WO2008072700A1

WO2008072700A1 - Transmission device

Info

Publication number: WO2008072700A1
Application number: PCT/JP2007/074043
Authority: WO
Inventors: Tsutomu Hibino; Hitomaro Tougou; Shinji Ookawa; Shiro Masumoto
Original assignee: Panasonic Corporation
Priority date: 2006-12-14
Filing date: 2007-12-13
Publication date: 2008-06-19

Abstract

Provided is a transmission device capable of reducing the cost by mitigating the condition posed on the power voltage control unit and increase the power efficiency. In the transmission device (100), a power voltage control unit (106) controls power voltage applied to a power amplifier in accordance with an amplitude component of a modulation signal and an amplitude signal correction unit (105) is arranged at the input stage of the voltage control unit (106) for making a correction to reduce the amplitude width between the maximum amplitude and the minimum amplitude of the amplitude component and removing a high-frequency component from the amplitude component after the correction. This reduces the amplitude width between the maximum amplitude and the minimum amplitude of the amplitude component and narrows the bandwidth by removing the high-frequency component, thereby mitigating the condition concerning the dynamic range and the bandwidth for the power voltage control unit (106). Thus, it is possible to realize reduction of the cost of the transmission device (100) on which the power voltage control unit (106) is mounted and increase the power efficiency.

Description

Specification

Transmitter

Technical field

The present invention relates to a transmission device that amplifies and transmits a modulation signal including an amplitude modulation component and a phase modulation component.

Background art

[0002] With recent development of mobile communication technology, there is an increasing demand for lower power consumption of mobile terminals and base station devices. In order to reduce the power consumption of mobile terminals and base station devices, it is effective to increase the efficiency of the transmission devices that account for the majority of the power consumption. In addition, in order to ensure communication quality and reduce the influence on other communication systems, the transmission apparatus is required to transmit a modulated signal including an amplitude modulation component and a phase modulation component without distortion. As a configuration of a transmission apparatus that satisfies these requirements, a transmission apparatus using an EER (Envelope Elimination and Restoratioru method) has been proposed (for example, see Non-Patent Document 1).

[0003] With reference to FIG. 1 and FIG. 2, the operation of a transmission apparatus using the EER scheme will be described. A transmitter using the EER system includes an input terminal 1, a limiter 2, an amplitude detector 3, a power supply voltage controller 4, and a power amplifier 5. The input terminal 1 receives a modulation signal as shown in FIG. 2A having a phase modulation component and an amplitude modulation component. The modulated signal input from the input terminal 1 is branched into two, one being input to the limiter 2 and the other being input to the amplitude detector 3. The limiter 2 removes the amplitude modulation component of the input modulation signal and outputs a phase modulation signal having a constant envelope as shown in FIG. 2B. The amplitude detector 3 detects the amplitude component of the input modulation signal and outputs an amplitude signal as shown in FIG. 2C. The power supply voltage control unit 4 controls the power supply voltage of the power amplifier 5 according to the amplitude of the output signal of the amplitude detection unit 3. The power amplifier 5 amplifies the phase modulation signal having a constant envelope that is the output signal of the limiter 2. At this time, since the power supply voltage of the power amplifier 5 changes according to the amplitude signal of FIG. 2C, the gain of the power amplifier 5 changes. As a result, the output signal of the power amplifier 5 is an amplified input signal as shown in FIG. 2D.

[0004] In such a transmitter using the EER method, a phase modulation signal having a constant envelope is transmitted. Since amplification is performed by the power amplifier 5, it is possible to avoid distortion due to amplitude fluctuation of the high-frequency signal input to the power amplifier. As a result, distortion due to amplitude fluctuation is large, but power efficiency is high, and class E amplifiers and class F amplifiers can be used as power amplifiers. Is possible.

[0005] Incidentally, it is known that the EER system has an operation limit when the output power of the power amplifier becomes low, that is, on the low output side. As a method for solving this problem, the power amplifier is operated linearly when the amplitude of the input modulation signal is equal to or smaller than a predetermined threshold value, and the power amplifier is operated when the amplitude is equal to or larger than the predetermined threshold value. There is a problem when the EER is operated (for example, Patent Document 1). Various methods have been proposed for switching between linear operation and EER operation of power amplifiers (for example, Patent Documents 2 and 3).

