signals LOI_ 1 and LOQ_ 1 having an oscillation frequency F C +(N/2)*W so that the center frequency of the up-converted signal components is located at F C +N*W. Some image frequency signals may be generated due to up-conversion mentioned above. For example, some image signal components are generated at F C +N*W when the first up-conversion unit 3201 A converts the IF signal SIF_ 3 to a higher frequency domain to make the up-converted signal components have a center frequency F C . Although some image signals are introduced, using a circuit element having a higher IRR to implement the first up-conversion unit 3201 A can achieve significant suppression for the generated image signal components. Consequently, normal/desired signal components are not affected by these image signal components. Similarly, using a circuit element having a higher IRR to implement the second up-conversion unit 3201 B can achieve significant suppression for the generated image signal components, and normal/desired signal components are not affected by these image signal components.

By operations of the first and second up-conversion units 3201 A and 3201 B, the signal components as illustrated by backslash lines can be up-converted to a frequency band having the center frequency F C , and the signal components as illustrated by dots can be up-converted to a frequency band having the center frequency F C +N*W. Since the value N is greater than or equal to the positive integer 2 and the bandwidth of the backslash line signal components or dot signal components is equal to W, the backslash line signal components and dot signal components are carried in the two discontinuous frequency bands of the RF signal S_RF and emitted from the antenna 305 after processed by the driving amplifier 310 B and power amplifier 310 A. The backslash line signal components are carried and located at a frequency band having a center frequency F C , and the dot signal components are carried and located at a frequency band having a center frequency F C +N*W. The up-conversions of the first and second up-conversion units 3201 A and 3201 B are associated with the in-phase and quadrature-phase signals of the same local oscillation frequency, and a difference is that the in-phase and quadrature-phase signals components are phase swapped in one up-conversion unit while the in-phase and quadrature-phase signals components are not phase swapped in the other up-conversion unit. Accordingly, the two-way up-conversion can be regarded as the same up-conversion operation used for generating the first and second up-converted signals S_RF 1 and S_RF 2 . Therefore, by employing the circuitry configuration of the up-conversion circuit 320 to merely exchange phases of the in-phase and quadrature-phase signal components during one operation of the same up-conversion, it can be easily achieved for simultaneously processing and transmitting two discontinuous frequency band signals at the same time. Further, the circuitry configuration of phase swapping for the in-phase and quadrature-phase signal components in the operation of up-conversion circuit 320 described above is similar to that for the in-phase and quadrature-phase signal components in the operation of down-conversion circuit 120 as shown in FIG. 1 . Since the operation of phase swapping has been clearly described in foregoing paragraphs, detailed description is omitted here for brevity. In addition, it should be noted that the receiver of FIG. 1 and the transmitter of FIG. 3 can be integrated in a single integrated circuit chip to implement a transceiver circuitry configuration. This modification also falls within the scope of the present invention.

FIG. 4A-FIG . 4 B and FIG. 5A-FIG . 5 B respectively illustrate the operation flow of the receiver as shown in FIG. 1 and the operation flow of the transmitter as shown in FIG. 3 . Provided that substantially the same result is achieved, the steps need not be in the exact order as below and need not be contiguous; that is, other steps can be intermediate. The description of the steps shown in FIGS. 4A-4B and FIG. 5A-5B is detailed in the following:

Step 408 : Generate the in-phase local oscillation differential signal LOI_ 1 and quadrature-phase local oscillation differential signal LOQ_ 1 of the oscillation frequency F C +(N/2)*W;

Step 410 : Perform frequency down-conversion upon the RF signal S_RF to generate the first down-converted signal S_IF 1 according to the in-phase local oscillation differential signal LOI_ 1 and the quadrature-phase local oscillation differential signal LOQ_ 1 ;

Step 412 : Perform frequency down-conversion upon the RF signal S_RF to generate the second down-converted signal S_IF 2 according to the in-phase local oscillation differential signal LOI_ 1 and the quadrature-phase local oscillation differential signal LOQ_ 1 that have been phase swapped;

Step 414 : Generate the in-phase local oscillation differential signal LOI_ 2 and quadrature-phase local oscillation differential signal LOQ_ 2 of the oscillation frequency (N/2)*W;

Step 416 : Perform frequency down-conversion upon the first down-converted signal S_IF 1 to generate the baseband signal S_B 1 according to the in-phase local oscillation differential signal LOI_ 2 and quadrature-phase local oscillation differential signal LOQ_ 2 ;

Step 418 : Perform frequency down-conversion upon the second down-converted signal S_IF 2 to generate the baseband signal S_B 2 according to the in-phase local oscillation differential signal LOI_ 2 and quadrature-phase local oscillation differential signal LOQ_ 2 ;

Step 508 : Generate the in-phase local oscillation signal LOI_ 2 and quadrature-phase local oscillation signal LOQ_ 2 of the oscillation frequency (N/2)*W;

Step 510 : Up-convert the baseband signal S_B 1 into the IF signal S_IF 3 according to the in-phase local oscillation signal LOI_ 2 and quadrature-phase local oscillation signal LOQ_ 2 ;

Step 512 : Up-convert the baseband signal S_B 2 into the IF signal S_IF 4 according to the in-phase local oscillation signal LOI_ 2 and quadrature-phase local oscillation signal LOQ_ 2 ;

Step 514 : Generate the in-phase local oscillation differential signal LOI_ 1 and quadrature-phase local oscillation differential signal LOQ_ 1 of the oscillation frequency F C +(N/2)*W;

Step 516 : Up-convert the IF signal SIF_ 3 to the RF domain to generate the first up-converted signal S_RF 1 according to the in-phase local oscillation differential signal LOI_ 1 and quadrature-phase local oscillation differential signal LOQ_ 1 ;

Step 518 : Up-convert the IF signal SIF_ 4 to the RF domain to generate the second up-converted signal S_RF 2 according to the in-phase local oscillation differential signal LOI_ 1 and quadrature-phase local oscillation differential signal LOQ_ 1 that have been phase swapped, wherein the first and second up-converted signals S_RF 1 and S_RF 2 are used to form the output signal S_RF;

Step 520 : Perform signal driving operation to determine emitting power of the RF signal S_RF;

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.