JP4755069B2 - Transmitter - Google Patents

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JP4755069B2
JP4755069B2 JP2006301904A JP2006301904A JP4755069B2 JP 4755069 B2 JP4755069 B2 JP 4755069B2 JP 2006301904 A JP2006301904 A JP 2006301904A JP 2006301904 A JP2006301904 A JP 2006301904A JP 4755069 B2 JP4755069 B2 JP 4755069B2
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distortion component
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JP2008118552A (en
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裕康 佐野
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三菱電機株式会社
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  The present invention relates to a transmitter capable of suppressing a peak voltage of a modulation signal, and in particular, reduces out-of-band radiation generated by nonlinear amplitude limiting processing even when the peak voltage is suppressed. In particular, the present invention relates to a transmission apparatus that suppresses peak power and compensates for distortion.

  Non-Patent Document 1 below describes an example of a conventional transmission apparatus that can suppress the peak power of a modulated signal having a large peak power, such as a multicarrier modulation scheme. Hereinafter, a conventional transmission apparatus will be described with reference to FIG.

  FIG. 8 is a diagram showing a basic configuration of a transmission apparatus capable of reducing the peak power of a modulation signal of a conventional multicarrier modulation method. This conventional transmission apparatus includes a modulator 91, a clip unit 92, a filter unit 93, a frequency conversion unit 94, an amplifier 95, and an antenna 96.

  In the transmission apparatus having such a configuration, the modulator 91 performs modulation processing on transmission data that is an input signal. The output of the modulator 91 is input to the clip unit 92, and the clip unit 92 performs a clipping process for reducing peak power on the time waveform of the signal. Here, if the signal input for each sample to the clip unit 92 is x and the amplitude of clipping is A, the output signal y of the clip unit 92, which is a signal obtained by executing the clipping process, is expressed by the following equation (1). expressed.

  The output of the clip unit 92 is input to the filter unit 93. The filter unit 93 performs filtering on the input signal to suppress out-of-band radiation power generated by the nonlinear amplitude limiting process (clipping process) executed in the clip unit 92. The output of the filter unit 93 is input to the frequency conversion unit 94, and the frequency conversion unit 94 performs frequency conversion to a high frequency band. Then, the output of the frequency conversion unit 94 is input to the amplifier 95, and after the signal is amplified, it is transmitted via the antenna 96.

"Effects of Clipping and Filtering on the Performance of OFDM" IEEE Communications Letters, vol.2 No.5, p.131-133, May 1998

  By the way, in the signal subjected to multicarrier modulation, the peak power becomes very large with respect to the average power, and the spread of the amplitude distribution tends to increase as the number of carriers used increases. Therefore, when transmission is performed while suppressing distortion corresponding to this large peak power, it is necessary to use a linear region of the transmission amplifier, and it is necessary to set a large backoff. However, if a large back-off is set, there is a problem that the power efficiency of the amplifier is reduced.

  Further, it is possible to suppress the peak power by performing the clipping process as described in Non-Patent Document 1, but when the clipping process is executed, out-of-band radiation occurs. For this reason, generally, a technique of limiting the out-of-band radiation component by filtering the signal after execution of the clipping process is employed. However, since the distortion component in the band generated by the clipping process remains even after passing through the filter, there is a problem that the modulation accuracy deteriorates due to the distortion in the band when the suppression amount of the peak power is increased.

  In general, amplifiers have non-linear input / output characteristics related to amplitude and phase, and distortion compensation processing is required for amplifiers when they are used up to the amplifier saturation region in order to improve amplifier power efficiency. . However, when peak power suppression processing and distortion compensation processing are independent, the signal after peak power suppression processing is not backed by the nonlinear characteristics remaining in the distortion-compensated amplifier. There is a problem that it is necessary to increase the off-margin, resulting in a decrease in power efficiency.