[0006] A method of switching between linear operation and EER operation will be described with reference to FIG. When switching between linear operation and EER operation, change the characteristics of limiter 2 and amplitude detector 3 in Fig. 1 to those shown in Fig. 3. When the limiter 2 and the amplitude detector 3 having the characteristics shown in FIG. 3 are used, when the amplitude of the input signal is smaller than a predetermined threshold, the envelope of the output signal of the limiter 2 changes according to the input signal. In addition, the output signal of the amplitude detector 3 is a constant value. When the amplitude of the input signal is larger than a predetermined threshold value, the output signal of the limiter 2 becomes a phase modulation signal having a constant envelope, and the output signal of the amplitude detector 3 changes according to the amplitude of the input signal. Therefore, when the amplitude of the input signal is smaller than the predetermined threshold, the power amplifier 5 amplifies the input signal by a linear operation with a constant power supply voltage, and when the amplitude of the input signal is larger than the predetermined threshold, The amplifier 5 amplifies the input signal by the EER method. Patent Document 1: Japanese Patent Application Laid-Open No. 2004-104194 (Page 9, Figure 4)

Patent Document 2: JP 2005-184273 A (page 16, Fig. 7)

Patent Document 3: Japanese Patent Laid-Open No. 2005-198109 (page 11, Fig. 5)

Non-Patent Document 1: F. H. Raab, Proc. Sixth Int. Conf. HF Radio Syst ems and Techniques (HR '94), pp. 21— 25, July 4— 7, 1994.

Disclosure of the invention

Problems to be solved by the invention

[0007] By the way, in the transmitter using the conventional EER scheme, the amplitude detector has a nonlinear characteristic. Therefore, the band of the amplitude signal for controlling the power supply voltage is widened. Specifically, the bandwidth of the amplitude signal that is the output signal of the amplitude detection unit is expanded several times that of the input signal.

[0008] When the bandwidth of the amplitude signal is wide as described above, the power supply voltage control unit needs to control the power supply voltage of the power amplifier at a high frequency. This strict! / Power supply voltage control unit that satisfies the requirements is generally expensive and has low power efficiency. When the power efficiency of the power supply voltage control unit is lowered, there is a problem that the power efficiency of the entire transmission device is lowered even if the power efficiency of the main power amplifier is high.

[0009] An object of the present invention is to provide a transmitter capable of realizing a reduction in price and increasing power efficiency by relaxing requirements for a power supply voltage control unit. Means for solving the problem

[0010] A transmission apparatus according to the present invention includes a power amplifier that amplifies an input modulation signal according to an applied power supply voltage, and a power supply voltage control that controls an applied power supply voltage of the power amplifier according to an amplitude component of the modulation signal. And an amplitude component for correcting the amplitude width between the maximum amplitude and the minimum amplitude of the amplitude component to be small and further removing a high frequency component from the corrected amplitude component. And a correction means.

The invention's effect

[0011] According to the present invention, it is possible to provide a transmission device that can realize a reduction in price and increase power efficiency by relaxing the requirements for the power supply voltage control unit. Brief Description of Drawings

FIG. 1 is a block diagram showing a configuration of a conventional transmission device

FIG. 2 is a diagram showing signal waveforms at various parts in a conventional transmitter.

[Fig. 3] Diagram showing characteristics of components in a conventional transmitter

FIG. 4 is a block diagram showing a configuration of a transmission apparatus according to Embodiment 1 of the present invention.

FIG. 5 is a block diagram showing the configuration of the amplitude signal correction unit in FIG.

FIG. 6 is a diagram showing the characteristics of the low-amplitude component limiting unit and the low-pass filter unit of FIG.

FIG. 7 is a block diagram showing the configuration of the modulation signal correction unit in FIG.

FIG. 8 is a block diagram showing the configuration of the correction coefficient calculation unit in FIG.

FIG. 9 is a diagram showing phase characteristics and amplitude characteristics of the modulation signal correction unit in FIG. FIG. 10 is a diagram showing signal waveforms at various parts of the amplitude signal correction unit in FIG.

FIG. 11 is a block diagram showing a configuration of a transmitting apparatus according to Embodiment 2.

FIG. 12 is a block diagram showing the configuration of the correction characteristic updating unit in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that, in the embodiments, the same components are denoted by the same reference numerals, and the description thereof is omitted because it is duplicated.

[0014] (Embodiment 1)

FIG. 4 is a block diagram showing a configuration of transmitting apparatus 100 according to Embodiment 1 of the present invention. Transmitting apparatus 100 to which the EER scheme in this embodiment is applied includes an input unit 101 to which a modulation signal having a phase modulation component and an amplitude modulation component is input, and a transmission unit 102 that outputs a high-frequency signal from the input modulation signal A power amplifier 103 that amplifies the high-frequency signal that is the output of the transmitter 102, an amplitude detector 104 that detects the amplitude component of the modulated signal input to the input unit 101, and a detected amplitude component signal (in the figure, An amplitude signal correction unit 105 that corrects the amplitude signal c) and outputs the corrected signal as a control signal, and a power source that controls the power supply voltage of the power amplifier 103 based on the control signal output from the amplitude signal correction unit 105 A voltage control unit 106 and a force are also configured.

[0015] The amplitude signal correction unit 105 determines the amplitude width between the maximum amplitude and the minimum amplitude of the amplitude component signal detected by the amplitude detection unit 104 (hereinafter referred to as "maximum minimum amplitude width"). Amplitude signal correction processing is performed in which correction is performed to reduce the amplitude and further, high-frequency components are removed from the corrected amplitude component signal. The power supply voltage control unit 106 controls the power supply voltage of the power amplifier 103 based on the amplitude component signal after the amplitude signal correction processing.

