KR100837243B1 - Predistortion linearization equipment of frequency multiplier and dual mode transmitter using the predistortion linearization equipment - Google Patents

Abstract

The present invention relates to a predistortion linearization device of a frequency multiplier and a dual mode transmitter using the same.

The proposed dual mode transmitter transmits a signal of a dual frequency band using only one transmitter module without separately providing a transmitter module operating in each frequency band to transmit a signal of a dual frequency band. To this end, the dual mode transmitter operates as a power amplifier for amplifying and outputting a signal in a first frequency band of a dual band according to an operation of a driving frequency selection switch, and a frequency multiplier for multiplying and outputting a signal in a second frequency band. do. Here, the frequency multiplier consisting of nonlinear elements compensates for the nonlinear distortion characteristics generated by using the predistortion linearization device.

Therefore, it is possible to transmit a signal of a dual frequency band by using one transmitter module, thereby reducing the unit cost and miniaturizing the transmitter module. In addition, by including the pre-distortion linearization device has an effect of compensating for the nonlinearity of the dual mode transmitter.

Dual-mode transmitter, frequency multiplier, power amplifier, pre-distortion, linearization

Description

Predistortion linearization equipment of frequency multiplier and dual mode transmitter using the predistortion linearization equipment

1 is a block diagram of a dual mode transmitter according to a first embodiment of the present invention.

2 is a block diagram of a dual mode transmitter including a predistortion linearization unit according to a second embodiment of the present invention.

3 is a block diagram of a predistortion linearization unit according to a second embodiment of the present invention.

4A is a flowchart illustrating a predistortion linearization unit according to an operation of a power amplifier in a first mode according to a second embodiment of the present disclosure.

4B is a flowchart of a predistortion linearization unit according to a frequency multiplier operation of a second mode according to a second embodiment of the present invention.

5 is a block diagram of a dual mode transmitter including a predistortion linearizer including a frequency downconversion mixer and a predistorter updater according to a third embodiment of the present invention.

6 is a block diagram of a predistortion linearization unit including a predistorter updater block diagram according to a frequency multiplier operation and a dual mode transmitter according to a third embodiment of the present invention.

FIG. 7 is a diagram illustrating an improved nonlinear output spectrum and linearity of a power amplifier in a dual mode transmitter according to a third embodiment of the present invention.

FIG. 8 illustrates an improved nonlinear output spectrum and linearity of a frequency multiplier in a dual mode transmitter according to a third embodiment of the present invention.

The present invention relates to a dual mode transmitter, and more particularly, to a pre-distortion linearization device of a frequency multiplier and a dual mode transmitter using the same.

Recently, with the development of wireless communication technology, the development of communication systems and components to support this is proceeding very quickly. In particular, many apparatuses for integrating transmission modules of a wireless communication system having separate frequency bands by different transmission standards have been developed.

The conventional dual band transmitter for transmitting two frequency bands has a structure in which a transmitter for transmitting signals of two bands is separately separated. For example, when it is necessary to simultaneously service the 2.4 GHz and 5.8 GHz bands, the dual band transmitter should separately configure a transmitter for transmitting signals in the 2.4 GHz band and a transmitter part for transmitting signals in the 5.8 GHz band. In other words, the existing dual band transmitter is a transmitter portion consisting of a filter, a power gain controller, a voltage controlled oscillator, a frequency mixer, and an amplifier operating on a signal in the 2.4 GHz band, and a filter and power operating on a signal in the 5.8 GHz band. The transmitter section consists of a gain controller, a voltage controlled oscillator, a frequency mixer and an amplifier.

Under this structure, the signal to be modulated in the baseband and input is a transmission path determined by a switch that selects one of the two transmitters. Once a transmission path has been determined, the modulated signal is passed through a power gain controller that can control the magnitude of the signal past the filter in the selected path and then pass through a voltage controlled oscillator, frequency mixer, and amplifier for each frequency band. Finally, it is delivered to the output stage. That is, when the transmitter of the 2.4 GHz band is selected, the final signal is output to the first output along the first path, and when the transmitter of the 5.8 GHz band is selected, the final signal is output to the second output along the second path.