  The present invention has been made in view of the above, and in a transmission device that transmits a modulated signal with a large peak power, it is possible to suppress the amount of modulation accuracy degradation while suppressing the peak power of the modulated signal, and An object of the present invention is to obtain a transmission device capable of reducing out-of-band radiation.

  In order to solve the above-described problems and achieve the object, the present invention provides a transmission apparatus including transmission signal generation means for executing a predetermined transmission signal generation process on a baseband digital modulation signal, The transmission signal generation means generates a transmission signal for the input signal based on a baseband digital modulation signal as an input signal and non-linear information indicating the input / output characteristics of the transmission signal generation means acquired in advance. A distortion component generation means for generating a distortion component outside the band generated when executing the processing, and an out-of-band generated by the distortion component generation means from the baseband digital modulation signal input to the distortion component generation means Distortion component subtracting means for subtracting the distortion component, wherein the transmission signal generating means is a digital modulation signal in the baseband band after the distortion component subtraction. And executes the transmission signal generation processing on.

  According to the present invention, based on the result of nonlinear processing performed in consideration of the nonlinear characteristic of the amplifier, the modulation signal to which the distortion compensation signal that can reduce the out-of-band distortion component generated when the amplifier passes is added. Since it is generated, there is an effect that the peak power can be suppressed using the characteristics of the amplifier while reducing distortion outside the band when the transmission signal is amplified.

  Embodiments of a transmission apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. For example, in the following description, a case where a modulation signal of a multicarrier modulation scheme is transmitted will be described, but the present invention is not limited to a modulation signal of a multicarrier modulation scheme.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a transmission apparatus according to a first embodiment of the present invention. This transmission apparatus includes a modulation unit 1, a distortion compensation signal generation / addition unit 2, a D / A conversion unit 3, a frequency conversion unit 4, an amplifier 5, and an antenna 6. The modulation unit 1 performs a modulation process on transmission data that is an input signal to generate a modulation signal. The distortion compensation signal generation / addition unit 2 generates a modulation signal to which a distortion compensation signal described later is added. Thereafter, the modulation signal to which the distortion compensation signal is added is converted into an analog signal by the D / A converter 3 and then input to the frequency converter 4. The frequency converter 4 converts the frequency of the input signal to a signal in the RF band, and the amplifier 5 amplifies the output signal from the frequency converter 4. The amplified signal is transmitted via the antenna 6.

  FIG. 2 is a diagram illustrating a configuration example of the distortion compensation signal generation / addition unit 2. FIGS. 3A and 3B show input / output characteristics of the amplifier (amplifier 5) on the transmission side, and show AM-AM characteristics and AM-PM characteristics, respectively. The transmission apparatus according to the present invention suppresses the peak power of the modulation signal using the input / output characteristics of the amplifier.

  The distortion compensation signal generation / addition unit 2 shown in FIG. 2 performs non-linear information (for example, AM-AM characteristics, AM which are input / output characteristics of the amplifier 5), which has been acquired by performing measurement or the like in advance. -Non-linear processing based on PM characteristics, etc.) is performed on the input signal to generate a modulation signal that has a distortion component when passing through the amplifier and whose peak power is suppressed according to the nonlinear characteristics of the amplifier A subtractor 22 that extracts a distortion component when passing through the amplifier 5 by subtracting the original modulation signal from the output of the processing unit 21, the nonlinear processing unit 21, and a distortion component in the band from the output of the subtraction unit 22. A filter unit 23 for extraction, a subtraction unit 24 for subtracting the output of the filter unit 23 from the output of the subtraction unit 22, and an original modulation signal (input signal to the distortion compensation signal generation / addition unit 2). Subtracting section 25 for generating a modulation signal to which a signal (distortion compensation signal) for attenuating an out-of-band distortion component at the time of passing through the amplifier is subtracted by subtracting the output of subtracting section 24 from Yes. The non-linear processing unit 21, the subtracting unit 22, the filter unit 23, and the subtracting unit 24 constitute a distortion component generating unit, and the subtracting unit 25 constitutes a distortion component subtracting unit.

