JP2000252763A - Distortion compensation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain miniaturization of a device or the like in the distortion compensation device that compensate ternary distortion produced from its amplifier. SOLUTION: The distortion compensation device consists of a 3dB coupler Q1 having, e.g. 4 terminals. The 1st terminal P1 receives a signal inputted to or outputted from an amplifier, the 2nd and 3rd terminals P2, P3 are each provided with a ternary distortion generator that generates a ternary distortion signal with an amplitude and a phase so as to cancel the ternary distortion produced in the amplifier in accordance with the input signal, and the 4th terminal P4 synthesizes the ternary distortion generated from the ternary distortion generator of the 2nd and 3rd terminals P2, P3 with the input signal and outputs the resulting signal. Thus, the ternary distortion generated from the amplifier can be compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distortion compensator for compensating for third-order distortion generated in an amplifier, and more particularly, to a distortion compensator comprising a four-terminal power divider having two third-order distortion generators. The present invention relates to a distortion compensating device that realizes miniaturization and the like.

[0002]

2. Description of the Related Art It is known that, for example, when a signal is amplified by an amplifier, higher-order distortion is generated. In particular, it is known that third-order distortion generated by the amplifier has a large adverse effect on signal processing. I have. Here, assuming that a signal of a certain frequency input to the amplifier is a basic signal, the amplifier has a frequency of 3 different from the basic signal in accordance with the basic signal.
The next distortion occurs.

As a method of compensating for the third-order distortion in such an amplifier, for example, a third-order distortion for distortion compensation is generated at a stage preceding the amplifier, and the third-order distortion cancels out the third-order distortion generated in the amplifier. There is a way. As a configuration of a distortion compensating apparatus for generating such third-order distortion for distortion compensation, for example, a third-order distortion generated by a phase modulator is combined with a linear signal in an appropriate phase relationship and output to a subsequent-stage amplifier. One that uses a third-order distortion generator, a wideband phase shifter, or the like has been considered.

[0004]

However, in the conventional distortion compensating apparatus, for example, a signal processing system for handling an input basic signal and a signal processing system for generating a third-order distortion are separately provided, and these two signal processing systems are provided. Since the synthesizer for synthesizing the output signal (basic signal and third-order distortion signal) from the system is further provided separately, the device becomes large-scale, which is not suitable for miniaturization. Was.

In a conventional distortion compensator, for example, 3
Since a signal loss at the time of generating the second-order distortion is large, a wideband LNA (Low Noise Amplifier) that amplifies the third-order distortion is used.
ier), and a complicated external control circuit or a storage circuit that stores control information because high-precision control is required to generate a third-order distortion suitable for distortion compensation, for example. Had to be provided.

[0006] In view of the above, it has been desired to develop a distortion compensator suitable for miniaturization as described above, and also to realize, for example, reduction in power consumption. SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and has as its object to provide a distortion compensating apparatus suitable for miniaturization in a distortion compensating apparatus for compensating for third-order distortion generated in an amplifier. I do. Further, the distortion compensating device of the present invention can also realize, for example, reduction of power consumption. Further, in the distortion compensating apparatus of the present invention, it is possible to suppress the generation of fifth-order distortion by lowering the level of the input signal, for example.

[0007]

In order to achieve the above object, a distortion compensator according to the present invention compensates for third-order distortion generated in an amplifier by the following configuration. That is, the distortion compensator according to the present invention includes a power divider having four terminals, a first terminal for inputting a signal input to or output from the amplifier, and a second terminal and a third terminal for inputting. Generating a third-order distortion having an amplitude and a phase that cancels out the third-order distortion generated in the amplifier according to the signal;
A fourth-order distortion generator is provided, and the fourth terminal combines and outputs the third-order distortion generated by the third-order distortion generators of the second terminal and the third terminal with the input signal.

Accordingly, in the present invention, since the distortion compensating device is constituted by the four-terminal power distributor provided with the two third-order distortion generators, for example, the distortion compensating device can be replaced by a coupler unit using one such coupler. It can be configured and is very suitable for miniaturization of the device. Further, since the configuration is such that the third-order distortion generated by the two third-order distortion generators is combined and output, for example, even if the level of the input signal is lowered, a large 3rd-order distortion is generated.
The next-order distortion can be generated, and the generation of the fifth-order distortion can be suppressed. A specific example of how to set the amplitude and phase of the tertiary distortion generated by the tertiary distortion generator will be described in an embodiment described later.