Such a conventional dual band transmitter configuration provides an optimal performance for each mode, but requires a different transmitter component for the dual band, which is expensive and expensive and increases the size of the entire apparatus and has a problem of being complicated.

It is an object of the present invention to provide a dual mode transmitter using one transmitter module to transmit a signal of a dual frequency band.

The present invention also provides a predistortion linearization device that improves the distortion characteristics caused by the nonlinear elements used to construct the transmitter module.

The present invention also provides a dual mode transmitter with improved distortion characteristics using a predistortion linearization device.

A dual mode transmitter for converting the baseband input signal according to a feature of the present invention for achieving the above object into a signal corresponding to one frequency band of the first frequency band and the second frequency band,
In a first mode corresponding to the first frequency band, a power amplifier for amplifying and outputting an input signal is operated. In a second mode corresponding to the second frequency band, a power multiplier is used to multiply and output an input signal. An operating dual band frequency generator; A driving frequency selection switch for selecting a transmission mode of the dual mode transmitter in one of the first mode and the second mode; A pre-distortion linearizer for outputting the baseband input signal by distorting the nonlinear characteristic of the power amplifier in the first mode and distorting the baseband input signal in the inverse of the nonlinear characteristic of the frequency multiplier; An input signal converter configured to remove noise and control power gain of the signal output from the predistortion linearizer; And a frequency up-conversion mixing unit converting the output signal of the input signal converter into a signal of a frequency band corresponding to a mode selected by the driving frequency selection switch and outputting the signal to the dual band frequency generator.

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In addition, the pre-distortion linearization device of the frequency multiplier that is a nonlinear element according to a feature of the present invention,

An amplitude-amplitude predistorter for outputting an amplitude predistortion parameter corresponding to the amplitude of the input signal of the frequency multiplier; An amplitude-phase predistorter for outputting a first phase predistortion parameter corresponding to the amplitude of the input signal of the frequency multiplier; A phase-phase predistorter for outputting a second phase predistortion parameter corresponding to the phase of the input signal of the frequency multiplier; And a predistortion converter configured to distort and output the input signal of the frequency multiplier based on at least one of the amplitude predistortion parameter, the first phase predistortion parameter, and the second phase predistortion parameter.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Hereinafter, a dual mode transmitter according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a dual mode transmitter according to a first embodiment of the present invention, which shows a dual mode transmitter using one transmitter module to transmit a signal of a dual frequency band.

As shown in FIG. 1, the dual mode transmitter according to the first embodiment of the present invention includes an input signal converter 10, a frequency up-conversion mixer 20, a driving frequency selection switch 30, and a dual band frequency. The generation unit 40 is included.

The input signal converter 10 includes a filter 110 and a power gain controller 120. The filter 110 removes and outputs an unwanted signal such as noise from an input signal modulated in a baseband and outputs power. The gain controller 120 controls and outputs power gain of the modulated signal output from the filter 110.

The frequency upconversion mixer 20 includes a voltage controlled oscillator 210 and a frequency mixer 220.

The voltage controlled oscillator 210 is a narrow band voltage controlled oscillator, which generates a local oscillator frequency signal over a band corresponding to 2.9 GHz, which is 1/2 of the 2.4 GHz band and 5.8 GHz, and the frequency mixer 220 generates an input signal. The frequency signal output from the converter 10 is mixed with the frequency output from the voltage controlled oscillator and converted into a signal of the 2.4 GHz or 2.9 GHz band and output. On the other hand, the driving frequency selection switch 30 is a switch for selecting which frequency band of the dual-frequency transmitter to operate. That is, when the user selects one of the transmission modes of the first mode, which is the low band frequency transmission mode of 2.4 GHz, and the second mode, which is the high band frequency transmission mode of 5.8 GHz, the selection signal is driven. It is output from the frequency selection switch 30 to the frequency up-conversion mixing unit 20 and the dual band frequency generator 40.

Accordingly, the voltage controlled oscillator 210 of the frequency upconversion mixing unit 20 generates a frequency signal of 2.4 GHz at the output of the frequency mixer 220 in response to the selection signal output from the driving frequency selection switch 30. It generates a frequency signal in the 2.9 GHz band.