  FIGS. 4-1 to 4-6 are diagrams for explaining the operation of the distortion compensation signal generation / addition unit 2 of the present embodiment, and show the spectrum characteristics of the signals S1 to S6 shown in FIG. Yes. FIG. 4A shows, as an example, spectrum characteristics of the signal S1 input to the distortion compensation signal generation / addition unit 2 when the modulation is multicarrier modulation. FIG. 4B is a spectrum characteristic of the signal S <b> 2 output from the nonlinear processing unit 21. FIG. 4C is a spectrum characteristic of the signal S3 output from the subtracting unit 22. FIG. 4-4 is a spectrum characteristic of the signal S4 output from the filter unit 23. FIG. 4-5 is a spectrum characteristic of the signal S5 output from the subtracting unit 24. 4-6 shows the spectrum characteristics of the signal S6 output from the subtractor 25. FIG.

  Hereinafter, the operation of the distortion compensation signal generation / addition unit 2 that performs the characteristic operation of the transmission apparatus according to the present invention will be described with reference to FIGS. 2 and 4-1 to 4-6. The modulation signal output from the modulation unit 1 is input to the distortion compensation signal generation / addition unit 2 as a signal S1. Here, description will be made assuming that OFDM, which is multicarrier modulation, is used as a modulation signal having a large peak power.

  In the distortion compensation signal generation / addition unit 2, the nonlinear processing unit 21 corresponding to the nonlinear processing execution unit includes nonlinear information (AM-AM characteristics, such as an amplifier / analog device shown in FIGS. 3A and 3B). AM-PM characteristics, etc.) and non-linear processing is performed on the input signal S1 (spectrum characteristics are shown in FIG. 4A) based on signal input level information regarding the operating point of the amplifier. Note that the nonlinear processing executed here is the same processing as the signal amplification processing executed in the amplifier 5, for example. By this non-linear processing, a peak-suppressed signal S2 is generated. The spectrum characteristic of the output signal S2 of the non-linear processing unit 2 is a spectrum in which out-of-band radiation occurs as shown in FIG.

  Here, the input / output characteristics of the amplifier 5 are processed as non-linear information, but the D / A conversion unit 3, the frequency conversion unit 4 and the amplifier 5 located at the subsequent stage of the distortion compensation signal generation / addition unit 2 are combined into one. It may be regarded as a device, and the input / output characteristics for this device may be processed as nonlinear information.

  Next, the output signal S2 of the nonlinear processing unit 21 and the original signal S1 are input to the subtractor 22. The subtractor 22 subtracts the signal S1 from the signal S2, thereby extracting a distortion component generated when passing through the nonlinear processing unit 21. The spectrum characteristic of the output signal S3 of the subtractor 22 is a spectrum of distortion components generated in and out of the band by nonlinear processing based on the nonlinear information as shown in FIG. 4-3. In other words, the peak power of the modulation signal is suppressed by distorting the modulation signal (signal S1) based on nonlinear characteristics such as an amplifier. In general, in wireless communication, it is necessary to suppress out-of-band radiation to a level defined by a standard or the like so as not to cause interference with adjacent channels. On the other hand, the distortion in the band is defined by the modulation accuracy, but the conditions are not stricter than the regulations regarding out-of-band radiation. Therefore, in the present invention, in order to suppress the peak power of the modulation signal, the distortion component outside the band is suppressed by leaving the distortion component within the band. A method for extracting only out-of-band distortion components necessary for realizing this and a method for generating a distortion compensation signal using the extracted out-of-band distortion components will be described below.

  The output signal S3 of the subtracter 22 is input to the filter unit 23 and the subtracter 24. The filter unit 23 extracts a distortion component signal in the band of the original modulation signal S1 from the input signal S3. Therefore, in the filter unit 23, as shown by the solid line in FIG. 4-4, the spectrum of the original modulation signal (see FIG. 4-1) and the spectrum of the distortion component signal (see FIG. 4-3) almost overlap each other. The band limiting process is performed by a filter having a spectrum shape corresponding to. As a means for realizing the filter unit 23 having such a spectrum of conditions, an FIR filter can be considered.