As shown in FIG. 5, the amplitude signal correcting unit 105 includes a low amplitude component limiting unit 203 and a low-pass filter unit 204.

The low amplitude component limiting unit 203 corrects the amplitude component signal so as to reduce the maximum and minimum amplitude width of the amplitude component signal detected by the amplitude detection unit 104. The low-amplitude component limiting unit 203 corrects the input signal by amplifying the amplitude of the portion below the predetermined threshold value from the amplitude component signal to the threshold value. The portion of the amplitude component signal that is greater than or equal to a predetermined threshold For the minute, the input signal is corrected by setting the amplitude value according to the amplitude of the portion. That is, as shown in FIG. 6A, the low-amplitude component limiting unit 203 sets an output signal having a certain amplitude value for a portion of the input signal up to a certain amplitude, and exceeds the certain amplitude value. An output signal having an amplitude value corresponding to the amplitude of the part has an output characteristic.

[0018] The low-pass filter unit 204 passes only the low frequency component of the amplitude component signal corrected by the low amplitude component limiting unit 203. In other words, the low-pass filter unit 204 removes a sharp portion (first-order differential discontinuity) generated in the amplitude component signal by the correction in the low amplitude component limiting unit 203. That is, the low-pass filter unit 204 has a filter characteristic as shown in FIG. 6B.

The transmission unit 102 sends an input signal of the power amplifier 103 necessary for obtaining an output signal of the desired power amplifier 103 to the input unit 101 at an applied power supply voltage applied to the power source of the power amplifier 103. Formed from the input modulation signal.

Transmitting section 102 has modulation signal correction section 111 that corrects the amplitude component and phase component of the input modulation signal based on the applied power supply voltage and the desired output signal of power amplifier 103, and the amplitude component and phase component are And a signal level conversion unit 112 for converting the level of the corrected modulation signal.

As shown in FIG. 7, the modulation signal correction unit 111 includes a correction coefficient calculation unit 303, a modulation signal phase correction unit 304, and a modulation signal amplitude correction unit 305.

The correction coefficient calculation unit 303 calculates the amplitude component correction amount and the phase component correction amount based on the applied power supply voltage and the desired output signal of the power amplifier 103.

As shown in FIG. 8, the correction coefficient calculation unit 303 includes an amplitude calculation unit 404, a power supply voltage calculation unit 405, a phase correction coefficient calculation unit 406, and an amplitude correction coefficient calculation unit 407.

The amplitude calculation unit 404 calculates the amplitude value of the input modulation signal, and outputs the obtained amplitude value to the phase correction coefficient calculation unit 406 and the amplitude correction coefficient calculation unit 407. The power supply voltage calculation unit 405 calculates the power supply voltage of the power amplifier 103 corresponding to the modulation signal from the input modulation signal, and outputs the obtained power supply voltage to the phase correction coefficient calculation unit 406 and the amplitude correction coefficient calculation unit 407. The phase correction coefficient calculation unit 406 determines the amplitude value of the input modulation signal and the modulation signal. The phase correction coefficient (phase component correction amount) is calculated based on the power supply voltage corresponding to the signal. As shown in FIG. 9A, the phase correction coefficient calculation unit 406 has a calculation characteristic of a phase correction coefficient with respect to an amplitude value that is different for each power supply voltage. The amplitude correction coefficient calculation unit 407 calculates an amplitude correction coefficient (amplitude component correction amount) based on the amplitude value of the input modulation signal and the power supply voltage corresponding to the modulation signal. As shown in FIG. 9B, the amplitude correction coefficient calculation unit 407 has a calculation characteristic of the amplitude correction coefficient with respect to the amplitude value, which is different for each power supply voltage.

FIG. 9A is a diagram showing the passing phase of the output signal output from the output terminal 302 with respect to the amplitude of the input signal input to the input terminal 301, and FIG. FIG. 4 is a diagram showing the amplitude of an output signal output from an output terminal 302 with respect to the input signal amplitude. The passing phase and amplitude characteristics of the modulation signal correcting unit 111 are not a single curve but a set of a plurality of curves. This is because the output of the power supply voltage calculation unit 405 is not uniquely determined with respect to the output of the amplitude calculation unit 404.

Returning to FIG. 7, modulation signal phase correction section 304 corrects the phase of the input modulation signal in accordance with the phase correction coefficient calculated by correction coefficient calculation section 303. The modulation signal amplitude correction unit 305 corrects the amplitude of the input modulation signal in accordance with the amplitude correction coefficient calculated by the correction coefficient calculation unit 303.

Next, the operation of transmitting apparatus 100 having the above configuration will be described.

An input signal a having a phase modulation component and an amplitude modulation component input from the input unit 101 is branched into two and input to the transmission unit 102 and the amplitude detection unit 104.

[0029] The amplitude signal correction unit 105 performs correction to reduce the maximum / minimum amplitude width of the amplitude component signal (amplitude signal c in the figure) detected by the amplitude detection unit 104, and further performs amplitude correction after the correction. Amplitude signal correction processing is performed to remove high frequency components from the minute signal.

