Nonlinear distortion compensating circuit

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a non-linear distortion compensating circuit that compensates for non-linear distortion generated by the non-linear characteristics of input / output characteristics in a compensated high frequency amplifier circuit.

【0002】

[Conventional technology]

As a non-linear distortion compensation circuit of this kind, a non-linear distortion compensation circuit based on a predistortion method disclosed in Japanese Patent Publication No. 7-101820 and Japanese Patent Publication No. 8-15245 has been conventionally known. FIG. 6 shows the basic configuration of the high-frequency power amplifier 61 provided with the nonlinear distortion compensation circuit by this predistortion method. As shown in the figure, the high-frequency power amplifier 61 includes a nonlinear strain compensation circuit 41 and a high-frequency amplifier circuit 51 as a compensated high-frequency amplifier circuit. In this case, the nonlinear distortion compensation circuit 41 is connected to the previous stage of the high-frequency amplifier circuit 51, and the distortion signal ε for removing the third-order intermodulation distortion generated when the high-frequency signal Si is amplified by the high-frequency amplifier circuit 51. Is added to the high-frequency signal Si in advance to reduce the high-order intermodulation distortion of the output signal So output from the high-frequency amplifier circuit 51.

【0003】

In this high-frequency power amplifier 61, in principle, when the nonlinear distortion compensation circuit 41 inputs a high-frequency signal Si whose signal component and its voltage are represented by "Si", the signal component and its voltage become a voltage "Si". A distortion signal ε represented by ε is generated inside the strain signal ε, and a drive signal Sd whose signal component and its voltage are represented by (Si + ε) is output. Next, the high-frequency amplifier circuit 51 amplifies the drive signal Sd with a predetermined gain G. In this case, when the signal component of the distorted signal δ generated inside the high-frequency amplifier circuit 51 and its voltage are represented by δ, the high-frequency amplifier circuit 51 has the signal component and its voltage (G · (Si + ε. ) + δ) is output as the output signal So. Therefore, when the signal component of the distortion signal ε generated by the non-linear distortion compensation circuit 41 and its voltage are represented by (δ / G), that is, ε and δ are out of phase and When the absolute value of the voltage satisfies the relational expression (ε = δ / G) (hereinafter, also simply referred to as compensation condition), the high-frequency amplifier circuit 51 has a signal component and a voltage of G · Si. The represented output signal So is output. Therefore, when the above compensation conditions are satisfied for all high-frequency signals Si, the nonlinear distortion component of the output signal So output by the high-frequency amplifier circuit 51 is compensated and suppressed.

【0004】

Specifically, as shown in FIG. 7, the nonlinear distortion compensation circuit 41 includes a power distributor 42, a distortion generating circuit 43, a linear circuit 44,45, and a power synthesizer 46,47. In the nonlinear distortion compensation circuit 41, the power distributor 42 distributes the high frequency signal Si into three and outputs the high frequency signal Si to the distortion generation circuit 43, the linear circuit 44, and the linear circuit 45. Next, the distortion generation circuit 43 amplifies the distributed high-frequency signal Si with a predetermined gain, generates a distortion signal ε, and outputs it as a signal S11. In this case, the signal component and voltage of the signal S11 shall be represented by "(Si + ε)". At the same time, the linear circuit 44 linearly amplifies the distributed high frequency signal Si with a predetermined gain and outputs it as the signal S12. In this case, the signal component and voltage of the signal S12 are represented by "Si". The power synthesizer 46 then subtracts the signal S11 from the signal S12. As a result, the high-frequency signal Si is canceled out, and the power synthesizer 46 outputs the distorted signal ε of the opposite phase as the signal S13. On the other hand, the linear circuit 45 also linearly amplifies the distributed high frequency signal Si with a predetermined gain and outputs it as the signal S14. In this case, the signal component and voltage of the signal S14 shall be represented by "Si". Next, the power synthesizer 47 adds the signal S13 and the signal S14 to generate a drive signal Sd whose signal component and voltage are represented by "(Si + ε)". Therefore, when the voltage level (amplitude) of the high-frequency signal Si, the frequency of the high-frequency signal Si, the temperature, etc. are used as parameters, as long as the non-linear distortion compensation circuit 41 outputs the above drive signal Sd regardless of the fluctuation of these parameters, The high-order intermodulation distortion of the output signal So output by the high-frequency amplifier circuit 51 is compensated and suppressed.

【0005】

[Problems to be Solved by the Invention]

However, this nonlinear distortion compensation circuit 41 has the following problems. That is, in today's wide-band transmission signal, there is a demand for further suppression of higher-order intermodulation distortion contained in the output signal So transmitted by the high-frequency amplifier circuit 51. On the other hand, in the conventional nonlinear distortion compensation circuit 41, a distortion signal ε is added to the high frequency signal Si in order to suppress the third-order intermodulation distortion generated in the high frequency amplifier circuit 51. Therefore, in the high-frequency power amplification device 61 using the conventional nonlinear distortion compensation circuit 41, even if the third-order intermodulation distortion can be suppressed, higher-order intermodulation such as fifth-order intermodulation distortion and seventh-order intermodulation distortion can be suppressed. At present, the modulation distortion cannot be removed. Therefore, conventionally, in order to suppress higher-order intermodulation distortion, a large amount of current is supplied to linearly amplify the power amplifier provided inside the high-frequency amplifier circuit 51, or by cut and try. It adjusts the bias and matching of the power amplifier. However, even if these methods are used, for example, although the 5th-order intermodulation distortion can be suppressed, the 7th-order intermodulation distortion can be increased or the 7th-order intermodulation distortion can be suppressed. However, it is very difficult to uniformly suppress all higher-order intermodulation distortions, such as an increase in fifth-order intermodulation distortion. In addition, when these methods are adopted, there are problems such as a decrease in efficiency due to an increase in current consumption and an increase in equipment cost due to an increase in adjustment cost.