  The output signal S4 of the filter unit 23 is input to the subtracter 24 together with the output signal S3 of the subtractor 22. The subtractor 24 subtracts the signal S4 from the signal S3, thereby extracting the signal S5, which is an out-of-band component of the modulation signal, having a spectrum shape as shown in FIG. 4-5.

  The output signal S5 of the subtracter 24 is input to the subtracter 25 together with the original modulation signal S1. The subtracter 25 subtracts S5 from the signal S1, thereby extracting a modulation signal S6 having a spectrum shape as shown in FIG. Although the spectrum of the signal S6 shown in FIG. 4-6 and the spectrum of the signal S2 shown in FIG. 4-2 have the same shape in terms of power, the signal corresponding to the out-of-band distortion component is positive and negative. The negative sign is inverted, and the signal compensates for out-of-band distortion with respect to the original modulation signal generated when passing through the amplifier.

  The output signal S6 of the distortion compensation signal generation / addition unit 2 is input to the D / A conversion unit 3, converted into an analog signal, and then input to the frequency conversion unit 4. The frequency conversion unit 4 performs frequency conversion of the output of the D / A conversion unit 3 up to the RF band, and the frequency-converted signal is input to the amplifier 5. The amplifier 5 amplifies the output signal of the frequency converter 4, but the amplifier 5 itself has a non-linear characteristic as shown in FIG. FIGS. 5A and 5B illustrate the spectrum characteristics of the signal before passing through the amplifier 5 and the spectrum characteristics of the signal after passing through the amplifier 5, respectively. The spectrum of the signal before passing through the amplifier 5 (FIG. 5-1) is obtained by adding the spectrum of the signal that compensates for the distortion outside the band described above to the spectrum of the original modulation signal. In the signal before passing through the amplifier 5, the distortion component in the band is suppressed by the filter unit 23. Therefore, after passing through the amplifier 5, the distortion as shown in FIG. 4-3 occurs, but the distortion component outside the band is reduced by the distortion compensation signal (signal for compensating the distortion outside the band). As shown in -2, the out-of-band component is sufficiently reduced.

  As described above, in the present embodiment, the distortion compensation signal generation / addition unit uses the nonlinear characteristic of the amplifier to suppress the peak power of the modulation signal. In other words, by performing nonlinear processing simulated by the amplifier on the modulated signal in advance, a type of peak-suppressed signal is generated, and this signal can be used to reduce out-of-band distortion caused by amplification processing in the amplifier A modulation signal to which a distortion compensation signal is added is generated. Then, the modulated signal to which the distortion compensation signal is added is amplified and transmitted. As a result, it is possible to obtain a transmission device that can reduce out-of-band radiation while suppressing deterioration in modulation accuracy of the modulation signal as much as possible and suppressing peak power according to the characteristics of the amplifier.

Embodiment 2. FIG.
Next, the second embodiment will be described. In the first embodiment, the operation of the transmission apparatus that suppresses peak power using nonlinear information (AM-AM characteristics, AM-PM characteristics, etc.) acquired by performing measurement or the like in advance has been described. In this embodiment, the operation of the transmission apparatus that updates nonlinear information as necessary and suppresses peak power using the updated nonlinear information will be described.

  FIG. 6 is a diagram illustrating a configuration example of the transmission apparatus according to the second embodiment. The transmission apparatus according to the present embodiment has a delay device 11, a nonlinear information generation unit 12, an A / D conversion unit 13, a frequency conversion unit 14, and an attenuator 15 added to the transmission device according to the first embodiment described above. It becomes the composition. Since the other parts are the same as those of the transmission apparatus of the first embodiment, the same reference numerals are given and description thereof is omitted. The configuration of the distortion compensation signal generation / addition unit is the same as that of the distortion compensation signal generation / addition unit 2 of the first embodiment. As described above, the operation of the distortion compensation signal generation / addition unit is the same as that of the distortion compensation signal generation / addition unit of Embodiment 1 except that the nonlinear information to be used varies (updates) with time. . For this reason, in the present embodiment, description will be made centering on the operation in which the transmission apparatus updates the nonlinear information. The delay unit 11, the nonlinear information generation unit 12, the A / D conversion unit 13, the frequency conversion unit 14, and the attenuator 15 constitute nonlinear information generation and output means.