[0030] The input amplitude signal c has a small amplitude portion as shown in FIG. 10A. In addition, there is a non-differentiable amplitude change near zero amplitude. First, the amplitude signal correction unit 105 performs correction to reduce the maximum / minimum amplitude width of the amplitude component signal detected by the amplitude detection unit 104. Specifically, the amplitude of the portion of the amplitude signal c less than the predetermined threshold is amplified to the threshold value. That is, the corrected signal (intermediate signal f) has a shape in which the amplitude is raised to a predetermined threshold as shown in FIG. 10B. This As a result, the dynamic range of the power supply voltage control unit 106 in the output stage can be reduced, and the demand on the power supply voltage control unit 106 regarding the dynamic range can be relaxed.

[0031] However, in the intermediate signal f, a sharp portion (a point that cannot be differentiated, a discontinuous point of the first derivative) generated in the modulation signal due to the correction occurs. That is, the intermediate signal f still contains a high-frequency component. When the intermediate signal f is used in this form in the power supply voltage control unit 106, the power supply voltage control unit 106 has a wide band from low frequency to high frequency. It is necessary to have a configuration that can handle this. In other words, the bandwidth requirement for the power supply voltage control unit 106 remains severe, and as a result, the expensive power supply voltage control unit 106 needs to be mounted on the transmission device 100.

Therefore, the amplitude signal correction unit 105 further performs a process of removing the high frequency component from the corrected amplitude component signal. Specifically, the amplitude signal correction unit 105 passes the low frequency component of the input intermediate signal f without attenuation, and passes the high frequency component of the intermediate signal f attenuated at a predetermined rate. That is, the band-limited signal (control signal d) has a smooth shape as shown in FIG. 10C. By doing so, the sharp portion generated by the correction in the intermediate signal f can be removed, so that the control signal d having a narrow band can be obtained. As a result, the bandwidth of the amplitude signal input to the power supply voltage control unit 106 in the output stage can be narrowed, and the request regarding the bandwidth to the power supply voltage control unit 106 can be relaxed. In this way, by eliminating the points that cannot be differentiated as seen in Figs. 10A and 10B, the high-frequency component is reduced compared to the amplitude signal c, and the dynamic range of the control signal d and the intermediate signal f is equivalent. Since the dynamic range is reduced compared to the amplitude signal c, the demand on the power supply voltage control unit 106 can be relaxed, so that the power supply voltage control unit 106 can be made smaller and less expensive.

[0033] On the other hand, if the power supply voltage changes in accordance with the correction of the amplitude component signal, if no adjustment is made to the input signal of the power amplifier 103, the output signal of the power amplifier 103 becomes the desired power. There is a possibility of deviating from the value and phase. In other words, the distortion caused by the correction of the amplitude signal and the distortion caused by the change of the power supply voltage are the power amplifier 103. May occur in the output signal.

[0034] Therefore, in the transmission device 100, the input signal of the power amplifier 103 necessary for obtaining the output signal of the desired power amplifier 103 at the applied power supply voltage in which the transmission unit 102 is applied to the power supply of the power amplifier 103, Formed from the input modulation signal. Specifically, the modulation signal correction unit 111 calculates the amplitude component correction amount and the phase component correction amount based on the calculated amplitude value of the input modulation signal and the applied power supply voltage of the power amplifier 103, and calculates the calculated amplitude. The phase and amplitude of the input modulation signal are corrected using the component correction amount and the phase component correction amount. In this way, even if the applied power supply voltage changes every moment due to the correction of the amplitude component signal, the output signal is converted to the desired power value and phase based on the applied power supply voltage and the desired output signal of the power amplifier 103. Therefore, the input signal (modulation signal) of the power amplifier 103 can be corrected in a form necessary to achieve the above. In this way, it is possible to realize the transmitting apparatus 100 that can simultaneously compensate for both distortion caused by the correction of the amplitude component signal and distortion caused by a change in the power supply voltage.

Specifically, the modulation signal correction unit 111 receives a modulation signal (input signal a) from the input terminal 301 and outputs a signal whose amplitude and phase are corrected from the output terminal 302. The modulation signal input from the input terminal 301 is branched into two, one input to the correction coefficient calculation unit 303 and the other input to the modulation signal phase correction unit 304.

The correction coefficient calculation unit 303 calculates the amount of phase and amplitude correction from the input signal a that has been input, and outputs it to the modulation signal phase correction unit 304 and the modulation signal amplitude correction unit 305, respectively. More specifically, the input signal a input from the input terminal 401 is branched into two, one being input to the amplitude calculator 404 and the other being input to the power supply voltage calculator 405. The amplitude calculation unit 404 calculates the amplitude value of the input signal a inputted, and outputs the calculation result to the phase correction coefficient calculation unit 406 and the amplitude correction coefficient calculation unit 407. The power supply voltage calculation unit 405 calculates the power supply voltage supplied to the power amplifier 103 from the input signal a input, and outputs the calculation result to the phase correction coefficient calculation unit 406 and the amplitude correction coefficient calculation unit 407. Phase correction coefficient calculation section 406 calculates a phase correction coefficient using the amplitude value of input signal a obtained from amplitude calculation section 404 and the power supply voltage applied to power amplifier 103 obtained from power supply voltage calculation section 405. The calculated phase correction coefficient is output from the phase correction coefficient output terminal 402, and the modulated signal Used in the phase correction unit 304. The amplitude correction coefficient calculation unit 407 calculates the amplitude correction coefficient using the amplitude value of the input signal a obtained from the amplitude calculation unit 404 and the power supply voltage applied to the power amplifier 103 obtained from the power supply voltage calculation unit 405. The calculated amplitude correction coefficient is output from the amplitude correction coefficient output terminal 403 and used in the modulation signal amplitude correction unit 305.