Here, "the first terminal is to be input to the amplifier or to input the signal output from the amplifier" means that the distortion compensator according to the present invention is provided at the preceding stage of the amplifier and the signal input to the amplifier is input to the amplifier. This indicates that the signal may be input from one terminal, or a signal output from the amplifier provided at the subsequent stage of the amplifier may be input from the first terminal. In any case, the third-order distortion generated in the amplifier can be compensated for by the distortion compensator generating the third-order distortion that cancels out the third-order distortion generated in the amplifier.

The number of amplifiers to be subjected to distortion compensation is not necessarily limited to one. For example, the number of amplifiers generated by a plurality of amplifiers provided in the preceding stage of the distortion compensating device is not limited to one.
A second-order distortion compensating device, a third-order distortion generated by a plurality of amplifiers provided in a subsequent stage, or a first-order distortion compensating device provided in a preceding stage. It is also possible to adopt a configuration that compensates for third-order distortion generated by one or more amplifiers and one or more amplifiers provided at the subsequent stage.

When the distortion compensator compensates for the third-order distortion generated by the plurality of amplifiers as described above, the distortion compensator can compensate for the total sum of the third-order distortion generated by the plurality of amplifiers. Generate third order distortion. In the present invention, “to cancel the third-order distortion generated by the amplifier” means not only the mode of canceling the third-order distortion generated by one amplifier but also the three-dimensional distortion generated by a plurality of amplifiers as described above.
This is a concept including a mode for canceling the sum of the secondary distortions.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A distortion compensating apparatus according to one embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration example of a distortion compensation device according to the present example. As shown in the figure, the distortion compensating apparatus of the present example is configured by a 3 dB coupler Q having four terminals such as an input terminal T1, an output terminal T2, a 90 ° terminal, and a 0 ° terminal.
The third-order distortion generators Z1 and Z, which generate third-order distortion using, for example, a semiconductor active element, are provided at the terminal and the 0 ° terminal, respectively.
2 are connected.

In this embodiment, as an example, a case is shown in which the distortion compensating apparatus of the present embodiment is applied to a mobile phone base station and a terminal provided in a communication system. A case will be described in which the third-order distortion generated by the provided amplifier is compensated by the distortion compensating device of the present embodiment. In this example, the distortion compensating device is provided before the amplifier to be subjected to distortion compensation, and a basic signal (in this example, a high-frequency signal communicated by a mobile phone terminal or the like) input to the amplifier is supplied to the input terminal described above. The configuration and the like of the distortion compensator will be described by taking as an example a case where the input is made from T1. An example in which the distortion compensating device is provided at a stage subsequent to the amplifier will be described later with reference to FIG.

In the distortion compensating apparatus shown in FIG. 1, two tertiary distortion generators Z1 and Z2 generate tertiary distortion in response to the input of the basic signal from the input terminal T1.
The reflected wave of the third-order distortion generated by the dB coupler Q and the basic signal are combined and output from the output terminal T2.

Here, in the above-mentioned 3 dB coupler Q, for example, when both the 90 ° terminal and the 0 ° terminal are short-circuited or opened, the signal wave is totally reflected, and the input terminal T1
Can be output from the output terminal T2 with ideal efficiency. For this reason, it is assumed that a third-order distortion generator is connected in series to only one of the 90 ° terminal and the 0 ° terminal, and a third-order distortion generator is connected to the other terminal (the 90 ° terminal or the 0 ° terminal). 1 and the output terminal of the third-order distortion generator (for example, when a third-order distortion generator is connected to the 90 ° terminal, a terminal corresponding to terminal T3 in FIG. 1; When a third-order distortion generator is connected, the terminal (corresponding to terminal T5 in the figure) is short-circuited or opened, so that the amount of main signal passing attenuation can be reduced. However, in such a configuration, for example, a large 3
When the next-order distortion is generated, the fifth-order distortion generated accompanying this may increase.