In addition, the dual band frequency generator 40 includes a circuit operating as the power amplifier 410 or the frequency multiplier 420, and the selection signal and the frequency upconversion mixing unit 20 output from the driving frequency selection switch 30. In accordance with the frequency of the signal output from the frequency mixer 220 of the) to operate a 2.4GHz frequency band power amplifier or a frequency multiplier for converting 2.9GHz to 5.8GHz to generate an output signal.

That is, when the user selects the first mode, which is the low band transmission mode, by the driving frequency selection switch 30, the dual band frequency generator 40 operates as the power amplifier 410 and outputs the frequency mixer 220. Amplify and output the signal. On the other hand, when the second mode, which is a high band transmission mode, is selected, the frequency multiplier 420 operates to multiply and output the signal output from the frequency mixer 220.

Hereinafter, the operation of the dual mode transmitter according to the first embodiment of the present invention will be described in detail.

First, it will be described that the dual mode transmitter according to the first embodiment of the present invention operates as an amplifier function in the 2.4 GHz band.

In order to use the transmission function in the low band of the 2.4 GHz band, the driving frequency selection switch 30 is set to the first mode, which is the low band transmission mode, to the frequency up-conversion mixing unit 20 and the dual band frequency generating unit 40. The bias voltage is supplied.

The baseband signal is input to the input signal converter 10 to remove noise and the like through the filter 110, and the power gain is controlled by the power gain controller 120 and then input to the frequency up-conversion mixing unit 20. . At this time, the voltage controlled oscillator 210 in the frequency upconversion mixing section 20 is already driven by the frequency mixer 220 in the frequency upconversion mixing section 20 by the driving frequency selection switch 30. Since the function is set to output, the frequency mixer 220 converts the signal output from the power gain controller 120 with the signal of the frequency band generated by the voltage controlled oscillator 210 and converts it into a signal of the 2.4 GHz band. Output

Next, when the 2.4 GHz band signal output from the frequency mixer 220 is applied to the dual band frequency generator 40, the dual band frequency generator operates as the power amplifier 410 in this frequency band, and the driving frequency selection switch ( 30, the power amplifier 410 amplifies and outputs this signal to maximize output gain and efficiency.

As described above, the dual mode transmitter according to the first embodiment of the present invention may transmit a signal of the 2.4 GHz band by using a power amplifier.

Next, a dual mode transmitter according to a first embodiment of the present invention will be described for operating in the frequency multiplication function in the 5.8GHz band.

In order to use the transmission function in the high band of the 5.8 GHz band, the driving frequency selection switch 30 is set to the second mode, which is the high band transmission mode, to the frequency up-conversion mixing unit 20 and the dual band frequency generating unit 40. The bias voltage is supplied.

The baseband signal is input to the input signal converter 10 to remove noise and the like through the filter 110, and the power gain is controlled by the power gain controller 120 and then input to the frequency up-conversion mixing unit 20. . At this time, the voltage controlled oscillator 210 in the frequency upconversion mixer 20 is already driven by the drive frequency selector switch 30 so that the frequency mixer 220 in the frequency upconversion mixer 20 is 1 in the 5.8 GHz band. Since the function is set to output a signal of 2.9 GHz band which is / 2, the frequency mixer 220 mixes the signal output from the power gain controller 120 with the signal of the frequency band generated by the voltage controlled oscillator 210. To convert the signal into 2.9GHz band and output it.

Next, when the signal of the 2.9GHz band output from the frequency mixer 220 is applied to the dual band frequency generator 40, the dual band frequency generator 40 operates as the frequency multiplier 420 in this frequency band, and is driven. By the frequency selection switch 30, the frequency multiplier 420 multiplies this signal to maximize the output and efficiency, and converts the signal into a 5.8 GHz signal for output.

As such, the dual mode transmitter according to an exemplary embodiment of the present invention may transmit a signal in the 5.8 GHz band using the frequency multiplier function.

The dual mode transmitter according to the first embodiment of the present invention, operating as described above, may transmit a dual band frequency signal according to a bias voltage change and an input signal frequency using one transmitter module.

Next, a dual mode transmitter according to a second embodiment of the present invention will be described.

2 is a block diagram illustrating a dual mode transmitter according to a second embodiment of the present invention.