【0006】

The present invention has been made in view of the above problems, and an object of the present invention is to provide a non-linear distortion compensating circuit capable of sufficiently suppressing the non-linear distortion of the compensated high frequency amplifier circuit while maintaining high efficiency.

【0007】

[Means for solving problems]

The non-linear strain compensation circuit according to the present invention in order to achieve the above object is a non-linear distortion compensation circuit for compensating the non-linear distortion of the compensated high frequency amplifier circuit, and the Nth-order intermodulation distortion (N is) as the non-linear distortion. An Nth-order distortion signal capable of compensating for each of the natural number 3 and any one or any plurality of odds of 5 or more is generated based on the input high-frequency signal, and the generated Nth-order distortion is generated. The signal and the input high frequency signal are combined and output as an output signal.

【0008】

In this case, a plurality of distortion generation circuits that generate each Nth-order distortion signal based on the input high-frequency signal, a linear circuit that linearly amplifies the input high-frequency signal, each of the generated Nth-order distortion signals, and the above. It is preferable to include an output synthesis circuit that synthesizes a linearly amplified input high frequency signal to generate the output signal.

【0009】

Further, a linear circuit that linearly amplifies the input high-frequency signal, a third-order distortion generation circuit that inputs the input high-frequency signal to generate a third-order distortion signal, and a third-order distortion signal and 5 that input the input high-frequency signal. A fifth-order distortion generation circuit that generates a next-order distortion signal and an output synthesis circuit that generates the output signal are provided, and the output synthesis circuit includes a first distributor that distributes the output signal of the third-order distortion generation circuit. The fifth-order distortion signal is obtained by subtracting the distribution signal distributed by the first distributor from the second distributor that distributes the output signal of the fifth-order distortion generation circuit and the distribution signal distributed by the second distributor. The first synthesizer to be generated, the third-order distortion signal distributed by the first distributor, the fifth-order distortion signal generated by the first synthesizer, and the linearly amplified input high-frequency signal are combined. It is preferable that the device is provided with a second synthesizer that outputs the output signal.

【0010】

Further, a vector amount adjusting circuit for third-order distortion configured so that the vector amount of the output signal output by the third-order distortion generation circuit can be adjusted, and a vector of the output signal output by the fifth-order distortion generation circuit. It is preferable to have a vector amount adjusting circuit for fifth-order distortion configured so that the amount can be adjusted.

【0011】

Further, a first vector quantity adjustment circuit configured to be able to adjust the vector amount of the third-order distortion signal distributed by the first distributor, and a vector of the fifth-order distortion signal generated by the first synthesizer. It is preferable to have a second vector quantity adjusting circuit configured so that the quantity can be adjusted.

【0012】

Further, a detector that detects at least one of the frequency of the input high frequency signal, the power of the input high frequency signal, the temperature inside or near the nonlinear distortion compensating circuit, and the temperature inside or near the compensated high frequency amplifier circuit. And the memory that stores each adjustment amount of the 3rd-order distortion vector amount adjustment circuit and the 5th-order distortion vector amount adjustment circuit corresponding to the detection signal detected by the detector, and the input detection signal. Each of the corresponding adjustment amounts is read from the memory, and the third-order distortion vector amount adjustment circuit and the control circuit for controlling the fifth-order distortion vector amount adjustment circuit by the corresponding read-out adjustment amounts are provided. Is preferable.

【0013】

Further, a control circuit that controls the adjustment amount of the first vector amount adjustment circuit and the adjustment amount of the second vector amount adjustment circuit so that the non-linear distortion included in the output signal of the compensated high frequency amplifier circuit is reduced. It is preferable to have it.

【0014】

Further, it is preferable that each of the vector quantity adjusting circuits is configured so that the attenuation amount and the phase amount of the corresponding distortion signal can be adjusted.

【0015】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the nonlinear strain compensation circuit according to the present invention will be described with reference to the accompanying drawings. Since the high-frequency amplifier circuit connected to the subsequent stage of the nonlinear distortion compensation circuit according to the present invention has the same configuration as the conventional high-frequency amplifier circuit 51, duplicate description will be omitted. Further, the same components and signals described above are designated by the same reference numerals, and duplicate description will be omitted.

【0016】

First, the basic configuration of the nonlinear distortion compensation circuit 1 will be described with reference to the block diagram shown in FIG. This nonlinear distortion compensation circuit 1 predistorts the nonlinear distortion from the third-order intermodulation distortion to the Nth-order intermodulation distortion generated during power amplification by the high-frequency amplifier circuit 51 (not shown) as the compensated high-frequency amplifier circuit. The Nth-order distortion signal εN (N is an odd number of 3 or more and a predetermined number or less, hereinafter also referred to as distortion signal ε when not distinguished) is a high frequency signal Si (input high frequency signal in the present invention) that can be compensated by the method. It is configured to be generateable based on. Specifically, the nonlinear distortion compensation circuit 1 distributes the high-frequency signal Si to the distribution signals S1-1, S1-3, ... S1-N (hereinafter, also referred to as "distribution signal S1" when not distinguished). It is equipped with an input distributor 2. Further, the non-linear distortion compensation circuit 1 is a third-order distortion generation circuit 3-3 that generates a third-order distortion signal ε3 (hereinafter, also referred to as a distortion generation circuit 3 when not distinguishing including each distortion generation circuit described later). And, the vector amount adjustment circuit for third-order distortion that adjusts the vector amount of the third-order distortion signal ε3 4-3 (hereinafter, when not distinguishing including each vector amount adjustment circuit for distortion described later, "vector amount adjustment circuit 4" Also known as). Hereinafter, the pair of M-th order (M is an odd number of 3 or more and N or less) distortion generation circuit 3 and the M-th order distortion vector amount adjustment circuit 4 are collectively referred to simply as "M-th order distortion generation series". Further, the nonlinear distortion compensation circuit 1 has a distortion generation sequence from the 5th order to the Nth order.