Therefore, in the distortion compensator of this embodiment, as shown in FIG. 1, the third-order distortion generators Z1 and Z2 are connected to both the 90 ° terminal and the 0 ° terminal, respectively. In the configuration, the level of the main signal is attenuated, and the third-order distortion generated by the two third-order distortion generators is combined and output. Next-order distortion can be generated. For this reason, in the distortion compensating apparatus of the present example, it is possible to suppress the generation of the fifth-order distortion by lowering the level of the input signal, and to reduce the ratio between the third-order distortion and the main signal, for example. It is possible.

Further, when the 3 dB coupler Q is used as in the present embodiment, even if, for example, even-order distortion is generated parasitically together with the third-order distortion in the third-order distortion generators Z 1 and Z 2, It is preferable because even-order distortion can be removed, and unnecessary signal components such as a leaky wave of a local signal or another system (for example, a communication system) can be removed.

Further, the distortion compensator of the present embodiment is provided with a control voltage terminal T4 for controlling the amplitude of the third-order distortion generated by each of the third-order distortion generators Z1 and Z2. The amplitude ratio between the third-order distortion and the basic signal can be controlled by the magnitude of the DC voltage applied to the terminal T4. In addition, the variation of the pass voltage in the distortion compensator is small and stable even by changing the DC voltage.

Next, a more specific configuration example of the distortion compensating apparatus of this embodiment will be described. FIG. 2 shows an example of a circuit configuration of the distortion compensating apparatus of the present embodiment, in which a 3 dB coupler Q1, an input terminal (IN) P1, a 90 ° terminal P2, a 0 ° terminal P3, an output terminal (ISO) P4, and a third order. The control voltage terminal P5 of the distortion generator is the same as that shown in FIG.

In this example, a power divider having four terminals according to the present invention is constituted by the 3 dB coupler Q1, and a first terminal for inputting an signal to the amplifier or inputting a signal outputted from the amplifier is constituted by the input terminal P1. And the 90 ° terminal P
2 constitutes a second terminal including a third-order distortion generator that generates a third-order distortion according to an input signal, and includes a 0 ° terminal P3 including a third-order distortion generator that generates a third-order distortion according to the input signal. A third terminal is configured, and the third terminal generated by the third-order distortion generator of the second terminal and the third terminal by the output terminal P4.
A fourth terminal is provided for combining and outputting the second-order distortion and the input signal.

A circuit configuration example of the third-order distortion generator connected to the 90 ° terminal P2 will be described. This third-order distortion generator has 9
A fixed resistor R1 connected to the 0 ° terminal P2, a capacitor C1 connected in series with the fixed resistor R1, and diode units D1 and D2 connected in anti-parallel to the capacitor C1.
And two capacitors C2 and C3 connected in series with the diode units D1 and D2, and these capacitors C2 and C3.
3 and a diode part D on one side.
1 and a fixed resistor R2 connected between the capacitor C2.
And a capacitor C5 for grounding the fixed resistor R2, and a fixed resistor R3 for grounding between the other diode portion D2 and the capacitor C3. The fixed resistor R2 is connected to the one diode portion D1. The control voltage terminal P5 is connected via the control voltage terminal P5.

The above-mentioned fixed resistor R1 is a matching resistor for matching the impedance of the 90 ° terminal P2 and the third-order distortion generator. The three capacitors C1 to C3 block a DC voltage and short-circuit at a high frequency. It is a voltage blocking capacitor, and a DC voltage blocking capacitor that terminates or opens at high frequency is used as the capacitor C4. Further, the diode units D1 and D2 are provided with a Schottky barrier diode or the like which is a distortion generating element connected in series. For example, when a high-frequency signal is input, the Schottky barrier diode or the like generates third-order distortion. Has a function. Further, a bias circuit for the diode portions D1 and D2 is constituted by the two resistors R2 and R3 which are high-frequency open resistors and the capacitor C5 which is a high-frequency cut-off capacitor. This bias circuit realizes a high-frequency open or short circuit. Have been.

Here, the above-mentioned diode sections D1, D2
However, the two diode units do not necessarily have to be connected in anti-parallel. For example, only one diode unit may be provided. However, if two diode units are provided and connected in anti-parallel as in this example, the temperature change It is preferable because characteristic fluctuations due to the above can be reduced. Also, the diode section D
1, the number of diodes provided in D2 is not particularly limited, and is set based on, for example, input power or an amplitude ratio between a required output wave and third-order distortion.