  The nonlinear information generation unit 12 included in the transmission device of the present embodiment compares the input signal to the D / A conversion unit 3 and the output signal of the A / D conversion unit 13, thereby obtaining nonlinear information (AM-AM characteristics, AM-PM characteristics, etc.) are updated over time. Hereinafter, the update operation of nonlinear information will be described.

  The transmission signal (the output of the amplifier 5) generated by executing the operation described in the first embodiment is branched and input to the attenuator 15. The attenuator 15 attenuates the signal output of the amplifier 5 to an appropriate level (for example, the level before being amplified by the amplifier 5), and then outputs the attenuated signal to the frequency converter 14. The frequency conversion unit 14 converts the RF band modulation signal output from the attenuator 15 into a baseband signal, and then outputs the signal to the A / D conversion unit 13. The A / D converter 13 converts the baseband analog signal output from the frequency converter 14 into a digital signal. The attenuator 15, the frequency conversion unit 14, and the A / D conversion unit 13 constitute a virtual output signal generation unit.

  The output of the A / D conversion unit 13 is input to the nonlinear information generation unit 12. The output of the distortion compensation signal generation / addition unit 2 is also input to the nonlinear information generation unit 12 through the delay unit 11. However, the delay amount of the delay device 11 is set so that the output signal of the distortion compensation signal generation / addition unit 2 input to the nonlinear information generation unit 12 and the output signal of the A / D conversion unit 13 have the same timing. . The nonlinear information generation unit 12 generates nonlinear information based on the signal input from the A / D conversion unit 13 and the signal input from the distortion compensation signal generation adding unit 2 via the delay unit 11. Specifically, an input / output characteristic (AM-AM characteristic, AM) in which the output signal of the distortion-compensated signal generation / addition unit 2 subjected to delay adjustment is “input” and the output signal of the A / D conversion unit 13 is “output”. -PM characteristics, etc.). Note that the signal power is controlled by automatic gain control (AGC) or the like so that the two signal levels input to the nonlinear information generation unit are equal in average power as a condition for generating input / output characteristics. It shall be.

A method for generating the nonlinear information (input / output characteristics) will be described in detail. When the output signal (input and complex signal) of the delay unit 11 is “x (k)” and the output signal (output and complex signal) of the A / D converter 13 is “y (k)”, The relationship between input and output is expressed by the following equation (2). However, “k” represents the sample time.
y (k) = W (k) .x (k) (2)
Here, “W (k)” is a complex weight indicating the influence of input / output characteristics (AM-AM characteristics, AM-PM characteristics, etc.) related to nonlinearity caused by an amplifier / analog device, etc. Indicated by
W (k) = (y (k) · x (k) * ) / | x (k) | 2 = R (k) · exp (jΔθ (k)) (3)
However, “R (k)” is an amplitude, and “Δθ (k)” is a phase. '*' Indicates a complex conjugate. Here, “R (k)” and “Δθ (k)” mainly depend on the signal amplitude level (| x (k) |) input to the amplifier, as shown in the above equation (3).