【0017】

Further, the non-linear distortion compensation circuit 1 includes a linear circuit 5 that linearly amplifies the distribution signal S1-1 to, for example, the power level of the high-frequency signal Si, and a third-order distortion signal ε3 to Nth-order distortion output from each vector amount adjustment circuit 4. It includes an output synthesis circuit 6 that synthesizes the signal εN and the high frequency signal Si output from the linear circuit 5 and outputs the drive signal Sd corresponding to the output signal in the present invention.

【0018】

Next, the operating principle of the nonlinear distortion compensation circuit 1 will be described.

【0019】

In this nonlinear distortion compensation circuit 1, the input distributor 2 distributes the high-frequency signal Si and outputs the distribution signals S1-1 to S1-N to the linear circuit 5 and the distortion generation circuits 3-3 to 3-N. Next, the 3rd-order distortion generation circuit 3-3 generates a 3rd-order distortion signal ε3 for compensating for the 3rd-order intermodulation distortion, and the 5th-order distortion generation circuit 3-5 for compensating for the 5th-order intermodulation distortion. The fifth-order distortion signal ε5 is generated, and similarly, the higher-order distortion signal ε for compensating the corresponding higher-order intermodulation distortion by the other distortion generation circuits 3 up to the Nth order is generated. As a result, the third-order distortion signals ε3 to Nth-order distortion signals εN for compensating for the higher-order intermodulation distortion from the third order to the Nth order are generated. On the other hand, the linear circuit 5 linearly amplifies the distribution signal S1-1 to a voltage level equal to, for example, the high frequency signal Si. Next, as shown in FIG. 2, the output synthesis circuit 6 outputs the drive signal Sd synthesized by the high-frequency signal Si and the distortion signal ε from the third-order distortion signal ε3 to the Nth-order distortion signal εN. In this case, in the figure, the voltage phases of the third-order distortion signals ε3 to Nth-order distortion signals εN are inverted with the voltage phases of the higher-order intermodulation distortion generated due to the amplification by the high-frequency amplifier circuit 51 described later. The signal component of the high-frequency signal Si is represented in the positive direction, and the signal components of the third-order distortion signal ε3 to Nth-order distortion signal εN are represented in the negative direction so that can be easily understood.

【0020】

Next, the high-frequency amplifier circuit 51 inputs the drive signal Sd and amplifies the power with the gain G. At this time, assuming that the drive signal Sd does not include the third-order distortion signal ε3 to Nth-order distortion signal εN, the high-frequency amplifier circuit 51 has a signal component (G · Sd + δ) as shown in FIG. ) Is generated as an output signal So. In this case, the distortion signal δ means a composite signal of the third-order distortion signal ε3', the fifth-order distortion signal ε5', ..., And the Nth-order distortion signal εN'shown in the figure. Therefore, each voltage level of the third-order distortion signal ε3, the fifth-order distortion signal ε5, the seventh-order distortion signal ε7, ..., The Nth-order distortion signal εN so as to satisfy the above compensation condition (ε = δ / G). The voltage level obtained by multiplying each by the gain G, and the third-order distortion signal ε3', fifth-order distortion signal ε5', seventh-order distortion signal ε7', ..., Nth-order distortion signal εN'generated by the high-frequency amplification circuit 51. When the voltage levels are equal to each other and the phases are inverted, the third-order distortion signal ε3 compensates and suppresses the third-order distortion signal ε3', and similarly, the fifth-order distortion signal ε5 compensates for and suppresses the fifth-order distortion signal. ε5'is compensated and suppressed, the 7th distortion signal ε7 is compensated and suppressed by the 7th distortion signal ε7, ..., The Nth distortion signal εN' is compensated and suppressed by the Nth distortion signal εN. To. As a result, when the drive signal Sd output from the nonlinear distortion compensation circuit 1 is input to the high-frequency amplifier circuit 51, theoretically, each higher-order intermodulation distortion is suppressed as shown in FIG. The high-frequency amplifier circuit 51 outputs an output signal So composed of only the signal components of the high-frequency signal Si.

【0021】

As described above, according to this non-linear distortion compensation circuit 1, efficiency is reduced by synthesizing the distortion signal ε from the third-order distortion signal ε3 to the Nth-order distortion signal εN and the high-frequency signal Si by the predistortion method. The high-order intermodulation distortion generated when the high-frequency amplifier circuit 51 amplifies the high-frequency signal Si can be uniformly and sufficiently suppressed without causing an increase in the device cost due to the adjustment cost.

【0022】

Next, referring to FIG. 5, the third-order distortion signal ε3 for suppressing the third-order intermodulation distortion, the fifth-order intermodulation distortion, and the seventh-order intermodulation distortion as the high-order intermodulation distortion generated in the high-frequency amplifier circuit 51. , A specific configuration example of the nonlinear distortion compensation circuit 1 that synthesizes the 5th-order distortion signal ε5 and the 7th-order distortion signal ε7 with the high-frequency signal Si will be described. The same components as those described above are designated by the same reference numerals, and duplicate description will be omitted.

【0023】

As shown in the figure, the nonlinear distortion compensation circuit 1 generates an input distributor 2 composed of a transformer or the like, a third-order distortion generation circuit 3-3 that generates a third-order distortion signal ε3, and a fifth-order distortion signal ε5. 5th-order distortion generation circuit 3-5, 7th-order distortion generation circuit that generates 7th-order distortion signal ε7, 7th-order distortion generation circuit 3-7, 3rd-order distortion vector amount adjustment circuit for adjusting the vector amount of 3rd-order distortion signal ε3 4- 5th-order distortion vector amount adjustment circuit for adjusting the vector amount of the 3rd and 5th-order distortion signal ε5 4-5, 7th-order distortion vector amount adjustment circuit for adjusting the vector amount of the 7th-order distortion signal ε7 4- 7, Output synthesis circuit 6, P / F detector (detector) 11 that detects the power value and frequency of the high-frequency signal Si, for example, a temperature sensor (detector) 12 that detects the internal temperature of the nonlinear distortion compensation circuit 1, CPU It is configured with 13 (control circuit), 14 ROM (memory) and 15 distortion detector. The temperature sensor 12 can be configured to be capable of detecting at least one of the temperature inside or near the nonlinear amplifier circuit 1 and the temperature inside or near the high frequency amplifier circuit 51.