If the capacitor C4 terminates at a high frequency, for example, a reflected wave can be generated at the connection point between the capacitor C1 and the diode portions D1 and D2, while the capacitor C4 causes a high frequency. When open, for example, reflected waves can be generated between the capacitors C2 and C3 and the capacitor C4, and a preferred configuration can be used depending on the amplifier to be subjected to distortion compensation.

In the third-order distortion generator having the above configuration,
In response to the input of the basic signal from the input terminal P1 to the 90 ° terminal P2, the diode units D1 and D2 can generate third-order distortion with respect to the basic signal, and the reflected wave including the generated third-order distortion To the output terminal P4. Further, in the third-order distortion generator of this example, by controlling the DC voltage from the control voltage terminal P5, the amplitude of only the generated third-order distortion can be variably controlled. Further, in the third-order distortion generator of the present example, the phase of the reflected signal changes according to the capacitance value of the capacitor C4, so that the phase of the third-order distortion can be adjusted by this capacitance value.

The 0 ° terminal P3 of this embodiment has the above-mentioned 9
A third-order distortion generator having a circuit configuration similar to that of the third-order distortion generator connected to the 0 ° terminal P2 is connected.
Similarly to the above, the secondary distortion generator includes a fixed resistor R4 connected to the 0 ° terminal P3, a capacitor C6 connected in series with the fixed resistor R4, and a diode unit D3 connected in anti-parallel to the capacitor C6. D4 and each diode section D
3, two capacitors C7, C8 connected in series with D4
A capacitor C9 for grounding these capacitors C7 and C8, a fixed resistor R5 connected between one diode portion D3 and the capacitor C7, a capacitor C5 for grounding the fixed resistor R5, and the other diode portion. A fixed resistor R6 is provided between D4 and the capacitor C8 to ground, and a control voltage terminal P5 is connected to the one diode section D3 via the fixed resistor R5. In this example, the capacitor C5 and the control voltage terminal P5 are shared by the third-order distortion generator connected to the 90 ° terminal P2 and the third-order distortion generator connected to the 0 ° terminal P3.

In the third-order distortion generator connected to the 0 ° terminal P3, as in the above-described third-order distortion generator connected to the 90 ° terminal P2, the basic signal is supplied from the input terminal P1 to the 0 ° terminal P3. In response to the input, the diode section D
Third, a third-order distortion with respect to the basic signal can be generated at D4, and a reflected wave including the generated third-order distortion can be output to the output terminal P4. Also in this third-order distortion generator, the amplitude of only the generated third-order distortion can be variably controlled by controlling the DC voltage from the control voltage terminal P5. Also in this tertiary distortion generator, the phase of the reflected signal changes according to the capacitance value of the capacitor C9, so that the phase of the tertiary distortion can be adjusted by this capacitance value.

Here, as the amplitude of the third-order distortion generated by the above-described two third-order distortion generators, an amplitude that cancels out the third-order distortion generated by the amplifier to be subjected to distortion compensation is set. Theoretically, the amplitude ratio between the basic signal input to the distortion compensator and the third-order distortion generated by the distortion compensator is
By setting the same value as the amplitude ratio between the basic signal input to the amplifier to be distortion-compensated and the third-order distortion generated in the amplifier, the amplitude related to the amplitude for canceling the third-order distortion generated in the amplifier is set. Can meet requirements. In an actual apparatus, the amplitude of the third-order distortion generated by the third-order distortion generator may be arbitrarily set according to the required accuracy of distortion compensation or the like.

As the phase of the third-order distortion generated by the two third-order distortion generators, the phase difference between the basic signal and the third-order distortion in the distortion compensator is generated by the amplifier to be subjected to distortion compensation. The phase difference is set so as to cancel the third-order distortion. Theoretically, the phase difference between the basic signal output from the distortion compensator and the third-order distortion is equal to the phase difference between the basic signal input to the distortion-compensation target amplifier and the third-order distortion generated by the amplifier. By setting them so as to have a relationship of opposite phase (a value shifted by 180 °), it is possible to satisfy a requirement relating to a phase for canceling third-order distortion generated in the amplifier.