The modulation signal phase correction unit 304 corrects the phase of the input signal a input from the input terminal 301 in accordance with the phase correction amount input from the correction coefficient calculation unit 303. The corrected input signal is input to the modulation signal amplitude correction unit 305. The modulation signal amplitude correction unit 305 corrects the amplitude of the input signal in which the phase input from the modulation signal phase correction unit 304 is corrected according to the amplitude correction amount input from the correction coefficient calculation unit 303. The signal whose phase and amplitude are corrected by the modulation signal phase correction unit 304 and the modulation signal amplitude correction unit 305 is output to the output terminal 302.

In the above description, the amplitude correction is performed after the phase correction! /, And the modulation signal level complementary correction unit 304 and the modulation signal amplitude correction unit 305 are characteristic in the present invention even if the order of the modulation signal amplitude correction unit 305 is reversed. Functions can be realized as well.

In addition, instead of the output signal of the amplitude calculation unit 404, the amplitude signal c that is the output signal of the amplitude detection unit 104 can be used as a signal used for the calculation of the amplitude correction coefficient and the phase correction coefficient. Further, as a signal used for amplitude correction coefficient calculation and phase correction coefficient calculation, a control signal d that is an output signal of the amplitude signal correction unit 105 can be used instead of the output signal of the power supply voltage calculation unit 405.

Next, the reason for using the modulation signal correcting unit 111 having the configuration and characteristics as shown in FIGS. 7 to 9 will be described.

[0041] When attention is paid to the characteristics of the power amplifier 103, the amplitude and phase of the output signal e also change depending on the high-frequency signal b that is the output signal of the transmission unit 102 and only the power supply voltage that is the output signal of the power supply voltage control unit 106. To do. In the transmission device 100 of the present invention, since the amplitude signal correction unit 105 includes the low-pass filter 204, the power supply voltage of the power amplifier 103 is not uniquely determined with respect to the amplitude of the input signal a. Similarly, since the amplitude signal correction unit 105 includes the low amplitude component limiting unit 203, the input signal is supplied to the power supply voltage of the power amplifier 103. The amplitude of issue a is not uniquely determined. Therefore, in order to minimize the distortion generated in the power amplifier 103, it is necessary to correct the phase and amplitude of the input signal a according to the power supply voltage applied to the power amplifier 103 and the amplitude of the input signal a. .

By using the correction coefficient calculation unit 303 having the configuration as shown in FIG. 8, an appropriate phase correction amount and amplitude correction according to the power supply voltage supplied to the power amplifier 103 and the amplitude of the input signal a. A positive amount can be calculated. In addition, by using the modulation signal correction unit 111 having the configuration as shown in FIG. 7, appropriate phase correction and amplitude correction can be performed on the input signal a. At this time, in order to minimize the distortion included in the output signal e of the power amplifier 103, the appropriate phase correction amount and amplitude correction amount change according to the power supply voltage applied to the power amplifier 103 and the amplitude of the input signal a. Therefore, the characteristics of the modulation signal correction unit 111 have the characteristics shown in FIG.

In this way, the phase and amplitude of the input signal a can be corrected according to the power supply voltage of the power amplifier 103 and the amplitude of the input signal a, and the distortion included in the output signal e of the power amplifier 103 can be reduced to the maximum. J

[0044] When the input signal a is an intermediate frequency (IF) band signal, the transmission unit 102 may include a frequency conversion circuit. In addition, a band-pass filter may be included to suppress unwanted radiation components that accompany frequency conversion. In either case, the functions characteristic of the present invention can be realized in the same manner.

[0045] Further, one or more of the! / And the deviation of the amplitude detection unit 104, the amplitude signal correction unit 105, and the modulation signal correction unit 111 shown in the present embodiment may be a circuit using digital signal processing. Achieving power S At this time, if the above block is realized by a circuit using digital signal processing, the apparatus size can be reduced. Even when digital signal processing is used, the functions characteristic of the present invention can be similarly realized.

[0046] When one or more of the amplitude detection unit 104, the amplitude signal correction unit 105, and the modulation signal correction unit 111 are realized using digital signal processing, the transmission device 100 uses a digital-analog converter. Including. In addition, the transmission unit 102 may include a low-pass filter for removing image components associated with digital-analog conversion. The transmission unit 102 may include a frequency conversion circuit. In addition, spurious components that accompany frequency conversion. A band pass filter may be included to suppress the minutes. In either case, the functions characteristic of the present invention can be realized in the same way.