The structure of the dual mode transmitter according to the second embodiment of the present invention is similar to that of the first embodiment. On the other hand, unlike the first embodiment, it further includes a pre-distortion linearizer 50 for compensating for the distortion characteristics of the power amplifier 410 and the frequency multiplier 420, which are nonlinear elements in the dual band frequency generator 40. There is a characteristic.

Since the structure of the dual mode transmitter according to the second embodiment is similar to that of the dual mode transmitter of the first embodiment described above, only different parts will be described herein.

In the dual mode transmitter including the pre-distortion linearization unit 50 according to the second embodiment of the present invention, as shown in FIG. 2, the input signal converter 10 and the frequency up-conversion mixing according to the first embodiment are illustrated. A unit 20, a drive frequency selection switch 30, a dual band frequency generator 40, and the like, and further includes a pre-distortion linearizer 50.

The added predistortion linearizer 50 generates a new baseband signal I _OUT , Q _OUT predistorted the baseband input signals I _IN , Q _IN , which are input signal converters 10. And a frequency band is converted and output through the frequency upconversion mixing unit 20 to the dual band frequency generating unit 40.

Next, the configuration of the pre-distortion linearization unit 50 will be described with reference to FIG. 3.

3 is a structural diagram of a predistortion linearization unit according to a second embodiment of the present invention.

As shown in FIG. 3, the predistortion linearizer 50 according to the second embodiment of the present invention includes an amplitude estimator 510, an amplitude-amplitude predistorter 520, and an amplitude-phase predistorter 530. ), A pre-distortion converter 540, a phase detector 550, and a phase-phase predistorter 560.

4A and 4B are flowcharts illustrating an operation of the pre-distortion linearization unit 50 according to a mode selection of a dual mode transmitter. FIG. 4A is a flowchart when operating in a first mode, and FIG. 4B is a second mode. It is a flowchart when it operates.

Next, the operation of the pre-distortion linearization unit 50 will be described with reference to FIGS. 4A and 4B.

First, the operation of the pre-distortion linearization unit 50 when the dual mode transmitter operates in the first mode, which is the low band transmission mode, will be described with reference to FIG. 4A.

In the first mode, the predistortion linearization unit 50 performs a predistortion linearization operation to improve the nonlinear distortion characteristics of the power amplifier 410 mode of the dual band frequency generator 40.

In detail, the complex signals I _IN and Q _IN , which are baseband input signals, are input to the amplitude estimator 510 of the pre-distortion linearization unit 50, and the amplitude estimator 510 receives these signals I _IN and Q. The amplitude information r of _IN ) is detected and output to the amplitude-amplitude predistorter 520 and the amplitude-phase predistorter 530. Since the design method for such an amplitude estimator 510 is already well known, a detailed description thereof will be readily understood by those skilled in the art, even if the detailed description thereof is omitted.

According to an embodiment of the present invention, the pre-distortion linearization device, that is, the pre-distortion linearization unit 50 may measure the amplitude and phase distortion of the output signal of the power amplifier 410 in order to perform the pre-distortion linearization in the first mode. The predictable property is used based on the non-linear property of 410. As the nonlinear distortion degree of the power amplifier 410 is predicted as described above, the amplitude and phase predistortion parameters ΔI1 and ΔQ1 corresponding to the amplitude of the signal input to the power amplifier 410 are inverse of the nonlinear distortion characteristics of the power amplifier. It can be calculated by calculating At this time, the amplitude and phase predistortion parameters ΔI1 and ΔQ1 are calculated in the form of complex values.

The predistorters 520 and 530 include a reference table composed of the predistortion parameters ΔI1 and ΔQ1 calculated as described above, and the reference table is stored in a memory so that the amplitude information r of the input signals I _IN and Q _IN ), The pre-distortion parameters ΔI1 and ΔQ1 are output.

That is, the amplitude-amplitude predistorter 520 outputs the amplitude predistortion parameter corresponding to the received amplitude information r to the predistortion converter 540, and the amplitude-phase predistorter 530 receives the input. The phase predistortion parameter corresponding to the amplitude information r is output to the predistortion converter 540.