  By the way, when calculating the complex weight (W (k)), in an actual amplifier / analog system, the AM-AM characteristic and AM-PM characteristic fluctuate due to the influence of temperature change, thermal noise, and the like. Therefore, the nonlinear information generation unit 12 needs to perform an averaging process while following the characteristic variation according to the signal amplitude level (| x (k) |). In order to realize this, first, the output signal of the distortion-compensated signal generation / addition unit 2 subjected to the delay adjustment is defined as an “input side signal”, and the output signal of the A / D conversion unit 13 is defined as an “output side signal”. Further, in order to obtain highly accurate input / output characteristics, as shown in FIG. 7, the input level range is divided into N fine blocks corresponding to the amplitude level of the input side signal. FIG. 7 is a diagram showing a state in which the signal input level (| x (k) |) is divided into N blocks. When the amplitude (| x (k) |) of the input side signal sample at a certain time k is an input level corresponding to, for example, “(N−3) · Δ”, “(N−3) · Δ The input / output characteristics are generated by performing only the averaging processing of the block corresponding to “,” and a complex weight indicating the influence of the generated input / output characteristics (AM-AM characteristics, AM-PM characteristics) is generated. The complex weight (Wm) at this time is expressed by the following equation (4).

Wm = (1−α) · Wm + α · {(y (k) · x (k) * ) / | x (k) | 2 } (4)
Here, 0 ≦ m ≦ N, and m = N−3 in the block corresponding to “(N−3) · Δ” in the above description. Further, α <1. Further, the processing of (1 / | x (k) | 2 ) in the above equation (4) is performed in advance for N blocks of data Zm (0 ≦ m ≦ N), for example, in a table format for the corresponding block m. By preparing in step 1, it is not necessary to perform division processing. Therefore, the equation (4) can be expressed by the following equation (5).
Wm = (1−α) · Wm + α · {(y (k) · x (k) * ) · Zm} (5)
However, m · Δ ≦ | x (k) | <(m + 1) · Δ.

The nonlinear information generation unit 12 outputs Wm (0 ≦ m ≦ N) obtained by the above equation (5) to the distortion compensation signal generation / addition unit 2 as nonlinear information such as an amplifier / analog device. The nonlinear processing unit 21 of the distortion compensation signal generation / addition unit 2 shown in FIG. 1 selects Wm corresponding to a range of m · Δ ≦ | x (k) | <(m + 1) · Δ of the inputted nonlinear information. Thus, nonlinear processing is performed by multiplying x (k). Assuming that the nonlinear processing result is “C (k)” (where k is a sample number and a complex signal), “C (k)” is expressed by the following equation (6).
C (k) = Wm · x (k), 0 ≦ m ≦ N (6)

  As described above, in the transmission apparatus according to the present embodiment, the nonlinear information generator updates nonlinear information in response to changes in nonlinear characteristics of amplifiers / analog devices, etc. due to temperature changes, and distortion compensation is performed on the updated nonlinear information. The signal is output to the signal generation / addition unit. Accordingly, peak power suppression and distortion compensation can be performed using optimal nonlinear information that follows time fluctuations of nonlinear characteristics of an amplifier / analog device or the like.

  As described above, the transmission apparatus according to the present invention is useful for wireless communication, and in particular, compensates for distortion while suppressing the occurrence of out-of-band radiation in the peak level suppression processing of a transmission signal that is nonlinear amplitude limitation. It is suitable for a transmitter capable of

It is a figure which shows the structural example of Embodiment 1 of the transmitter concerning this invention. It is a figure which shows the structural example of a distortion compensation signal production | generation addition part. It is the figure which showed the input-output characteristic (AM-AM characteristic) example of the amplifier with which the transmitter was equipped. It is the figure which showed the input-output characteristic (AM-PM characteristic) example of the amplifier with which the transmitter was equipped. It is a figure which shows the example of a spectrum characteristic of signal S1. It is a figure which shows the example of a spectrum characteristic of signal S2. It is a figure which shows the example of a spectrum characteristic of signal S3. It is a figure which shows the example of a spectrum characteristic of signal S4. It is a figure which shows the example of a spectrum characteristic of signal S5. It is a figure which shows the example of a spectrum characteristic of signal S6. It is a figure which shows the spectrum characteristic example of the signal before amplifier passage. It is a figure which shows the example of the spectrum characteristic of the signal after amplifier passing. It is a figure which shows the structural example of Embodiment 2 of the transmitter concerning this invention. It is a figure for demonstrating the nonlinear information generation operation | movement in a nonlinear information generation part. It is the figure which showed the basic composition of the transmitter which can reduce the peak electric power of the modulation signal of the conventional multicarrier modulation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Modulation part 2 Distortion compensation signal production | generation addition part 3 D / A conversion part 4, 14, 94 Frequency conversion part 5, 95 Amplifier 6, 96 Antenna 11 Delay device 12 Nonlinear information generation part 13 A / D conversion part 15 Attenuator 21 Non-linear processing unit 22, 24, 25 Subtraction unit 23, 93 Filter unit 91 Modulator 92 Clip unit