Specifically, for example, if the phase difference of the third-order distortion with respect to the basic signal in the amplifier is α, the phase difference of the third-order distortion with respect to the basic signal in the distortion compensator is (α + 1).
80 °), and in the present example, the above-described relationship of the opposite phases refers to such a relationship. In an actual device, the phase of the third-order distortion generated by the third-order distortion generator may be arbitrarily set according to the required accuracy of distortion compensation or the like. By satisfying the requirements of the amplitude and the phase of the third-order distortion generated by the third-order distortion generator, the distortion compensating apparatus cancels out the third-order distortion generated by the amplifier to be subjected to distortion compensation. Can be generated.

As described above, in the distortion compensator of this embodiment,
Third-order distortion is generated in the diode units D1 to D4 by the 3 dB-attenuated main signal output to the respective third-order distortion generators from the 90 ° terminal P2 and the 0 ° terminal P3 of the 3dB coupler Q1, and includes the third-order distortion. The reflected wave is again 90 ° terminal P2
When the signal is input to the 0 ° terminal P3, a stable signal including the third-order distortion according to the signal input from the input terminal P1 can be output from the output terminal P4. Further, as described above, in the distortion compensator of the present example, the two tertiary distortion generators cancel the tertiary distortion generated by the amplifier in accordance with the input signal (the basic signal in this example) and the amplitude and phase. Is generated, and the third-order distortion and the input signal are combined and output from the output terminal P4, whereby the third-order distortion generated in the amplifier can be compensated.

As an example, generally, when the power consumption of the amplifier is reduced, the intercept point IP3 is reduced (that is, the ratio of the third-order distortion included in the output signal is increased). By applying the device to compensate for third-order distortion, the apparent intercept point IP3 can be increased (ie, the proportion of third-order distortion included in the output signal can be reduced), such that, for example, output saturation Even when an amplifier with a low level is used, a high-frequency amplifier with low distortion is realized, which can contribute to miniaturization, low power consumption, and low cost of these devices.

The extent to which the third-order distortion generated by the amplifier can be compensated (distortion improvement amount) varies depending on the control of the DC voltage applied to the control voltage terminal P5 of the third-order distortion generator. In the configuration using the 3 dB coupler Q1 as described above, for example, even when the DC voltage is fixedly set, it is possible to always obtain a distortion improvement amount of about 6 dB.
3 corresponds to an increase of 3 dB, and the power consumption can be reduced to about half as compared with the case where distortion compensation is not performed. Further, as described above, since the 3 dB coupler Q1 is used in this example, even when distortion of even-order occurs in the diode units D1 to D4, such a basic signal and the third-order distortion are generated. It is possible to remove (attenuate) signals in frequency bands other than the above, thereby removing even-order distortion generated.

In the distortion compensator of this embodiment, the phase of the third-order distortion generated by the diode units D1 to D4 of the third-order distortion generator is usually the third-order distortion generated by the amplifier to be subjected to distortion compensation at the subsequent stage. Has an inverse relationship (the above-described inverse phase relationship) with the phase of the third-order distortion generator. In this example, for example, the capacitance values of the capacitors C4 and C9 provided in the third-order distortion generator are fixedly set. In the present invention, for example, the capacitors C4 and C9 may be configured by variable capacitors, and the capacitance values of the capacitors C4 and C9 may be variably controlled. If the configuration is such that the phase of the third-order distortion can be variably controlled in this manner, for example, according to the fact that the actual Schottky barrier diode and the amplifier to be subjected to distortion compensation have unique distortion characteristics,
Ideal distortion compensation can be realized by variably adjusting a slight phase error caused by such distortion characteristics.

Similarly, in adjusting the amplitude of the third-order distortion generated by the third-order distortion generator, it is not always necessary to use a configuration in which the amplitude can be variably controlled. That is, in the present invention, if the amplitude of the third-order distortion generated by the third-order distortion generator is set so as to be able to cancel out the third-order distortion generated by the amplifier to be compensated for distortion, the amplitude is increased. May be fixedly set.