[0047] When the modulation signal correction unit 111 is configured using digital signal processing, the phase and amplitude can be corrected at a time by multiplying the input signal a by a complex number. In this case, the modulation signal phase correction unit 304 and the modulation signal amplitude correction unit 305 can be realized by a single block. Further, the phase correction coefficient calculation unit 406 and the amplitude correction coefficient calculation unit 407 can be realized by a single block for calculating a complex correction coefficient.

[0048] In addition, any one or both of the transmission unit 102 and the amplitude signal correction unit 105 described in the present embodiment may include a delay unit that delays an input signal. Since the above block includes a delay unit that includes an appropriate delay amount, the power supply voltage in the power amplifier 103 and the timing of the high-frequency signal can be accurately matched, and distortion included in the output signal e of the power amplifier 103 can be minimized. It is possible to

As described above, according to the present embodiment, transmission apparatus 100 has power supply voltage control unit 106 that controls the applied power supply voltage of the power amplifier in accordance with the amplitude component of the modulation signal, and inputs of power supply voltage control unit 106. And an amplitude signal correction unit 105 that is provided in a stage and corrects the amplitude width between the maximum amplitude and the minimum amplitude of the amplitude component to be small and further removes a high frequency component from the corrected amplitude component.

[0050] By doing this, the amplitude width between the maximum amplitude and the minimum amplitude of the amplitude component can be reduced, and the band can be narrowed by removing the high frequency component. Range and bandwidth requirements can be relaxed. For this reason, it is possible to use a small and inexpensive power supply voltage control unit 106, which can reduce the price of the transmitter 100 using the EER method and increase the power efficiency. Touch with power.

[0051] The amplitude signal correction unit 105 includes a low amplitude component limiting unit 203 that corrects the amplitude component by amplifying the amplitude of the portion of the amplitude component that is less than the threshold value to the threshold value, and the corrected amplitude component. And a low-pass filter unit 204 for removing high-frequency components from the filter.

[0052] By doing this, the amplitude of the amplitude component that is less than the threshold is reduced to the threshold. Therefore, the amplitude width between the maximum amplitude and the minimum amplitude in the input signal of the amplitude signal correction unit 105 can be reduced, and the high frequency component is removed from the corrected amplitude component. The bandwidth of the input signal can be reduced.

[0053] In addition, transmitter 100 is provided at the input stage of power amplifier 103, and the amplitude and phase of the modulation signal are corrected based on the amplitude component of the modulation signal and the applied power supply voltage of power amplifier 103. Further, a modulation signal correction unit 111 is provided.

[0054] By doing this, the amplitude and phase of the modulation signal that is the input signal of the power amplifier 103 are corrected based on the amplitude component of the modulation signal and the applied power supply voltage of the power amplifier 103. It is possible to compensate for a deviation from a desired power value and phase in the output signal of the power amplifier 103 that may occur.

[Embodiment 2]

FIG. 11 is a block diagram showing a configuration of transmitting apparatus 500 according to Embodiment 2 of the present invention. In order to correct the difference between the output signal (target output signal) of the desired power amplifier 103 and the actual output signal, the transmission device 500 calculates a correction coefficient in the amplitude phase correction process according to the difference. Adjust the characteristics.

[0056] As shown in the figure, transmitting apparatus 500 is connected to power amplifier 103 and includes force-pla section 501 that extracts a part of the output signal of power amplifier 103, and output of force-pla section 501 connected to force-pla section 501. Receiving unit 502 that converts the signal into a form comparable to input signal a, and correction using the output signal of receiving unit 502 connected to receiving unit 502 and input unit 101 and input signal a input from input unit 101 A correction characteristic updating unit 503 that updates coefficient calculation characteristics and a transmission unit 504 that is connected to the input unit 101 and outputs a high-frequency signal b from the input signal a are input. Transmitting section 504 is connected to input signal terminal 101 and correction characteristic updating section 503, and corrects the phase and amplitude of input signal a input from input section 101 according to a predetermined correction coefficient calculation characteristic and A modulation signal correction unit 511 that sequentially adjusts coefficient calculation characteristics according to the output of the correction characteristic update unit 503 is included.

[0057] Receiving section 502 performs the reverse process when transmitting section 504 and power amplifier 103 operate under ideal conditions. When the transmission unit 504 and the power amplifier 103 operate ideally, distortion included in the power amplifier 103 is canceled by the amplitude phase correction processing in the transmission unit 504. The That is, when the transmission unit 504 and the power amplifier 103 operate ideally, the signal level of the input signal a input from the input unit 101 is converted into the output signal of the power amplifier 103, and the transmission unit 504 and the power amplifier 103 are converted. The signal contains a certain amount of signal delay and a certain amount of phase rotation. Therefore, receiving section 502 performs signal level conversion, signal phase conversion, and signal delay adjustment. The signal thus obtained can be compared with the input signal a by the correction characteristic updating unit 503, that is, a signal having the same signal level, signal phase, and signal delay as the input signal a corresponding to the actual output signal of the power amplifier 103. It has become.