【0024】

The 3rd-order distortion generation circuit 3-3, the 5th-order distortion generation circuit 3-5, and the 7th-order distortion generation circuit 3-7 are configured in the same manner, and have a distributor 21, a variable amplifier 22, a variable attenuator 23, an amplifier 24, and a variable. It is configured to include a phase device 25 and a synthesizer 26. In this case, the distributor 21 divides the distribution signal S1 into two and outputs the distribution signal S1 to the variable amplifier 22 and the amplifier 24. The variable amplifier 22 uses the gain control signal SG3 (or SG5, SG7, hereinafter, when not distinguished, the gain control signal SG, which is output from the CPU 13). The distribution signal S1 is amplified with a gain according to (also called). Further, the variable amplifier 22 of the third-order distortion generation circuit 3-3 non-linearly amplifies the distribution signal S1 with a gain larger than the gain of the amplifier 24, and outputs the third-order distortion signal ε3 together with the amplified high-frequency signal Si. On the other hand, the variable amplifier 22 of the fifth-order distortion generation circuit 3-5 non-linearly amplifies the distribution signal S1 with a gain larger than the gain of the amplifier 24, and together with the amplified high-frequency signal Si, the third-order distortion signal ε3 and the fifth-order distortion signal. Outputs ε5. Further, the variable amplifier 22 of the 7th-order distortion generation circuit 3-7 non-linearly amplifies the distribution signal S1 with a gain larger than the gain of the amplifier 24, and together with the amplified high-frequency signal Si, the 3rd-order distortion signal ε3 and the 5th-order distortion signal. Outputs ε5 and 7th-order distortion signal ε7. The variable attenuator 23 uses the attenuation control signal SA3 (or SA5, SA7, hereinafter, the attenuation control signal SA) output from the CPU 13 when no distinction is made. The distribution signal S1 amplified by the variable amplifier 22 is attenuated by an amount of attenuation corresponding to (also referred to as), and a high-frequency signal Si having the same power as the high-frequency signal Si output by the variable phase device 25 is output. The amplifier 24 linearly amplifies the distribution signal S1 with a fixed gain. The variable phase device 25 is amplified by the amplifier 24 with a phase amount corresponding to the phase amount control signal SP3 (or SP5, SP7, hereinafter also referred to as phase amount control signal SP when not distinguished) output from the CPU 13. The phase of the high frequency signal Si is shifted. The synthesizer 26 generates and outputs a high frequency signal S2-3 as a third-order distortion signal ε3 by subtracting the distribution signal S1 output by the variable attenuator 23 from the distribution signal S1 output by the variable phase device 25. ..

【0025】

In this third-order distortion generation circuit 3-3, the variable amplifier 22 amplifies the high-frequency signal Si distributed by the distributor 21 with a gain corresponding to the gain control signal SG3, and the voltage level corresponding to the nonlinear input / output characteristics thereof. The third-order distortion signal ε3 is generated, and the third-order distortion signal ε3 is output to the variable attenuator 23 together with the amplified high-frequency signal Si. Further, the variable attenuator 23 attenuates the output signal of the variable amplifier 22 with an attenuation amount corresponding to the attenuation amount control signal SA3 and outputs the output signal to one input terminal of the synthesizer 26. On the other hand, the amplifier 24 linearly amplifies the high-frequency signal Si with a predetermined fixed gain and outputs it to the variable phase device 25, and the variable phase device 25 outputs the output signal of the amplifier 24 with a phase amount corresponding to the phase amount control signal SP3. The high frequency signal Si) is phase-shifted and output to the other input terminal of the synthesizer 26. Further, the synthesizer 26 subtracts the high frequency signal Si and the third-order distortion signal ε3 input to one input terminal from the high frequency signal Si input to the other input terminal. In this case, the variable attenuator 23 adjusts the power of the high-frequency signal Si input to one input terminal, and the variable phase controller 25 adjusts the phase of the high-frequency signal Si input to the other input terminal. The high-frequency signal Si input to one input terminal and the high-frequency signal Si input to the other input terminal are reliably offset. Therefore, the synthesizer 26 uses only the reverse-phase third-order distortion signal ε3 as the high-frequency signal S2-3 (hereinafter, also referred to as high-frequency signal S2 when the high-frequency signals S2-5 and S2-7 are not distinguished). Output.

【0026】

Further, in the fifth-order distortion generation circuit 3-5, the variable amplifier 22 amplifies the high-frequency signal Si distributed by the distributor 21 with a gain corresponding to the gain control signal SG5, and a voltage corresponding to the nonlinear input / output characteristics thereof. The level third-order distortion signal ε3 and fifth-order distortion signal ε5 are generated, and the third-order distortion signal ε3 and fifth-order distortion signal ε5 are output to the variable attenuator 23 together with the amplified high-frequency signal Si. Further, the variable attenuator 23 attenuates the output signal of the variable amplifier 22 with an attenuation amount corresponding to the attenuation amount control signal SA5 and outputs the output signal to one input terminal of the synthesizer 26. On the other hand, the amplifier 24 linearly amplifies the high frequency signal Si with a predetermined fixed gain and outputs it to the synthesizer 26, and the variable phase device 25 linearly amplifies the high frequency signal Si and outputs the output signal (high frequency) of the amplifier 24 with the phase amount corresponding to the phase amount control signal SP5. The signal Si) is phase-shifted and output to the other input terminal of the synthesizer 26. Further, the synthesizer 26 subtracts the high frequency signal Si, the third-order distortion signal ε3, and the fifth-order distortion signal ε5 input to one input terminal from the high-frequency signal Si input to the other input terminal. In this case, the variable attenuator 23 adjusts the power of the high-frequency signal Si input to one input terminal, and the variable phase controller 25 adjusts the phase of the high-frequency signal Si input to the other input terminal. The high-frequency signal Si input to one input terminal and the high-frequency signal Si input to the other input terminal are reliably offset. Therefore, the synthesizer 26 outputs only the opposite-phase third-order distortion signal ε3 and the fifth-order distortion signal ε5 as the high-frequency signal S2-5.