As described above, the distortion compensating apparatus of the present embodiment
Since the distortion compensator is composed of a coupler having three third-order distortion generators, for example, a distortion compensator can be composed of a coupler unit using one such coupler, and is very suitable for miniaturization of the apparatus. . In the case of this example, by realizing such a small size of the distortion compensating device, it is possible to reduce the weight of a mobile phone terminal or the like provided with the distortion compensating device, and to carry the mobile phone terminal or the like. Can be convenient.

Further, as described above, the distortion compensating apparatus of this embodiment can reduce power consumption. Also,
As described above, in the distortion compensating apparatus of the present embodiment, since the third-order distortion generated by the two third-order distortion generators is synthesized and output, even when the level of the input signal is lowered, for example, it is relatively high. Large third-order distortion can be generated, and thereby, generation of fifth-order distortion can be suppressed.

Next, a specific example of a configuration for compensating the third-order distortion generated in the amplifier by using the above-described distortion compensating apparatus of the present embodiment will be described. FIG. 3 shows an example of a signal processing unit of, for example, a mobile phone terminal to which the distortion compensating device of the present embodiment is applied. The signal processing unit includes an amplifier (AMP) 1 connected in series and the amplifier of the present embodiment. Distortion compensator 2, amplifier 3, and attenuator (ATT) 4
, An amplifier 5, an attenuator 6, and an amplifier 7. The amplifier 1 is, for example, a low distortion amplifier, and the amplifiers 3, 5, and 7 are, for example, power amplifiers.

In the above-described signal processing section, for example, a frequency-converted modulated signal is input from the input terminal N1 to the amplifier 1, and the signal passes through the distortion compensator 2, the amplifier 3, etc., and is output from the output terminal N2. . In this example, a case is shown in which the third-order distortion generated in the four amplifiers 1, 3, 5, and 7 is collectively compensated by the distortion compensating device 2 described above. That is, the distortion compensator 2 generates and outputs a third-order distortion that cancels out the sum of the third-order distortions generated by the four amplifiers 1, 3, 5, and 7.

Here, (a) to (f) in FIG.
FIG. 3 conceptually shows an example of a spectrum of a basic signal (basic signal wave) and a third-order distortion when such distortion compensation is performed. The horizontal axis represents frequency, and the vertical axis represents signal strength. Is shown. In this example, for convenience of explanation, signals of two frequencies within the frequency band of the modulation signal input to the input terminal N1 are shown as basic signals.

FIG. 7A shows an example of a basic signal input to the input terminal N1. FIG. 3B shows an example of a signal output from the amplifier 1.
The third-order distortion generated by the amplifier 1 is output together with the basic signal. FIG. 3C shows an example of a signal output from the distortion compensator 2. The third-order distortion generated by the distortion compensator 2 is added to the third-order distortion generated by the amplifier 1. Has been output.

FIG. 3D shows an example of a signal output from the amplifier 3. The third-order distortion generated by the amplifier 3 is converted to the third-order distortion output from the distortion compensator 2. It is added and output. FIG. 5E shows an example of a signal output from the amplifier 5. The third-order distortion generated by the amplifier 5 is added to the third-order distortion output from the amplifier 3 and output. ing.

FIG. 3F shows an example of a signal output from the amplifier 7 to the output terminal N2.
It is output in addition to the secondary distortion. As shown in the drawing, the third-order distortion generated by the four amplifiers 1, 3, 5, and 7 is canceled by the third-order distortion generated by the distortion compensating device 2, whereby the third-order distortion is output from the output terminal N2. Can be prevented.

Here, the configuration of the distortion compensating apparatus of the present invention is not necessarily limited to the configuration shown in the above embodiment, and various configurations may be used. In other words, the point is that if it is possible to generate a third-order distortion having an amplitude and a phase that cancels out the third-order distortion generated in the amplifier to be compensated for distortion, and to synthesize and output the third-order distortion and the input signal Good.
As an example, for example, F
ET or the like can also be used. Also, there is no particular limitation on the configuration of the circuit for adjusting the amplitude of the third-order distortion. For example, various circuit configurations that can increase or decrease the amplitude component of the third-order distortion generated by a diode or the like to a predetermined value. Can be used. Also, there is no particular limitation on the configuration of the circuit for adjusting the phase of the third-order distortion. For example, various circuit configurations that can advance or delay the phase component of the third-order distortion generated by a diode or the like to a predetermined value. Can be used.