The predistortion converting unit 540 outputs the baseband input signals I _IN and Q _IN to the amplitude and phase predistortion parameters ΔI1 output from the amplitude-amplitude predistorter 520 and the amplitude-phase predistorter 530. , Based on DELTA Q1, the pre-distorted signals I _OUT and Q _OUT are output.

4B is a flowchart illustrating the operation of the pre-distortion linearization unit 50 when the dual mode transmitter operates in the second mode in the high band transmission mode. In this case, the pre-distortion linearizer 50 performs the pre-distortion linearization operation of the frequency multiplier 420 mode of the dual band frequency generator 40.

Since the operation of the pre-distortion linearization unit 50 when the dual mode transmitter operates in the second mode has many similarities to the operation of the pre-distortion linearization unit 50 when operating in the first mode described above, Detailed description thereof will be omitted.

When the complex signals I _IN and Q _IN , which are baseband input signals, are input to the amplitude estimator 510 and the phase detector 550 of the pre-distortion linearization unit 50, the amplitude estimator 510 receives the input signals I _IN,. The amplitude information r of Q _IN is detected and output, and the phase detector 550 detects and outputs the phase information θ of the input signal (I _IN , Q _IN ). Since the design method is already well known, the detailed description thereof will be easily understood by those skilled in the art, even if the detailed description is omitted.

In the predistortion linearization device, that is, the predistortion linearization unit 50 according to an embodiment of the present invention, in order to perform predistortion linearization in the second mode, the amplitude and phase distortion degree of the output signal of the frequency multiplier 420 may be a frequency multiplier ( Based on the nonlinear characteristic of 420, a predictable characteristic is used. As the degree of nonlinear distortion of the frequency multiplier 420 is predicted as described above, the amplitude and phase predistortion parameters ΔI2 and ΔQ2 corresponding to the amplitude of the signal input to the frequency multiplier 420 are nonlinear distortion of the frequency multiplier 420. It can be calculated by calculating the inverse of the characteristic. At this time, the amplitude and phase predistortion parameters? I2 and? Q2 are calculated in the form of complex values.

The predistorters 520 and 530 include a reference table composed of the predistortion parameters ΔI2 and ΔQ2 calculated as described above, and the reference table is stored in a memory so that the amplitude information r of the input signals I _IN and Q _IN ), The pre-distortion parameters ΔI2 and ΔQ2 are output.

That is, the amplitude-amplitude predistorter 520 outputs the amplitude predistortion parameter corresponding to the received amplitude information r to the predistortion converter 540, and the amplitude-phase predistorter 530 receives the input. The phase predistortion parameter corresponding to the amplitude information r is output to the predistortion converter 540.

In addition, the phase-phase predistorter 560 includes a phase division function for compensating phase multiplication due to frequency multiplication generated by the frequency multiplier, and receives phase information θ from the phase detector 550. The phase predistorter 560 outputs a phase distortion value from the phase information θ through a phase divider and outputs a phase predistortion parameter ΔQ3 corresponding to the distortion phase value to the predistortion converter 540. . The predistortion converter 540 receives the amplitude and phase predistortion parameters ΔI2, ΔQ2, and ΔQ3 from each predistorter and converts the complex signals I _IN and Q _IN , which are baseband input signals, to the predistortion parameters ( The predistorted signals I _OUT and Q _OUT are output by distorting based on DELTA I2, DELTA Q2, and DELTA Q3.

The dual mode transmitter including the pre-distortion linearization unit 50 according to the second embodiment of the present invention, which operates as described above, is a power that is an operation mode of the dual band frequency generator 40 of the dual mode transmitter. There is an effect of improving the nonlinear distortion characteristics of the amplifier 410 mode and the frequency multiplier 420 mode.

That is, in the first mode, the pre-distortion linearization unit 50, in the first mode, amplitude-amplitude distortion (AM-AM) and amplitude-phase distortion of the power amplifier generated in proportion to the magnitude of the input complex signal. (AM-PM: Amplitute to Phase Modulation) has the effect of improving the characteristics. Further, in the second mode, not only the amplitude-amplitude distortion and the amplitude-phase distortion characteristics of the frequency multiplier generated in proportion to the magnitude of the input complex signal are compensated, but also the frequency multiplier generated in response to the phase of the input signal. It has the effect of compensating for phase-phase distortion (PM-PM) characteristics.