The correction characteristic updating unit 503 is configured to detect the difference in amplitude and phase between the output signal of the reception unit 502 corresponding to the actual output signal of the power amplifier 103 and the input modulation signal (that is, the power amplifier 103 The distortion included in the actual output power is calculated, and the correction coefficient calculation characteristic in the modulation signal correction unit 511 is adjusted based on the difference regarding the amplitude and phase. The correction characteristic updating unit 503 calculates a correction coefficient calculation characteristic that minimizes the difference based on the difference regarding the amplitude and phase, and is set in the modulation signal correction unit 511 at the present time with the calculated correction coefficient calculation characteristic. Update the correction coefficient calculation characteristics.

As shown in FIG. 12, the correction characteristic updating unit 503 includes a comparison unit 604 that detects a difference regarding amplitude and phase, and an applied power supply voltage and modulation of the power amplifier 103 at the time of detection by the comparison unit 604. The correction coefficient calculation unit 605 for calculating the correction characteristic (correction coefficient calculation characteristic) corresponding to the signal and the correction characteristic (correction coefficient calculation) of the modulation signal correction unit 511 using the calculated correction characteristic (correction coefficient calculation characteristic) And a correction coefficient updating unit 606 for updating the characteristics).

The comparison unit 604 calculates a difference regarding the amplitude and phase between the output signal of the reception unit 502 corresponding to the actual output signal of the power amplifier 103 and the input modulation signal. The difference regarding the amplitude and phase obtained in this way corresponds to the difference between the target output signal of the power amplifier 103 and the actual output signal. The difference related to the amplitude and phase is output to the update correction coefficient calculation unit 605 in relation to the input modulation signal and the power supply voltage of the power amplifier 103 at that time.

The update correction coefficient calculation unit 605 calculates a correction coefficient based on the difference regarding the amplitude and the phase from the comparison unit 604 and the power supply voltage of the power amplifier 103 so that the difference regarding the amplitude and the phase is minimized. Calculate the characteristics. The calculated correction factor calculation characteristic is the ratio Similar to the comparison unit 604, the input modulation signal and the power supply voltage of the power amplifier 103 at that time are related and output to the correction coefficient update unit 606.

The correction coefficient update unit 606 uses the correction coefficient calculation characteristic calculated by the update correction coefficient calculation unit 605 as the input modulation signal from the update correction coefficient calculation unit 605 and the power source of the power amplifier 103 at that time. Temporarily hold in association with the voltage. The correction coefficient updating unit 606 outputs the correction coefficient calculation characteristics accumulated after the previous output, and the input modulation signal and the power supply voltage of the power amplifier 103, which are associated with the correction coefficient calculation characteristics, at predetermined time intervals. Then, the correction coefficient calculation characteristic in the modulation signal correction unit 511 is updated.

Next, the operation of transmitting apparatus 500 having the above configuration will be described.

[0064] In receiving section 502, a signal having the same signal level, signal phase, and signal delay as input signal a corresponding to the actual output signal of power amplifier 103 is formed.

[0065] In correction characteristic updating section 503, based on the difference in amplitude and phase between the output signal of receiving section 502 corresponding to the actual output signal of power amplifier 103 and input signal a (input modulation signal), An update correction coefficient calculation characteristic for updating the correction coefficient calculation characteristic of the modulation signal correction unit 511 is calculated. The correction characteristic updating unit 503 calculates correction coefficient calculation characteristics that minimize the difference in amplitude and phase, in other words, between the target output signal of the power amplifier 103 and the actual output signal. Correction coefficient calculation characteristics that minimize the difference in amplitude and phase are calculated. The calculated correction coefficient calculation characteristic is reflected in the modulation signal correction unit 511.

Specifically, in correction characteristic updating section 503, comparison section 604 compares output signal e of power amplifier 103 with input signal a, and calculates the difference in association with input signal a. The update correction coefficient calculation unit 605 uses the difference calculated by the comparison unit 604 to calculate a correction coefficient that minimizes the difference between the output signal e and the input signal a in association with the input signal a. The correction coefficient update unit 606 holds the correction coefficient calculated by the update correction coefficient calculation unit 605 in association with the input signal a. Further, after a sufficient time has elapsed, the correction coefficient updating unit 606 outputs the held correction coefficient to the output terminal 603, and updates the correction characteristic of the modulation signal correction unit 511.

[0067] Thus, even when the characteristics of the power amplifier 103 change due to the operating environment, aging deterioration, etc. Therefore, it is possible to update the correction coefficient calculation characteristic of the modulation signal correction unit 511 appropriately, that is, to reduce the distortion included in the output signal e of the power amplifier 103. In addition, since the correction coefficient calculation characteristic is periodically updated, it is possible to update the correction coefficient calculation characteristic appropriately following the characteristic change of the power amplifier 103. As a result, the transmission apparatus 500 can be stably operated.