【0027】

Further, in the 7th-order distortion generation circuit 3-7, the variable amplifier 22 amplifies the high-frequency signal Si distributed by the distributor 21 with a gain corresponding to the gain control signal SG7, and a voltage corresponding to the nonlinear input / output characteristics thereof. Generates the 3rd-order distortion signal ε3, 5th-order distortion signal ε5 and 7th-order distortion signal ε7 of the level, and variably attenuates the 3rd-order distortion signal ε3, 5th-order distortion signal ε5 and 7th-order distortion signal ε7 together with the amplified high-frequency signal Si. Output to device 23. Further, the variable attenuator 23 attenuates the output signal of the variable amplifier 22 with an attenuation amount corresponding to the attenuation amount control signal SA7 and outputs the output signal to one input terminal of the synthesizer 26. On the other hand, the amplifier 24 linearly amplifies the high-frequency signal Si with a predetermined fixed gain and outputs it to the variable phase device 25, and the variable phase device 25 outputs the output signal of the amplifier 24 with a phase amount corresponding to the phase amount control signal SP7. The high frequency signal Si) is phase-shifted and output to the other input terminal of the synthesizer 26. Further, the synthesizer 26 outputs the high frequency signal Si, the third-order distortion signal ε3, the fifth-order distortion signal ε5, and the seventh-order distortion signal ε7 input to one input terminal from the high-frequency signal Si input to the other input terminal. Subtract. In this case, the variable attenuator 23 adjusts the power of the high-frequency signal Si input to one input terminal, and the variable phase controller 25 adjusts the phase of the high-frequency signal Si input to the other input terminal. The high-frequency signal Si input to one input terminal and the high-frequency signal Si input to the other input terminal are reliably offset. Therefore, the synthesizer 26 outputs only the opposite-phase third-order distortion signal ε3, fifth-order distortion signal ε5, and seventh-order distortion signal ε7 as the high-frequency signal S2-7.

【0028】

The vector amount adjustment circuit 4-3 for third-order distortion shifts the phase of the high-frequency signal S2-3 according to the vector amount control signal SV3 output from the CPU 13, and changes the attenuation amount as necessary. The next distortion signal ε3 is output as a high frequency signal S2-3. The 5th-order distortion vector amount adjustment circuit 4-5 shifts the phase of the high-frequency signal S2-5 according to the vector amount control signal SV5 output from the CPU 13, and changes the attenuation amount as necessary. The next-order distortion signal ε3 and the fifth-order distortion signal ε5 are output as high-frequency signals S2-5. The 7th-order distortion vector amount adjustment circuit 4-7 responds to the vector amount control signal SV7 (hereinafter, also referred to as vector amount control signal SV when the vector amount control signals SV3 to SV7 are not distinguished) output from the CPU 13. Then, the phase of the high-frequency signal S2-7 is shifted and the amount of attenuation is changed as necessary to output the third-order distortion signal ε3, the fifth-order distortion signal ε5, and the seventh-order distortion signal ε7 as the high-frequency signal S2-7. ..

【0029】

The output synthesis circuit 6 is a distributor (first distributor in the present invention) 31-3 that divides the high-frequency signal S2-3 output from the vector amount adjustment circuit 4-3 for third-order distortion into two, and a fifth-order distortion. It is output from the distributor (second distributor in the present invention) 31-5 that divides the high frequency signal S2-5 output from the vector amount adjustment circuit 4-5 into two, and the vector amount adjustment circuit 4-7 for 7th order distortion. A distributor 31-7 that divides the high-frequency signal S2-7 into two, a synthesizer 32,33, a vector amount adjustment circuit 34-3,34-5,34-7, a synthesizer 35, and a distributor 36. It is configured with. In this case, the synthesizer 32 corresponds to the first synthesizer in the present invention, and is distributed by the high frequency signal S2-3 (that is, the third-order distortion signal ε3) distributed by the distributor 31-3 and the distributor 31-5. By inputting the high-frequency signal S2-5 (that is, the third-order distortion signal ε3 and the fifth-order distortion signal ε5) and synthesizing the phase-inverted high-frequency signal S2-3 and the high-frequency signal S2-5, that is, high frequency. The high frequency signal S2-3 is subtracted from the signal S2-5 to generate the fifth-order distortion signal ε5. Further, the synthesizer 33 corresponds to the second synthesizer in the present invention, and the high frequency signal S2-5 distributed by the distributor 31-5 and the high frequency signal S2-7 (that is, 3) distributed by the distributor 31-7. By inputting the next-order distortion signal ε3, fifth-order distortion signal ε5, and seventh-order distortion signal ε7) and synthesizing the phase-inverted high-frequency signal S2-5 and high-frequency signal S2-7, that is, the high-frequency signal S2- The high frequency signal S2-5 is subtracted from 7 to generate the 7th-order distortion signal ε7.

【0030】

Further, the vector amount adjustment circuit 34-3 corresponds to the first vector amount adjustment circuit in the present invention, and when the vector amount control signals SVO3 (hereinafter, the vector amount control signals SVO5 to SVO7) output from the CPU 13 are not distinguished, " The phase of the high-frequency signal S2-3 (that is, the third-order distortion signal ε3) is shifted according to the vector quantity control signal SVO), and the attenuation is changed as necessary to synthesize the third-order distortion signal ε3. Output to vessel 35. The vector quantity adjustment circuit 34-5 corresponds to the second vector quantity adjustment circuit in the present invention, and is required to shift the phase of the fifth-order distortion signal ε5 according to the vector quantity control signal SVO5 output from the CPU 13. The amount of attenuation is varied accordingly, and the fifth-order distortion signal ε5 is output to the synthesizer 35. The vector quantity adjustment circuit 34-7 is the vector quantity control signal SVO7 output from the CPU 13. The phase of the 7th-order distortion signal ε7 is shifted according to the phase, and the amount of attenuation is changed as necessary to output the 7th-order distortion signal ε7 to the synthesizer 35. One of the high-frequency signals S2-7 output from the distributor 31-7 is input to the synthesizer (not shown) required when arranging the 9th-order distortion generation series, and is 9th-order. When the distortion generation series is not arranged, it is terminated with a terminating resistor having the same resistance value as the output impedance of the distributor 31-7.