Claims (7)

  1. A transmission apparatus comprising transmission signal generation means for executing a predetermined transmission signal generation process on a baseband digital modulation signal,
    The transmission signal generation means generates a transmission signal for the input signal based on a baseband digital modulation signal as an input signal and non-linear information indicating the input / output characteristics of the transmission signal generation means acquired in advance. A distortion component generation means for generating an out-of-band distortion component generated when the processing is executed;
    Distortion component subtracting means for subtracting out-of-band distortion components generated by the distortion component generating means from the baseband digital modulation signal input to the distortion component generating means;
    With
    The transmission apparatus, wherein the transmission signal generation means performs the transmission signal generation process on a baseband digital modulation signal after the distortion component subtraction.
  2.   2. The transmission apparatus according to claim 1, wherein the distortion component generation unit generates a distortion component outside a band including a distortion component generated in accordance with signal amplification processing.
  3. The distortion component generation means includes
    Nonlinear processing execution means for executing nonlinear processing similar to the transmission signal generation processing executed by the transmission signal generation means on the input signal based on the nonlinear information;
    First subtraction means for extracting a distortion component generated by the nonlinear processing by subtracting the input signal from the output signal of the nonlinear processing execution means;
    Filter means for extracting a distortion component in the same band as the input signal from the output signal of the first subtracting means;
    Second subtraction means for extracting out-of-band distortion components by subtracting the output of the filter means from the output signal of the first subtraction means;
    The transmission device according to claim 1, further comprising:
  4. further,
    Based on the output signal of the distortion component subtracting means and the transmission signal obtained by the transmission signal generating means performing transmission signal generation processing on the output signal, the input / output characteristics of the transmission signal generating means are obtained. Non-linear information generating / outputting means for generating and outputting non-linear information indicating;
    With
    The distortion component generation means generates out-of-band distortion components using nonlinear information output from the nonlinear information generation / output means instead of the previously acquired nonlinear information. The transmission apparatus according to 1, 2, or 3.
  5. The nonlinear information generation / output means includes
    A delay unit that generates a virtual input signal to be used when generating nonlinear information by delaying an output signal of the distortion component subtracting unit;
    A hypothesis used when generating nonlinear information by executing a process opposite to the transmission signal generation process performed when generating the transmission signal for the transmission signal that is an output signal of the transmission signal generating unit. Virtual output signal generating means for generating an output signal;
    Non-linear information generating means for generating input / output characteristics of the virtual input signal and the virtual output signal and outputting the generated input / output characteristics as non-linear information;
    The transmission apparatus according to claim 4, further comprising:
  6.   The delay means gives a delay so that the output signal of the distortion component subtracting means is input to the nonlinear information generating means at the same timing as the output signal of the virtual output signal generating means corresponding to the output signal. The transmission device according to claim 5, characterized in that:
  7.   The non-linear information generating means divides the input level range of the virtual input signal from the delay unit into a plurality of blocks with a constant interval, and when the virtual input signal is input, the amplitude level of the virtual input signal is 7. The transmission apparatus according to claim 5, wherein which block corresponds is determined, and nonlinear information is generated for each block corresponding to the signal amplitude level.
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