In addition, the pre-distortion linearization unit 50 according to the second embodiment of the present invention may be implemented using a digital signal processor (DSP) without implementing an RF analog device. Thus, it is possible to implement a low-cost dual-mode transmitter that is more reliable than using expensive RF analog devices and has low noise and low power operation requirements.

Next, a dual mode transmitter according to a third embodiment of the present invention will be described.

5 is a structural diagram of a dual mode transmitter according to a third embodiment of the present invention. The dual mode transmitter according to the third embodiment of the present invention has a structure further including a predistorter updater 570.

The structure of the dual mode transmitter according to the third embodiment of the present invention is similar to that of the second embodiment, except that the structure of the predistortion linearization unit 50 is different from the second embodiment. Detailed description of the same structures and functions as those of the second embodiment will be omitted, and only different portions will be described.

The dual mode transmitter according to the third embodiment of the present invention, the input signal converter 10, the frequency up-conversion mixing unit 20, the driving frequency selection switch 30, the dual band frequency generator according to the second embodiment 40, a pre-distortion linearizer 50 to which a frequency down-conversion mixer 60 and a predistorter updater 570 are added.

The predistortion linearizer 50 according to the third embodiment of the present invention includes an amplitude estimator 510, an amplitude-amplitude predistorter 520, an amplitude-phase predistorter 530, and a predistortion converter 540. , Phase detector 550, phase-phase predistorter 560, and in particular a predistorter updater 570.

The frequency downconversion mixing unit 60 according to the third embodiment of the present invention down-converts the output of the dual band frequency generator 40 to obtain a baseband signal and outputs the signal to the predistorter updating unit 570. do.

Since the operation of the pre-distortion linearization unit 50 when the dual mode transmitter operates in the first mode can be explained from the following second mode operation among the second and third embodiments of the present invention, description thereof is omitted here. do.

Hereinafter, the structure and operation of the pre-distortion linearization unit 50 according to the third embodiment of the present invention will be described with reference to FIG. 6.

FIG. 6 is a flowchart illustrating an operation state of the pre-distortion linearization unit 50 when the dual mode transmitter operates in the second mode.

The amplitude estimator 510, the phase detector 550, the amplitude-amplitude predistorter 520, and the amplitude-phase predistorter 530 have the same structure as the second embodiment described above, and the predistortion converter In operation 540, the signals output from the input signal converter are predistorted and output to the frequency up-conversion mixing unit 20 based on the amplitude and phase predistortion parameters provided from each predistorter as in the second embodiment.

The predistorter updating unit 570 may include the frequency down-conversion mixing unit 60, the output signal amplitude estimator 5710, the output signal phase detector 5720, the signal comparator 5730, and the update unit as shown in FIG. 6. The parameter generator 5940 is included.

When operating in the second mode, the predistorter updating unit 570 and the amplitude (r _OUT ) and phase (θ _OUT ) information detected from the signal fed back from the frequency multiplier 420 and the frequency down-conversion mixing unit 60. A difference value is calculated by comparing the amplitude r _IN and phase θ _IN information of the baseband input signals I _IN and Q _IN . Then, according to this value, the pre-distortion parameters stored in the reference tables in the amplitude-amplitude predistorter 520 and the amplitude-phase predistorter 530 are updated.

When the dual mode transmitter operates in the second mode, the frequency down-conversion mixing unit 60 receives a signal fed back from the frequency multiplier 420 output of the dual band frequency generating unit 40 and frequency-converts to baseband. Output

The signal output from the frequency downconversion mixing unit 60 is input to an output signal amplitude estimator 5710 and an output signal phase detector 5720. The output signal amplitude estimator 5710 detects and outputs the amplitude information r _OUT of the signal output from the frequency downconversion mixing section 60, and the output signal phase detector 5720 outputs from the frequency downconversion mixing section 60. Phase information (θ _OUT ) of the received signal is detected and output.

The signal comparator 5730 is provided with amplitude r _IN and phase θ _IN information received from the amplitude estimator 510 and the phase detector 550, and from the output signal amplitude estimator 5710 and the output signal phase detector 5720. The received amplitude r _OUT and phase θ _OUT are compared with each other, and the difference values Δr and Δθ are output to the update parameter generator 5740.