【0031】

The synthesizer 35 inputs and synthesizes the high-frequency signal Si, the third-order distortion signal ε3, the fifth-order distortion signal ε5, and the seventh-order distortion signal ε7 linearly amplified by the linear circuit 5, and thereby synthesizes the drive signal Sd (that is, (Si +). ε3 + ε5 + ε7)) is generated and output. The distributor 36 is composed of, for example, a directional coupler, and outputs a part of the drive signal Sd to the distortion detector 15.

【0032】

Further, the ROM 14 corresponds to each power value and each frequency of the high-frequency signal Si and each combination of the detection temperature detected by the temperature sensor 12, and each variable amplifier 22 and variable attenuator in each distortion generation circuit 3. The gain control amount, attenuation control amount, and phase control amount for 23 and the variable phase controller 25, and the vector control amount for each vector amount adjustment circuit 4 are stored. Further, the ROM 14 stores a value that can most compensate for the high-order intermodulation distortion generated when the high-frequency amplifier circuit 51 amplifies the level and phase of each distortion signal ε output by the synthesizer 35. On the other hand, the CPU 13 outputs a gain control signal SG to each variable amplifier 22 and a gain control signal SG to each variable attenuator 23 based on the detection signals output from the PF detector 11 and the temperature sensor 12, respectively. Attenuation control signal SA, phase amount control signal SP for each variable phase controller 25, vector amount control signal SV for each vector amount adjustment circuit 4. Is output. Further, the CPU 13 has a vector amount adjustment circuit 34-3, so that the higher-order intermodulation distortion (non-linear distortion) included in the output signal of the high-frequency amplifier circuit 51 is reduced based on the detection signal of the distortion detector 15 described later. Control each adjustment amount of 34-5 and 34-7. The distortion detector 15 determines one of the distortion signal ε included in the drive signal (output signal) Sd output from the output synthesis circuit 6 and the higher-order intermodulation distortion included in the output signal of the high-frequency amplifier circuit 51. To detect.

【0033】

Next, the overall operation of the nonlinear distortion compensation circuit 1 will be described.

【0034】

First, when the high-frequency signal Si is input, the PF detector 11 detects the power value and frequency of the high-frequency signal Si and outputs it to the CPU 13 as a detection signal. Further, the temperature sensor 12 detects the ambient temperature and outputs the detection signal to the CPU 13. Next, the CPU 13 constantly monitors each input detection signal, and the gain control amount for each variable amplifier 22 corresponding to the combination of the detection signals, the attenuation control amount for each variable attenuator 23, and each variable phase device 25. The phase control amount for each vector amount adjustment circuit 4 and the phase control amount and attenuation control amount for each vector amount adjustment circuit 4 are read from the ROM 14, and the gain control signal SG, attenuation amount control signal SA, and phase amount control according to each control amount are read in real time. The signal SP and the vector amount control signal SV are output to each corresponding circuit.

【0035】

Next, in each distortion generation circuit 3, each variable amplifier 22 amplifies the distributed high-frequency signal Si with a gain based on each gain control signal SG, and each variable attenuator 23 attenuates the output signal of the variable amplifier 22. It is attenuated by the amount of attenuation based on the quantity control signal SA and output to one input section of each synthesizer 26. Further, each amplifier 24 amplifies the distributed high frequency signal Si with a predetermined fixed gain, and each variable phase device 25 shifts the phase of the output signal of the amplifier 24 by a phase amount based on each phase amount control signal SP. Is output to the other input section of each synthesizer 26. Therefore, the synthesizer 26 of the third-order distortion generation circuit 3-3 outputs the third-order distortion signal ε3 as the high-frequency signal S2-3. Similarly, the synthesizer 26 of the 5th-order distortion generation circuit 3-5 outputs the 3rd-order distortion signal ε3 and the 5th-order distortion signal ε5 as the high-frequency signal S2-5, and the synthesizer of the 7th-order distortion generation circuit 3-7. 26 outputs the third-order distortion signal ε3, the fifth-order distortion signal ε5, and the seventh-order distortion signal ε7 as the high-frequency signal S2-7.

【0036】

Subsequently, the vector amount adjustment circuit 4-3 for third-order distortion shifts and attenuates the phase of the high-frequency signal S2-3 with the phase amount and the attenuation amount based on the vector amount control signal SV3, and the distributor in the output synthesis circuit. Output to 31-3. Similarly, the 5th-order distortion vector amount adjustment circuit 4-5 shifts and attenuates the phase of the high-frequency signal S2-5 with the phase amount and attenuation amount based on the vector amount control signal SV5 to the distributor 31-5. Output, and the 7th-order distortion vector amount adjustment circuit 4-7 shifts the phase of the high-frequency signal S2-7 with the phase amount and attenuation amount based on the vector amount control signal SV7, attenuates it, and outputs it to the distributor 31-7. To do. Next, each distributor 31 divides the high frequency signal S2 into two and outputs the signal S2. In addition, the synthesizer 32 synthesizes the high-frequency signals S2-3 and S2-5 to output the fifth-order distortion signal ε5, and the synthesizer 33 synthesizes the high-frequency signals S2-5 and S2-7 to output the seventh-order distortion signal ε7. Is output. Next, each vector amount adjusting circuit 34 shifts and attenuates the phase of the high frequency signal S2 with the phase amount and the attenuation amount based on each vector amount control signal SVO, and outputs the phase to the synthesizer 35. Further, the linear circuit 5 linearly amplifies the distribution signal S1-1 (high frequency signal Si) distributed by the input distributor 2 with a predetermined gain and outputs the distribution signal S1-1 to the synthesizer 35. Subsequently, the synthesizer 35 synthesizes the third-order distortion signal ε3, the fifth-order distortion signal ε5, the seventh-order distortion signal ε7, and the high-frequency signal Si, and outputs the drive signal Sd.