The number of amplifiers for which distortion is compensated by the distortion compensator may be, for example, one.
For example, there may be a plurality. Further, in practical use, for example, an amplifier positioned at the last stage among amplifiers to be compensated for distortion (the amplifier to be compensated for distortion is one).
In this case, it is preferable that the distortion compensation device is provided before the amplifier). However, in the present invention, even when the distortion compensation device is provided, for example, after the amplifier, distortion compensation can be realized. .

Further, in the above-described embodiment, as an example, the case where the distortion compensating apparatus according to the present invention is applied to a portable telephone terminal or the like provided in a communication system has been described. Can be applied to various fields in which compensation is performed. In addition, for example, W-CDMA
In a device such as a mobile phone terminal used for communication in a device where a wide frequency band signal is amplified by an amplifier, it is particularly important to compensate for the third-order distortion generated in the amplifier. It is very effective to apply

[0047]

As described above, according to the distortion compensating apparatus according to the present invention, the distortion compensating apparatus is constituted by a four-terminal power divider, and the first terminal receives a signal input to the amplifier or the like. , A third-order distortion generator of the second terminal and the third terminal generates a third-order distortion having an amplitude and a phase that cancels out the third-order distortion generated by the amplifier, and the fourth terminal has the third terminal of the second terminal and the third terminal. Since the third-order distortion generated by the first-order distortion generator and the input signal are combined and output, the third-order distortion generated by the amplifier is compensated. A distortion compensating device can be configured, and the device can be downsized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration example of a distortion compensation device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a circuit configuration of a distortion compensation device according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a signal processing unit including a distortion compensation device.

[Explanation of symbols]

Q, Q1... 3 dB coupler, T1, P1... Input terminal, T2, P4... Output terminal, T3, T5.
T4, P5-Control voltage terminals, Z1, Z2-
・ Third-order distortion generator, P2 ... 90 ° terminal, P3 ... 0
° terminal, R1 to R6 ··· resistor, C1 to C9 · · capacitor, D1 to D4 · · diode part, N1 · · · input terminal, N2 · · · output terminal, 1, 3, 5, 7, · · · amplifier
2 ・ ・ Distortion compensator 、 4、6 ・ ・ Attenuator,

[Procedure amendment]

[Submission date] April 26, 1999 (1999.4.2
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

In the distortion compensating apparatus shown in FIG. 1, two tertiary distortion generators Z1 and Z2 generate tertiary distortion in response to the input of the basic signal from the input terminal T1.
At dB coupler Q by combining the reflected wave and the fundamental signal of these third order distortion from the output terminal T2.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction contents]

Here, (a) to (f) in FIG.
FIG. 3 conceptually shows an example of a spectrum of a basic signal (basic signal wave) and a third-order distortion when such distortion compensation is performed. The horizontal axis represents frequency, and the vertical axis represents signal strength. Shown , downward spectrum is out of phase
Indicates that In this example, for convenience of explanation, signals of two frequencies within the frequency band of the modulation signal input to the input terminal N1 are shown as basic signals.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Hoshigami 3-14-20 Higashinakano, Nakano-ku, Tokyo International Electric Company (72) Inventor Yasuo Sera 3-14-20 Higashinakano, Nakano-ku, Tokyo International F term (reference) in Electric Co., Ltd. 5J090 AA04 AA41 CA27 CA92 FA08 GN03 GN04 HA19 HA25 HA29 KA12 KA23 MA08 SA13 SA14 TA01 TA03

Claims (1)

[Claims] 1. A distortion compensator for compensating for third-order distortion generated in an amplifier, comprising a power divider having four terminals, a first terminal for inputting a signal input to the amplifier or for inputting a signal output from the amplifier. A second terminal and a third terminal each include a third-order distortion generator that generates a third-order distortion having an amplitude and a phase that cancels out the third-order distortion generated by the amplifier according to the input signal; and the fourth terminal includes the second terminal. And a third-order distortion generator configured to combine the third-order distortion generated by the third-order distortion generator with an input signal and output the combined signal.