Accordingly, the update parameter generator 5740 calculates complex amplitude and phase predistortion parameters ΔI and ΔQ from the received amplitude and phase difference values Δr and Δθ, and calculates the calculated amplitude and phase predistortion parameters. The reference tables of the amplitude-amplitude predistorter 520 and the amplitude-phase predistorter 530 stored in the memory are updated based on (ΔI, ΔQ). Accordingly, the updated reference table of each predistorter is applied to the next input signal.

According to the third embodiment of the present invention, the out-of-band distortion of the fourth-order intermodulation distortion (IMD) term caused by phase division in the second mode is compensated by the predistorter updating unit 570. Thus, the output spectrum of the dual mode transmitter has the effect of satisfying the International Electro-Electronic Society (IEEE) standard transmission spectrum mask specification.

7 and 8 illustrate an output spectrum of a dual mode transmitter according to an embodiment of the present invention. In detail, the power amplifier output spectrum in the first frequency band mode and the frequency multiplier output spectrum in the second frequency band mode according to the modulation signal input modulated in the baseband are respectively shown. Here, it was used in the 2.4GHz, 5.8GHz WLAN frequency band.

According to the accompanying FIG. 7, it can be seen that the output spectrum of the power amplifier in the dual mode transmitter according to the embodiment of the present invention improves an adjacent channel power ratio (ACPR) by about 10 dB at the same output power. In addition, according to FIG. 8, it can be seen that the output spectrum of the frequency multiplier can obtain an output of which the distortion characteristic is greatly improved as compared with before the linearization which represents the nonlinear output spectral characteristic.

As a result, ACPR characteristics of 26 dB, 10 dB, and 9 dB, respectively, have been improved compared to before linearization at frequencies 11 MHz, 20 MHz, and 30 MHz away from the center frequency, respectively, and the transmission spectrum of the International Electrotechnical Society (IEEE) standard is improved. The mask specification is satisfied.

Although the present invention has been described with reference to the most practical and preferred embodiments, it is not intended to limit the invention but various modifications are possible.

For example, when the dual mode transmitter of the present invention operates in the first mode, the predistortion parameter calculated in advance in correspondence with the nonlinear distortion characteristic of the power amplifier in the form of a reference table for predistortion linearization of the power amplifier is stored in the memory. Although the pre-distortion linearization unit has been configured and presented, the non-linear distortion characteristic of the power amplifier is improved by using the frequency down-conversion mixing unit 60 and the pre-distorter updating unit 570 with reference to the third embodiment of the present invention. The present invention may be applied to a case in which changes are made, and a person skilled in the art may easily implement the present invention in various modified forms.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

According to an embodiment of the present invention, a dual mode transmitter for transmitting signals of two frequency bands to one transmitter module has an effect of miniaturizing price and size in the dual band transmitter market.

In addition, the pre-distortion linearization device according to the present invention has the effect of improving the signal distortion of the dual-mode transmitter by compensating the non-linear distortion characteristics of the dual mode transmitter including the non-linear elements such as power amplifier and frequency multiplier with the pre-distortion linearization device. .

Claims (12)