【0037】

Next, the high-frequency amplifier circuit 51 power-amplifies the drive signal Sd and outputs the output signal So. At this time, in the high-frequency amplifier circuit 51, the third-order distortion signal ε3, the fifth-order distortion signal ε5, and the seventh-order distortion signal ε7, which are out of phase with the higher-order intermodulation distortion generated when the high-frequency signal Si is amplified, are the drive signals Sd. Since it is added in advance to, the output signal So in which the high-order intermodulation distortion from the 3rd order to the 7th order is extremely suppressed is generated. In this case, the distortion detector 15 detects the distortion signal ε included in the drive signal Sd output from the distributor 36 and outputs it to the CPU 13 as the distortion detection signal Sε. Further, the CPU 13 determines the vector amount of each vector amount adjusting circuit 34 so that the level and phase of each distortion signal ε are equal to the level and phase stored in advance in the ROM 14 based on the input distortion detection signal Sε. To adjust. In this case, the ROM 14 stores in advance the level and phase of each distortion signal ε that can most suppress the high-order intermodulation distortion generated by the high-frequency amplifier circuit 51. Therefore, the high-order intermodulation distortion generated by the high-frequency amplifier circuit 51 is surely compensated and sufficiently suppressed.

【0038】

As described above, according to this non-linear distortion compensation circuit 1, efficiency is reduced by synthesizing the distortion signal ε from the third-order distortion signal ε3 to the seventh-order distortion signal ε7 and the high-frequency signal Si by the predistortion method. From the major 3rd-order intermodulation distortion to the 7th-order intermodulation distortion among the high-order intermodulation distortions generated when the high-frequency amplifier circuit 51 amplifies the high-frequency signal without causing the equipment cost to rise due to the adjustment cost. Can be uniformly and sufficiently suppressed. In addition, the CPU 13 reads the adjustment amount corresponding to each detection signal detected by the PF detector 11 and the temperature sensor 12 from the ROM 14, and adjusts each variable amplifier 22, variable attenuator 23, variable phase device 25, and each vector amount. By controlling with the adjustment amount read out to the circuit 4, the third-order intermodulation distortion as the non-linear distortion generated in the high-frequency amplifier circuit 51 according to the frequency of the high-frequency signal Si, the power of the high-frequency signal Si, and the internal temperature. It is possible to appropriately generate a third-order distortion signal ε3 to a seventh-order distortion signal ε7 that can sufficiently suppress high-order intermodulation distortion from to 7th-order intermodulation distortion. As a result, higher-order intermodulation distortion can be uniformly, sufficiently, and automatically suppressed. Further, the CPU 13 adjusts the vector amount of each vector amount adjusting circuit 34 based on the drive signal Sd or the output signal So so that the higher-order intermodulation distortion contained in the output signal So is reduced to the maximum. The amplifier circuit 51 can generate an output signal So in which higher-order intermodulation distortion is most suppressed.

【0039】

The present invention is not limited to the configuration shown in the embodiment of the above invention, and can be appropriately modified. For example, in the nonlinear strain compensation circuit 1 shown in FIG. 1, a configuration example having an Nth-order distortion generation sequence from a third-order distortion generation sequence has been described, but it is not necessary to have all the distortion generation sequences, and at least the third-order distortion. The high frequency generated when the high frequency amplifier circuit 51 amplifies the high frequency signal Si by including the generation series and any one or more distortion generation series from the 5th order distortion generation series to the Nth order distortion generation series. Higher-order intermodulation distortion, which is desired to be suppressed, can be sufficiently suppressed. Further, as the high-order intermodulation distortion, since the third-order intermodulation distortion and the fifth-order intermodulation distortion cause the most harmful effects, it is preferable to have at least a third-order distortion generation series and a fifth-order distortion generation series. The configuration in this case can be easily configured by omitting the nonlinear strain compensation circuits 1 to 7th-order strain generation series shown in the embodiment of the present invention. Further, the present invention can be effectively applied not only to the application of the pre-distortion type nonlinear distortion compensation circuit but also to the circuit for generating the distortion signal ε in the forward type nonlinear distortion compensation apparatus.

【0040】

Further, in this nonlinear distortion compensation circuit 1, the distortion signal ε is generated by utilizing the nonlinear input / output characteristic inside the distortion generation circuit 3, but the input / output amplitude characteristic (the input / output amplitude characteristic is utilized by utilizing the nonlinear input / output characteristic of the diode. A distortion signal ε having an amplitude corresponding to the power series expansion approximation) may be generated, or the magnitude of each orthogonal component is controlled by a vector synthesis method (a method of simultaneously compensating for the amplitude and phase nonlinear characteristics of the distortion signal ε). The distortion signal ε may be generated by directly controlling the vector amount of the distortion signal by performing vector synthesis. Further, in the embodiment of the present invention, as the detectors in the present invention, the PF detector 11 that detects the frequency and power of the high frequency signal Si, and the temperature sensor 12 that detects the internal temperature of the nonlinear strain compensation circuit 1 are used. However, the detectors in the present invention include the frequency of the high-frequency signal Si, the power of the high-frequency signal Si, the temperature inside or near the nonlinear amplifier circuit, and the inside or near the high-frequency amplifier circuit 51. A detection circuit configuration that detects at least one of the temperatures can be adopted.