[0068] Note that the correction characteristic updating unit 503 can be realized using a digital signal processor (DSP). At this time, since the correction characteristic updating unit 503 needs the output signal b converted into a digital signal, the receiving unit 502 includes an analog-digital converter and a frequency conversion circuit. Similarly, since the input signal a converted into a digital signal is required, an analog / digital converter that converts the input signal a into a digital signal is required. However, when the input signal a is a digital signal and input to the input unit 101, a converter for converting the input signal a into a digital signal is not necessary.

[0069] In addition, in the update correction coefficient calculation unit 605, LMS (Least Mean Square) algorithm or RMS (Recursive Mean Square) algorithm is used as an algorithm for calculating the correction coefficient calculation characteristic from the difference between the input signal a and the output signal e. There is. In addition, there is a genetic algorithm as an algorithm for calculating the correction coefficient calculation characteristic directly without using the difference. Regardless of which algorithm is used, it is possible to calculate a correction coefficient that reduces the distortion included in the output signal e.

As described above, according to the present embodiment, the transmitter 500 receives from the output signal of the power amplifier 103 the input signal a input from the input unit 101 corresponding to the output signal, and the signal level. Based on the difference in amplitude and phase between the reception unit 502 that calculates a signal with the same signal phase and signal delay, and the signal calculated by the input signal a and the reception unit 502, the correction characteristics of the modulation signal correction unit 51 1 1 And a correction characteristic updating unit 503 for adjustment.

In this way, even when the characteristics of the power amplifier 103 change due to the operating environment, aging deterioration, or the like, the correction characteristics (correction coefficient calculation characteristics) of the modulation signal correction unit 511 are appropriately set, that is, the power amplifier 103 Can be updated to reduce distortion contained in the output signal.

[0072] The embodiments of the present invention have been described above. As is clear from the above, transmission according to the present invention The apparatus can be mounted on a communication terminal apparatus and a base station apparatus in a mobile communication system, thereby providing a communication terminal apparatus, a base station apparatus, and a mobile communication system having the same operational effects as described above. be able to.

Note that each functional block used in the description of each of the above embodiments is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. Here, it may be called IC, system LSI, super LSI, or ultra LSI, depending on the difference in power integration as LSI. Also, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Field programmable gate arrays (FPGAs) that can be programmed after LSI manufacturing and reconfigurable processors that can reconfigure the connection and settings of circuit cells inside the LSI may be used. Furthermore, if integrated circuit technology that replaces LSI emerges as a result of advances in semiconductor technology or other derived technologies, it is naturally possible to integrate functional blocks using this technology. For example, the possibility of applying technology is possible.

Yes

[0074] December 2006 Patent application 2006-337026 The contents of the description, drawings and abstract contained in this application are all incorporated herein by reference.

Industrial applicability

[0075] The transmission device of the present invention has the effects of reducing the cost by relaxing the requirements for the power supply voltage control unit and increasing the power efficiency, and particularly uses the EER method. This is useful as a transmission device.

Claims

The scope of the claims

[1] a power amplifier that amplifies an input modulation signal according to an applied power supply voltage;

A power supply voltage control unit for controlling an applied power supply voltage of the power amplifier according to an amplitude component of the modulation signal;

An amplitude component correction unit provided at an input stage of the power supply voltage control unit, correcting the amplitude width between the maximum amplitude and the minimum amplitude of the amplitude component to be small, and further removing a high frequency component from the corrected amplitude component;

A transmission apparatus comprising:

[2] The amplitude component correction means includes:

Low amplitude component limiting means for correcting the amplitude component by amplifying the threshold of the amplitude component and the amplitude of the portion below the value to the threshold and value;

The transmission device according to claim 1, further comprising: a low-pass filter that removes a high-frequency component from the corrected amplitude component.

[3] The transmission according to claim 1, further comprising modulation signal correction means provided at an input stage of the power amplifier and configured to correct the amplitude and phase of the modulation signal based on the amplitude component and the applied power supply voltage. apparatus.

[4] From the output signal of the power amplifier, calculation means for calculating a signal corresponding to the output signal and equivalent to the modulation signal input to the modulation signal correction means;

4. The transmission apparatus according to claim 3, further comprising: an adjustment unit that adjusts a correction characteristic of the modulation signal correction unit based on a difference in amplitude and phase between the modulation signal and the signal calculated by the calculation unit. .

[5] The adjusting means includes

Detecting means for detecting a difference related to the amplitude and phase;

Correction characteristic calculation means for calculating the correction characteristic corresponding to the applied power supply voltage and the modulation signal at the time of detection by the detection means;

Correction characteristic updating means for updating the correction characteristic of the modulation signal correction means with the calculated correction characteristic;

The transmitter according to claim 4, comprising: Modulation signal correction means for correcting the amplitude and phase of the modulation signal input to the power amplifier so as to compensate for a deviation from a target value in the output signal of the power amplifier caused by the processing of the amplitude component correction means; The transmission device according to claim 1, further comprising: