JP2007318358A - Wireless signal transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless signal transmitter adopting polar modulation whereby highly efficient power amplification can be performed even when a signal band is broadbanded. <P>SOLUTION: When a baseband signal generator 101 receives a transmission data signal S100, digital signals b(-N), b(-N+1), ..., b(N) from which the transmission data signal S100 is separated for every frequency are inputted to an IFFT section 111 in parallel. On the other hand, 2N sets of multipliers 112 extracts correction coefficients a(-N), a(-N+1), ..., a(N) from a correction coefficient storing section 113 and multiply individual correction coefficients for the respective digital signals b(-N), b(-N+1), ..., b(N). In this case, the multipliers multiply correction coefficients with a small absolute value with digital signals with a low frequency component, and multiply correction coefficients with a greater absolute value according to digital signals with a higher frequency component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio signal transmitter used in a radio signal transmission system such as mobile communication and a wireless LAN, and more particularly, radio signal transmission for generating a vector modulation wave by performing polar modulation with an amplitude modulation signal and a phase modulation signal. Related to the machine.

  In the future, the transmission band of wireless signals in mobile communication (cellular) communication, wireless LAN, and the like is gradually expanding from several hundred kHz to several tens of MHz. Thereby, the power consumption of the power amplifier (PA: Power-Amplifier) of the mobile terminal increases, and as a result, the battery life of the mobile terminal decreases or the heat dissipation increases. Therefore, a power amplifier used in a portable terminal is required to amplify a high-speed / wideband signal with low distortion and high efficiency.

  Thus, polar modulation has attracted attention as a technique for performing modulation and amplification by increasing the efficiency of a transmission signal of a portable terminal. Such polar modulation is also called EER (Envelope-Elimination-Restoration). The input signal is separated into a phase component and an amplitude component, and the signal wave of the amplitude component is used as a power source of the phase modulation amplifier, and the phase modulation signal and the amplitude modulation are used. This is a technique for generating a vector modulation wave by modulating and synthesizing a signal.

FIG. 11 is a basic configuration diagram of a general polar modulation circuit. The basic configuration of such a polar modulation circuit is disclosed in Patent Document 1, for example. In FIG. 11, when baseband signals I (t) and Q (t) are output from the baseband signal generator 1, the polar coordinate converter 2 converts the baseband signals I (t) and Q (t) into amplitude components r. The signal is decomposed into a signal of (t) and a signal of phase component φ (t). Then, the signal of the amplitude component r (t) passes through the amplitude modulation signal amplifier 3 and is then input to the power supply terminal of the power amplifier 5 at the final stage to perform power supply voltage modulation. On the other hand, the signal of the phase component φ (t) is generated by the phase modulator 4 after generating an RF phase modulation signal (cos (2πf _C t + φ (t))) having the center frequency f _C of the carrier (carrier wave). By inputting the phase modulation signal (cos (2πf _C t + φ (t))) to the power amplifier 5 in the final stage, the signal of the amplitude component r (t) and the RF phase modulation signal (cos (2πf _C t + φ (t))) ) And are multiplied. Thus, the power amplifier 5 can generate and output a high-power radio signal (r · cos (2πf _C t + φ (t))).

  Such polar modulation allows the power amplifier 5 to perform a switching operation in a non-linear region, so that very high-efficiency power amplification can be performed. Further, by using a voltage-controlled oscillator (VCO) as the phase modulator 4, extra noise outside the signal band can be reduced. Therefore, the polar modulation circuit does not require a SAW (Surface Acoustic Wave) filter, which is an intermediate frequency filter required in the conventional quadrature modulation method or the like. Since such a SAW filter has a size of several mm square, it is one of the parts that should be removed as much as possible in order to reduce the size of the mobile phone. That is, polar modulation has attracted attention as one of amplification methods for modulating a transmission signal in a mobile terminal with high efficiency.

In addition, as a method for widening the phase modulator using a VCO in the polar modulation circuit, the signal components outside the loop band and the outside of the loop band of the PLL (Phase Locked Loop) circuit are separated. A technique for inputting directly to the VCO without using a loop control circuit is also disclosed. As a result, wideband phase modulation is possible without the signal band being limited by the loop band of the phase modulator (see, for example, Patent Document 2).
JP 2005-244950 A JP 2005-287010 A

  However, the polar modulation method as described in Patent Document 1 is an effective method as a high-efficiency amplification method, but the amplification characteristic deteriorates in a wideband signal. This cause depends on the frequency characteristics of the components constituting the amplitude modulation signal amplifier 3 and the phase modulator 4, so that it is difficult to increase the bandwidth of the amplitude modulation signal amplifier 3 and the bandwidth of the phase modulator 4. To do. That is, in the method of widening the amplitude modulation by the polar modulation method disclosed in the above-mentioned Patent Document 1, the amplitude modulation signal is separated into a low frequency component and a high frequency component, and each switching regulator or linear regulator is used. Since the band signal of the components (that is, the low frequency component and the high frequency component) is efficiently amplitude-modulated, there is a limit to amplifying both the low frequency component and the high frequency component of the amplitude modulation signal with high efficiency. On the other hand, the polar modulation method as in Patent Document 2 described above enables wide-band phase modulation without limiting the signal band by the loop band of the phase modulator, but when the transmission signal band further increases As a result, power consumption increases and high efficiency cannot be realized.

  In other words, since the transmission signal bandwidth will increase further in the future, it is expected that the polar modulation schemes disclosed in Patent Document 1 and Patent Document 2 will not be able to cope with maintaining high efficiency over a wide band. The For example, even if it becomes possible to widen the power supply voltage modulation, it becomes impossible to maintain high efficiency by causing further increase in power consumption, and as a result, the effect of polar modulation is diminished.

  The present invention has been made in view of this point, and an object of the present invention is to provide a radio signal transmitter based on polar modulation that can perform high-efficiency power amplification even when the signal band becomes wide.

  The radio signal transmitter according to the present invention has a baseband signal generator having an inverse fast Fourier transform unit with 2N input points (N is a natural number) and an amplitude of a baseband signal generated by the baseband signal generator. Polar coordinate converter that separates modulation signal and phase modulation signal; amplitude modulation signal amplifier that amplifies amplitude modulation signal; phase modulator that generates radio frequency phase modulation signal from phase modulation signal; and biasing amplitude modulation signal And a power amplifier that amplifies the power of the radio frequency phase modulation signal, and the baseband signal generator corrects the level of the input signal input to the inverse fast Fourier transform (IFFT). The structure provided with a means is taken.

  According to the radio signal transmitter of the present invention, the IFFT parallel input signal of the baseband signal generator having the inverse fast Fourier transform unit (IFFT unit) is multiplied by a correction coefficient having a different value for each frequency. The frequency response characteristic deterioration of the phase modulator and power amplifier constituting the polar modulator can be corrected. As a result, it is possible to realize a polar modulation type radio signal transmitter capable of performing highly efficient power amplification over a wide band.

<Summary of invention>
When a parallel signal is input to the inverse fast Fourier transform unit (IFFT unit) included in the baseband signal generator, the wireless signal transmitter of the present invention multiplies each parallel signal by an individual correction coefficient. Yes. That is, since the parallel signal input to the IFFT unit is separated from the low frequency component to the high frequency component, the parallel signal of the low frequency component is multiplied by a correction coefficient having a small absolute value, and the high frequency component is sequentially added. As the parallel signal is obtained, a correction coefficient having a larger absolute value is multiplied. Each correction coefficient at this time is set to a value that suppresses deterioration of the frequency response characteristic of the output signal in the power amplifier. As a result, frequency response characteristics in polar modulation can be corrected for each frequency band. As a result, even when the signal band becomes wide, high-efficiency power amplification can be performed, and widening is possible. .

  Hereinafter, several embodiments of the wireless signal transmitter of the present invention will be described in detail with reference to the drawings. In the drawings used in the embodiments, the same components are denoted by the same reference numerals, and redundant description is omitted as much as possible.

<Embodiment 1>
Hereinafter, the radio signal transmitter according to the first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a radio signal transmitter according to Embodiment 1 of the present invention. First, the configuration of the wireless signal transmitter shown in FIG. 1 will be described. The wireless signal transmitter includes a baseband signal generator 101 that receives a transmission data signal S100 and generates a baseband signal, a polar coordinate converter 102 that receives a baseband signal and generates a polar modulation signal, and a separated amplitude. An amplitude modulation signal amplifier 103 that amplifies the modulation signal, a phase modulator (VCO) 104 that converts the separated phase signal into a phase modulation signal in a radio frequency (RF) frequency band, and a phase modulation signal using the amplitude modulation signal as a power source A power amplifier (PA: Power-Amplifier) 105 that performs power amplification, and a correction coefficient changing unit 114 that changes the value of the correction coefficient according to environmental changes such as temperature.

  The baseband signal generator 101 also multiplies each of the parallel signals input to the inverse fast Fourier transform unit (IFFT unit) 111 that performs inverse Fourier transform on the transmission data signal S100 and the parallel signal input to the IFFT unit 111 by a plurality of individual correction coefficients. And a correction coefficient storage unit 113 that stores a plurality of correction coefficients to be multiplied by each of the parallel signals.

  Next, the operation of the wireless signal transmitter shown in FIG. 1 will be described. When the baseband signal generator 101 receives the transmission data signal S100 and outputs the output signals I (t) and Q (t) of the baseband signal, the polar coordinate converter 102 outputs the output signals I (t) and Q ( From t), a polar modulation signal of amplitude signal component r (t) and phase signal component φ (t) is generated. The signal of the amplitude signal component r (t) is amplified by the amplitude modulation signal amplifier 103 and then input to the power input terminal of the power amplifier (PA) 105. The power input terminal refers to a drain terminal or an emitter terminal in an FET or transistor.

On the other hand, the signal of the phase signal component φ (t) is input to the phase modulator (VCO) 104, and the phase modulation signal (cos (2πf) in the radio signal frequency band (RF band) which is the center frequency f _C of the carrier (carrier wave). _C t + φ (t))) is generated, and this phase modulation signal is input to the power amplifier 105. Then, the phase modulation signal (cos (2πf _C t + φ (t))) in this radio signal frequency band is input to the power amplifier 105 in the final stage, whereby the amplitude signal component r (t) and the phase modulation signal (cos) (2πf _C t + φ (t))). As a result, the power amplifier 105 can generate and output a desired high-power wireless signal (r · cos (2πf _C t + φ (t))).

  The above is an outline of the configuration and operation of a general polar modulation system. The baseband signal generator 101 of the present invention further includes an inverse fast Fourier transform unit (IFFT unit) 111, and this IFFT unit 111. Signal correction means for performing signal processing to correct response characteristic deterioration at high frequencies of the polar modulation signal (that is, the signal of the amplitude signal component r (t) and the signal of the phase signal component φ (t)) before Provide. This signal correction means includes a correction coefficient storage unit 113 that stores a plurality of correction coefficients to be multiplied to each of parallel signals from a low frequency component to a high frequency component input to the IFFT unit 111, and a correction coefficient according to environmental changes such as temperature. The correction coefficient changing unit 114 that changes the value of the signal and the plurality of multiplying units 112 that multiply each of the parallel signals input to the IFFT unit 111 by individual correction coefficients. In FIG. 1, the signal correction means is not displayed.

Next, a baseband signal correction method by the signal correction means and its principle will be described. The number of points of IFFT unit 111 is 2N (where N is a natural number), and a digital signal (hereinafter referred to as an input digital signal) of transmission data signal S100 that is an input signal of IFFT unit 111 is represented by b (−N) to b (N ), The output digital signal g (m) (where m is −N, −N + 1... + N) of the IFFT unit 111 is defined as the following equation (1).

  FIG. 3 is a characteristic diagram showing the relationship between the input digital signal b (n) and the frequency band (f) input to the IFFT unit 111 of the wireless signal transmitter shown in FIG. 1, and FIG. It is a characteristic view which shows the relationship between the output digital signal g (m) output from IFFT section 111 of the shown radio signal transmitter, and time (t). That is, n in the input digital signal b (n) in FIG. 3 represents frequency (f), and m in the output digital signal g (m) in FIG. 4 represents time. In other words, the input digital signal b (n) means a signal component for each frequency of the transmission data signal S100 input to the baseband signal generator 101.

  That is, as can be seen from FIG. 3, the signal level of the input digital signal b (n) of the IFFT unit 111 changes depending on the frequency (f). Further, as can be seen from FIG. 4, the signal level of the output digital signal g (m) of the IFFT unit 111 changes on the time axis substantially in proportion to the input digital signal b (n).

  FIG. 5 is a diagram showing frequency response characteristics of the input signal amplitude from the polar coordinate converter 102 to the power amplifier (PA) 105 of the radio signal transmitter shown in FIG. Further, FIG. 6 is a diagram showing the frequency response characteristics of the output signal amplitude of the power amplifier (PA) 105 in the wireless signal transmitter shown in FIG. As shown in FIG. 5, even when the frequency characteristic of the input signal amplitude of the power amplifier (PA) 105 is flat, the output signal amplitude of the power amplifier (PA) 105 has a low frequency as shown in FIG. It declines at high places. The reason is that the frequency characteristics of the components constituting the amplitude modulation signal amplifier 103 and the phase modulator (VCO) 104 are deteriorated.

Therefore, the frequency response characteristic of the output signal amplitude in the power amplifier (PA) 105 shown in FIG. 6 is measured in advance, and each amplitude value of the frequency response characteristic when the signal bandwidth 2N / T ₀ is divided into 2N is obtained. , F (−N), f (−N + 1)... F (+ N). At this time, the output digital signal g1 (m) of the power amplifier (PA) 105 is expressed by the following equation (2) with respect to the output digital signal g (m) of the IFFT unit 111.

  FIG. 7 shows the frequency characteristic b1 (n) of the output digital signal g1 (m) before correction of the power amplifier (PA) 105 in the radio signal transmitter shown in FIG. That is, the frequency characteristic b1 (n) = f (n) · b (n) of the power amplifier (PA) 105 before correction is indicated by a solid line. The dotted line shows the frequency characteristics of the input digital signal b (n). As can be seen from this characteristic diagram, the amplitude of the high frequency component of the frequency characteristic b1 (n) before correction is lower than the frequency characteristic of the input digital signal b (n).

Next, a specific correction method will be described. From the output signal amplitude f (n) of the power amplifier (PA) 105 measured in advance, correction coefficients a (−N) to a (N) are set to a (n) = 1 / f (n) (where n = −N To + N). Next, in the multiplication unit 112, 2N correction coefficients a (−N) to a (N) are individually applied to 2N input signals b (−N) to b (N) of the IFFT unit 111, respectively. Multiply. The output digital signal g1 (m) of the power amplifier at this time is expressed by the following equation (3).

  That is, the relationship between the output digital signal g (m) of the IFFT unit 111 and the output digital signal g1 (m) of the power amplifier (PA) 105 is g1 (m) = g (m), and the input digital signal b (n ) And the frequency characteristic b1 (n) of the power amplifier (PA) 105 are b1 (n) = b (n), and it can be seen that the frequency characteristic deterioration can be compensated. FIG. 8 shows the frequency characteristic b1 (n) of the output digital signal g1 (m) after correction of the power amplifier (PA) 105 in the radio signal transmitter shown in FIG.

  As described above, when the amplitude amplification of the polar modulation or the deterioration of the high frequency characteristics in the phase modulator 104 occurs, the multiplication unit 112 multiplies the input digital signal b (n) by the correction coefficient a (n). The deterioration of characteristics can be improved. The correction coefficient a (n) is stored in the correction coefficient storage unit 113 and can be arbitrarily changed by the correction coefficient changing unit 114. For example, when a change occurs in the environmental temperature, the correction coefficient a (n) is corrected to an optimum value so that the correction coefficient changing unit 114 performs temperature compensation.

  When the optimum correction coefficient a (n) varies among the devices of the amplitude modulation signal amplifier 103 and the phase modulator 104, individual adjustment of the correction coefficient a (n) is required in the manufacturing process. In addition, when the value of the optimum correction coefficient varies depending on the environmental temperature or the like, there may be a case where a function for adjusting the correction coefficient corresponding to the temperature is required. However, even in these cases, the adjustment circuit design and the adjustment process become extremely easy if the correction coefficient changing unit 114 is present.

  All the signal correction processes as described above are performed in the digital processing circuit of the baseband signal generation unit 101 (that is, the signal correction unit including the correction coefficient storage unit 113, the correction coefficient change unit 114, and the multiplication unit 112). In the amplitude modulation signal amplifier 103 and the phase modulator 104, since the signal level on the high frequency side is usually lower than that on the low frequency side, the absolute value of n increases (that is, as the frequency increases). By setting the absolute value of the correction coefficient a (n) to be large, it is possible to appropriately correct the deterioration of the frequency characteristic. As a result, the amplitude modulation signal amplifier 103 and the phase modulator 104 can be widened, and as a result, the wireless signal transmitter can be widened.

  In recent years, digital processing has been accelerated, and for example, inverse fast Fourier transform (IFFT) has been used to generate and demodulate wideband signals such as OFDM (Orthogonal Frequency Division Multiplexing). There is no need to add a new IFFT unit in order to perform the broadband correction as described above. This is one of the great advantages of the radio signal transmitter according to the present invention. That is, in the conventional method, a new circuit configuration is added to increase the bandwidth, or power consumption is increased due to the addition of the circuit configuration. However, in the radio signal transmitter of the present invention, the baseband signal is increased. By simply adding and changing a part of the digital processing of the generator 101, the bandwidth can be increased, and a new circuit becomes unnecessary.

  In the above description, only a decrease in the high-frequency response of the signal amplitude is assumed as the characteristic deterioration at high frequencies of the amplitude modulation signal amplifier 103 and the phase modulator 104. However, when the frequency becomes high, the group delay variation (that is, phase variation) ) Also causes signal degradation. Therefore, in the radio signal transmitter according to the present embodiment, by making the correction coefficient a (n) a complex number, it is possible to compensate or suppress phase fluctuations at the same time, so that further performance including the phase in the high frequency band can be achieved. Improvements can be made.

  Next, an example of a method for setting the correction coefficient a (n) in consideration of characteristic deterioration due to phase fluctuation will be described. FIG. 9 is a diagram showing frequency response characteristics of the input signal phase from the polar coordinate converter 102 to the power amplifier (PA) 105 of the wireless signal transmitter shown in FIG. Further, FIG. 10 is a diagram showing the frequency response characteristics of the output signal phase of the power amplifier (PA) 105 in the radio signal transmitter shown in FIG. That is, FIG. 10 shows the frequency characteristic of the input signal phase from the polar coordinate converter 102 to the power amplifier (PA) 105 when the frequency characteristic of the input signal phase is flat as shown in FIG.

That is, the phase fluctuation value in the power amplifier (PA) 105 is measured in advance, and the fluctuation value of the phase frequency response characteristic when the signal bandwidth 2N / T ₀ is divided into 2N is expressed as θ (−N), θ (−N +)... Θ (+ N). Note that the frequency characteristic of the amplitude of the output digital signal g (m) of the IFFT unit 111 is as shown in FIG.

At this time, the frequency component b2 (n) of the output digital signal of the power amplifier 105 before correction is
b2 (n) = b (n) · f (n) · exp (iθ (n)).
When the correction coefficient a (n) is a (n) = 1 / (f (n) · exp (iθ (n))), the frequency component b2 (n) of the output signal after correction is expressed by the following equation ( It becomes like 4).
b2 (n) = (b (n) a (n)) f (n) .exp (iθ (n)) = b (n) (4)

  Therefore, it can be seen that it is possible to compensate for frequency characteristic degradation including phase fluctuation.

<Embodiment 2>
FIG. 2 is a block diagram showing a part of the configuration of the radio signal transmitter according to Embodiment 2 of the present invention. In FIG. 2, the baseband signal generator 101 and the correction coefficient changing unit 114 are omitted in the second embodiment, but their internal configurations are the same as those of the radio signal transmitter in the first embodiment shown in FIG. is there. That is, in FIG. 2, only the configuration after the stage where the polar coordinate converter 102 generates the amplitude modulation signal r (t) and the phase modulation signal φ (t) after the I (t) signal and the Q (t) signal are generated. It is shown.

  The configuration newly added to the wireless signal transmitter according to the second embodiment is to remove the broadband components of the amplitude modulation signal r (t) and the phase modulation signal φ (t) that are the outputs of the polar coordinate converter 102. A first low-pass filter 115 and a second low-pass filter 116 have been added. That is, it is expected that high frequency components outside the signal band of the amplitude modulation signal r (t) and the phase modulation signal φ (t) are increased more than necessary by the frequency correction described in the first embodiment. Therefore, by inserting the first low-pass filter 115 and the second low-pass filter 116 in front of the amplitude modulation signal amplifier 103 and the phase modulator 104, unnecessary components outside the signal band can be further suppressed. .

  The low-pass filter may be inserted into either the amplitude modulation signal or the phase signal, or the first low-pass filter 115 and the second low-pass filter 116 may be inserted into the amplitude modulation signal and the phase signal, respectively. Also good. When the in-band fluctuation of the low-pass filter cannot be ignored, the above-described correction coefficient a (n) needs to be optimized including the filter characteristics of the first low-pass filter 115 and the second low-pass filter 116. That is, it is necessary to optimize the correction coefficient a (n) after inserting the first low-pass filter 115 and the second low-pass filter 116.

  In the future, as the uplink signal transmission capacity of the wireless transmission system increases, the efficiency of the power amplifier of the mobile terminal decreases and the battery consumption increases. Therefore, polar modulation is attracting attention as a high-efficiency modulation method, but it is difficult to cope with a wide band of signals. Therefore, the wireless signal transmitter according to the present invention can be used for the next-generation mobile terminal because it can amplify even a wideband signal with low noise and high efficiency.

1 is a block diagram showing a configuration of a radio signal transmitter according to Embodiment 1 of the present invention. FIG. 3 is a block diagram showing a part of the configuration of a radio signal transmitter in Embodiment 2 of the present invention FIG. 3 is a characteristic diagram showing a relationship between an input digital signal input to the IFFT unit of the radio signal transmitter shown in FIG. 1 and a frequency band. FIG. 3 is a characteristic diagram showing a relationship between an output digital signal output from the IFFT unit of the wireless signal transmitter shown in FIG. 1 and time; The figure which shows the frequency response characteristic of the input signal amplitude from the polar coordinate converter of the radio | wireless signal transmitter shown in FIG. 1 to power amplifier (PA). The figure which shows the frequency response characteristic of the output signal amplitude of the power amplifier (PA) in the radio signal transmitter shown in FIG. The figure which shows the frequency characteristic of the output digital signal before correction | amendment of the power amplifier (PA) in the radio signal transmitter shown in FIG. The figure which shows the frequency characteristic of the output digital signal after correction | amendment of the power amplifier (PA) in the radio signal transmitter shown in FIG. The figure which shows the frequency response characteristic of the input signal phase from the polar converter of the radio signal transmitter shown in FIG. 1 to the power amplifier (PA) The figure which shows the frequency response characteristic of the output signal phase of the power amplifier (PA) in the radio signal transmitter shown in FIG. Basic configuration diagram of a typical polar modulation circuit

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Baseband signal generator 102 Polar coordinate converter 103 Amplitude modulation signal amplifier 104 Phase modulator (VCO)
105 Power amplifier (PA)
111 Inverse Fast Fourier Transform (IFFT) Unit 112 Multiplying Unit 113 Correction Coefficient Storage Unit 114 Correction Coefficient Changing Unit 115 First Low Pass Filter 116 Second Low Pass Filter I (t) I Signal Q (t) Q Signal r (t) Amplitude modulation signal φ (t) Phase modulation signal S100 Transmission data signal

Claims (7)

A baseband signal generator having an inverse fast Fourier transform unit with 2N input points (N is a natural number), and a baseband signal generated by the baseband signal generator is separated into an amplitude modulation signal and a phase modulation signal A polar coordinate converter, an amplitude modulation signal amplifier that amplifies the amplitude modulation signal, a phase modulator that generates a radio frequency phase modulation signal from the phase modulation signal, and the radio frequency phase modulation by biasing the amplitude modulation signal A wireless signal transmitter comprising a power amplifier for amplifying signal power,
The radio signal transmitter, wherein the baseband signal generator includes signal correction means for correcting a level of an input signal input to the inverse fast Fourier transform unit.   The signal correction means, when n is an integer from -N to N, 2N correction coefficients a () assigned to each of 2N parallel input signals b (n) input to the inverse fast Fourier transform means. The radio signal transmitter according to claim 1, further comprising a multiplication unit that multiplies each of the parallel input signals b (n) by n).   The radio signal transmitter according to claim 2, wherein the correction coefficient a (n) has an absolute value that increases as the parallel input signal b (n) changes from a low frequency component to a high frequency component.   The said signal correction means is further provided with the correction coefficient preservation | save part which preserve | saves the said correction coefficient a (n), and the correction coefficient change part which rewrites the said correction coefficient a (n), The claim 2 or Claim characterized by the above-mentioned. Item 4. The wireless signal transmitter according to Item 3.   The correction coefficient changing unit is configured to compensate the temperature change of at least one of the baseband signal generator, the polar coordinate converter, the amplitude modulation signal amplifier, the phase modulator, and the power amplifier. 5. The radio signal transmitter according to claim 4, wherein the absolute value of n) is changed.   6. The radio signal transmitter according to claim 1, further comprising a first low-pass filter that removes a signal out-of-band noise component between the polar coordinate converter and the amplitude modulation signal amplifier. .   The wireless signal transmitter according to claim 6, further comprising a second low-pass filter for removing an out-of-band noise component of a phase signal between the polar coordinate converter and the phase modulator.

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