【0041】

[Effect of the invention]

As described above, according to the non-linear distortion compensation circuit according to the present invention, an N-th order distortion signal capable of compensating for N-th order intermodulation distortion as a non-linear distortion and an input high frequency signal are combined based on the input high frequency signal. By outputting as an output signal, the high-order intermodulation distortion generated when the high-frequency amplifier circuit amplifies the high-frequency signal is eliminated without reducing the efficiency of the high-frequency amplifier circuit and increasing the equipment cost due to the adjustment cost. It can be suppressed uniformly and sufficiently. In this case, by providing a plurality of distortion generation circuits, linear circuits, and output synthesis circuits, each Nth-order distortion signal can be reliably generated based on the input high-frequency signal, and each Nth-order distortion generated can be reliably generated. The output signal can be reliably generated by synthesizing the signal and the linearly amplified input high frequency signal.

【0042】

Further, according to the non-linear distortion compensation circuit according to the present invention, a linear circuit, a third-order distortion generation circuit and a fifth-order distortion generation circuit are provided, and the first distributor of the output synthesis circuit distributes the output signal of the third-order distortion generation circuit. Then, the second distributor distributes the output signal of the fifth-order distortion generation circuit, and the first synthesizer subtracts the distribution signal distributed by the first distributor from the distribution signal distributed by the second distributor. The second-order distortion signal is generated, and the second synthesizer synthesizes the third-order distortion signal distributed by the first distributor, the fifth-order distortion signal generated by the first synthesizer, and the linearly amplified input high-frequency signal. By outputting the output signal, a third-order distortion signal, a fifth-order distortion signal, and a linearly amplified input high-frequency signal can be reliably generated based on the input high-frequency signal, and a third-order as a non-linear distortion can be generated. It is possible to reliably generate a distorted signal that can sufficiently suppress intermodulation distortion and fifth-order intermodulation distortion.

【0043】

Further, according to the non-linear distortion compensation circuit according to the present invention, a vector amount adjustment circuit for third-order distortion and a fifth-order distortion generation circuit configured so that the vector amount of the output signal output by the third-order distortion generation circuit can be adjusted. By providing a vector amount adjustment circuit for 5th order distortion configured to be able to adjust the vector amount of the output signal output by, the 3rd order cross modulation distortion and Nth order as non-linear distortion are provided based on the input high frequency signal. It is possible to more reliably generate a distorted signal that can sufficiently compensate and suppress cross-modulation distortion.

【0044】

Further, according to the non-linear distortion compensation circuit according to the present invention, a first vector amount adjusting circuit configured to be able to adjust the vector amount of the third-order distortion signal distributed by the first distributor, and a first synthesizer generate the vector amount. By providing a second vector amount adjustment circuit configured to be able to adjust the vector amount of the fifth-order distortion signal, by adjusting both vector amount adjustment circuits, third-order intermodulation distortion as non-linear distortion and It is possible to generate a distortion signal that can more reliably compensate and suppress the fifth-order intermodulation distortion.

【0045】

Further, according to the non-linear distortion compensation circuit according to the present invention, the control circuit inputs the detection signal of the detection circuit, reads out each adjustment amount corresponding to the detection signal from the memory, and also has the third-order distortion vector amount adjustment circuit and By controlling each read-out adjustment amount for the 5th-order distortion vector amount adjustment circuit, the frequency of the input high-frequency signal, the power of the input high-frequency signal, the temperature inside or near the non-linear distortion compensation circuit, and the compensated As a result, a distortion signal capable of sufficiently suppressing the third-order intermodulation distortion and the fifth-order intermodulation distortion as non-linear distortion can be appropriately generated depending on at least one of the temperatures inside or in the vicinity of the high-frequency amplifier circuit. High-order intermodulation distortion generated when a high-frequency amplifier circuit amplifies a high-frequency signal can be uniformly, sufficiently, and automatically suppressed.

【0046】

Further, according to the non-linear distortion compensation circuit according to the present invention, the control circuit adjusts the adjustment amount of the first vector amount adjustment circuit and the adjustment amount of the second vector amount so that the non-linear distortion included in the output signal of the compensated high-frequency amplifier circuit is reduced. By controlling the adjustment amount of the circuit, it is possible to uniformly, sufficiently, and automatically suppress the high-order intermodulation distortion generated when the high-frequency amplifier circuit amplifies the high-frequency signal.

【0047】

Further, according to the non-linear distortion compensation circuit according to the present invention, by configuring each vector amount adjustment circuit so that the attenuation amount and the phase amount of the corresponding distortion signal can be adjusted, the third-order intermodulation distortion as the non-linear distortion and 5 It is possible to generate a distortion signal that can more reliably compensate and suppress the next intermodulation distortion.

[Simple explanation of drawings]

[Figure 1]

It is a basic block diagram of the nonlinear distortion compensation circuit 1 which concerns on embodiment of this invention.

[Figure 2]

It is a spectrum figure which shows the signal component of the drive signal Sd for demonstrating the operation principle of the nonlinear distortion compensation circuit 1.

[Fig. 3]

It is a spectrum diagram for demonstrating the operation principle of the nonlinear distortion compensation circuit 1, and is the spectrum diagram which shows the signal component of the output signal So generated by the high frequency amplifier circuit 51 in the state which is not distortion compensation.

[Fig. 4]

It is a spectrum diagram for demonstrating the operation principle of the nonlinear distortion compensation circuit 1, and is the spectrum diagram which shows the signal component of the output signal So generated by the high frequency amplifier circuit 51 in the state of distortion compensation.

[Fig. 5]

It is a block diagram which shows the specific structure of the nonlinear distortion compensation circuit 1 which concerns on embodiment of this invention.

[Fig. 6]

It is a block diagram which shows the structure of the conventional high frequency power amplification apparatus 61.

[Fig. 7]

It is a block diagram which shows the structure of the conventional nonlinear distortion compensation circuit 41.

[Explanation of symbols]

1 Non-linear distortion compensation circuit 2 Input distributor 3-3 ~ 3-N distortion generation circuit 4-3 ~ 4-N, 34-3,34-5 Vector quantity adjustment circuit 5 Linear circuit 6 Output synthesis circuit 11 P / F detector 12 temperature sensor 13 CPU 14 ROM 15 Strain detector 31-3,31-5 Distributor 32,33,35 synthesizer ε3 ~ εN distortion signal Sd drive signal Si high frequency signal So output signal