A dual mode transmitter for converting a baseband input signal into a signal corresponding to one of the first frequency band and the second frequency band, and transmitting the signal; In a first mode corresponding to the first frequency band, a power amplifier for amplifying and outputting an input signal is operated. In a second mode corresponding to the second frequency band, a power multiplier is used to multiply and output an input signal. An operating dual band frequency generator; A driving frequency selection switch for selecting a transmission mode of the dual mode transmitter in one of the first mode and the second mode; A pre-distortion linearizer for outputting the baseband input signal by distorting the nonlinear characteristic of the power amplifier in the first mode and distorting the baseband input signal in the inverse of the nonlinear characteristic of the frequency multiplier; An input signal converter configured to remove noise and control power gain of the signal output from the predistortion linearizer; And A frequency up-conversion mixing unit for converting an output signal of the input signal converter into a signal of a frequency band corresponding to a mode selected by the driving frequency selection switch and outputting the signal to the dual band frequency generator; Dual mode transmitter comprising a. The method of claim 1, The pre-distortion linearization unit, An amplitude-amplitude predistorter for outputting an amplitude predistortion parameter corresponding to the amplitude of the baseband input signal; An amplitude-phase predistorter for outputting with a first phase predistortion parameter corresponding to the amplitude of the baseband input signal; A phase-phase predistorter for outputting a second phase predistortion parameter corresponding to the phase of the baseband input signal; And A pre-distortion converter for distorting the baseband input signal based on at least one of the amplitude pre-distortion parameter, the first phase pre-distortion parameter, and the second phase pre-distortion parameter Dual mode transmitter comprising a. The method of claim 2, The pre-distortion converter, To distort the baseband input signal, The amplitude predistortion parameter and the first phase predistortion parameter when in the first mode, And in the second mode, use the amplitude predistortion parameter, the first phase predistortion parameter and the second phase predistortion parameter. The method of claim 2, The phase-phase predistorter includes a phase divider, which calculates a phase distortion value from the phase of the baseband input signal through the phase divider, and outputs the second phase predistortion parameter in response to the phase distortion value. Dual mode transmitter, characterized in that. The method of claim 2, The amplitude-amplitude predistorter, A first reference table in which a first amplitude distortion value corresponding to the nonlinear distortion characteristic of the power amplifier and a second amplitude distortion value corresponding to the nonlinear distortion characteristic of the frequency multiplier are stored as the amplitude predistortion parameter, The amplitude-phase predistorter, A second reference table including a first phase distortion value corresponding to the nonlinear distortion characteristic of the power amplifier and a second phase distortion value corresponding to the nonlinear distortion characteristic of the frequency multiplier as the first phase predistortion parameter. Mode transmitter. The method of claim 5, In the case of operating in the second mode further includes a frequency down-conversion mixing unit for outputting the frequency down-converted output signal of the frequency multiplier, The pre-distortion linearization unit, Obtaining an amplitude difference and a phase difference between the output signal of the frequency downconversion mixing unit and the baseband input signal, updating the first reference table in response to the amplitude difference, and updating the second reference table in response to the phase difference The dual mode transmitter, characterized in that it further comprises a distortion updater. The method of claim 2, And implementing the predistortion linearizer by a digital signal processor. In the pre-distortion linearization device of the frequency multiplier that is a nonlinear element, An amplitude-amplitude predistorter for outputting an amplitude predistortion parameter corresponding to the amplitude of the input signal of the frequency multiplier; An amplitude-phase predistorter for outputting a first phase predistortion parameter corresponding to the amplitude of the input signal of the frequency multiplier; A phase-phase predistorter for outputting a second phase predistortion parameter corresponding to the phase of the input signal of the frequency multiplier; And A predistortion converter for distorting and outputting the input signal of the frequency multiplier based on at least one of the amplitude predistortion parameter, the first phase predistortion parameter, and the second phase predistortion parameter. Pre-distortion linearization device of the frequency multiplier comprising a. The method of claim 8, The phase-phase predistorter includes a phase divider, which calculates a phase distortion value from a phase of an input signal of the frequency multiplier through the phase divider, and outputs a second phase predistortion parameter corresponding to the phase distortion value. Pre-distortion linearization device of the frequency multiplier, characterized in that. The method of claim 8, The amplitude-amplitude predistorter, An amplitude reference value corresponding to the nonlinear distortion characteristic of the frequency multiplier includes a first reference table used as an amplitude predistortion parameter, The amplitude-phase predistorter, And a second reference table in which a phase distortion value corresponding to the nonlinear distortion characteristic of the frequency multiplier is used as a phase predistortion parameter. The method of claim 8, The predistortion linearization device, A signal comparator for calculating an amplitude difference and a phase difference between a frequency down-converted signal obtained by converting an output signal of the frequency multiplier to a frequency band of a baseband input signal and an input signal of the predistortion linearization device; And An update parameter generator for updating the first reference table in response to the amplitude difference and updating the second reference table in response to the phase difference Pre-distorter updater including Pre-distortion linearization of the frequency multiplier, characterized in that it further comprises Device. The method of claim 8, The predistortion linearization device of the frequency multiplier, characterized in that implemented by a digital signal processor.

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