JP3367745B2 - Distortion compensator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distortion compensator, and more particularly to a so-called feedforward distortion compensator used for a high frequency amplifier or the like.

[0002]

2. Description of the Related Art A conventional distortion compensator will be described with reference to FIG. IN is an input end, and a high frequency signal is input from the input end IN. The high frequency input signal is supplied to the first power distributor 31.
Is divided into a main signal and an auxiliary signal. Then, the main signal is amplified by the first amplifier 32.

The main signal amplified by the first amplifier 32 and the distortion component generated by the first amplifier 32 are added to the second power distributor 33. This second power distributor 33
Then, a part of the main signal and the distortion component is branched, and the branched component is added to the first power combiner 34.

The main signal and the distortion component that have passed through the second power distributor 33 are added to the second power combiner 36. The second power combiner 36 is connected to the output terminal OUT.

By the way, the main signal and the distortion component, which are partially branched by the second power distributor 33, are included in the first power combiner 3
4, the auxiliary signal distributed by the first power distributor 31 is combined in anti-phase.

Since the same high frequency signal is distributed to the main signal and the auxiliary signal, they cancel each other out in the first power combiner 34, and the distortion component generated in the first amplifier 32 is taken out.

The distortion component extracted by the first power combiner 34 is amplified by the second amplifier 35. Second amplifier 3
The distortion component amplified in 5 is combined in the second power combiner 36 with the main signal amplified in the first amplifier 32 and the distortion component generated in the first amplifier 32 in antiphase.

In the second power combiner 36, the distortion components cancel each other out and the main signal having no distortion component is taken out. This main signal is supplied to the subsequent circuit through the output terminal OUT.

In the conventional distortion compensator having the above structure, the first
It is not always easy to adjust the power combiner 34 so that the main signal and the auxiliary signal cancel each other, and the second power combiner 36 cancel the distortion components.

For example, if the characteristics of the amplifier change due to temperature changes, the characteristics of canceling distortion components and the like deteriorate. In order to improve such a defect, for example, “Technical Research Report of the Institute of Electronics, Information and Communication Engineers (RCS 90-4, vol. 90-4, N.
o. 57, p21-28) ".

This method will be described with reference to FIG. In FIG. 4, the same parts as those in FIG. 3 are designated by the same reference numerals, and the description of the overlapping parts will be omitted.

A first amplifier is provided immediately before or after the first amplifier 32.
The pilot signal generator 47A is provided to add the pilot signal to the high frequency input signal. A pilot signal is detected by a pilot signal detector 46A provided near the output terminal OUT.

Then, the vector adjuster 41B provided before the second amplifier 35 is adjusted so that the detected pilot signal is minimized. This vector adjuster 41
In B, the vector adjuster 41B is set so that the pilot signal detected by the pilot signal detector 46A is minimized.
The amplitude and phase of the signal passing through are adjusted.

With this configuration, the distortion component is prevented from being output from the output terminal OUT. Further, a pilot signal generator 47B for generating a second pilot signal is provided at the input end IN, and this pilot signal is added to the high frequency input signal inputted from the input end IN. Then, the pilot signal detector 46B provided at the subsequent stage of the first power combiner 34 detects this pilot signal. Then, the vector adjuster 41A provided before the first amplifier 32 is adjusted so that the detected pilot signal is minimized.

The vector adjuster 41A adjusts the amplitude and phase of the signal passing through the vector adjuster 41A so that the pilot signal detected by the pilot signal detector 46B is minimized. With this configuration, only the distortion component is added to the second amplifier 35.

[0016]

In the distortion compensator having the above-described conventional structure, the characteristic of canceling the distortion component is changed by the change of the characteristics of the amplifier due to the temperature change and the like. There is a way to do it. However, when the pilot signal generator is used in or near the band, a high frequency oscillator must be prepared to generate the pilot signal. The high frequency oscillator has a complicated structure and configuration.

Although a low-frequency oscillator can be used, a multiplier is required, which also complicates the structure and configuration. Further, when the pilot signal is arranged near the lower end or near the upper end of the band, the amount of distortion compensation sharply deteriorates at the band end distant from the pilot signal. It is possible to avoid this and perform distortion compensation in a wide band by using two or more complex pilot signals in total at both ends of the band, but pilot signal generation for each pilot signal is possible. Prepare a detector and pilot signal detector,
Since each of the detected signals must be minimized by the vector adjuster, the structure and configuration of the distortion compensator become more and more complicated.

The present invention solves the above-mentioned drawbacks and uses a plurality of pilot signal generators without using a pilot signal generator whose structure and configuration are complicated, and even when distortion compensation is performed in a wide band. An object of the present invention is to provide a distortion compensator that does not require the above.

[0019]

According to the present invention, there is provided a first power distributor for distributing an input signal into a main signal and an auxiliary signal, and the main signal distributed by the first power distributor is modulated. A modulator for generating a sideband signal, a first vector adjuster for adjusting the amplitude and phase of a main signal modulated by the modulator, a first amplifier for amplifying the main signal, and a first Second power distributor for distributing the main signal amplified by the amplifier, and one signal distributed by the second power distributor and the auxiliary signal distributed by the first power distributor. A first power combiner that does, and a main signal detector that detects a main signal from the signal power-combined by the first power combiner,
A second vector adjuster connected to the first power combiner to adjust the amplitude and phase of the signal combined by the first power combiner, and the signal transmitted by the second vector adjuster. A second amplifier for amplifying the signal, a second power combiner for combining the other signal distributed by the second power distributor and the signal amplified by the second amplifier, and the second power combiner Connected to the power combiner for transmitting an output signal and detecting a sideband signal, the sideband signal detector interposed between the main signal detector and the first vector adjuster, and the main signal Of the first controller to control the first vector adjuster so that the value of the main signal detected by the detector is minimized, the sideband signal detector and the second vector adjuster The value of the sideband signal interposed by the sideband signal detector is minimized. Providing a distortion compensator characterized by comprising a second control unit for controlling the urchin said second vector adjuster.

Further, according to the present invention, there is provided a pilot signal generator for generating a pilot signal, a first power distributor for distributing an input signal into a main signal and an auxiliary signal, and the first power distributor. A modulator that modulates the main signal to generate a sideband signal, a first vector adjuster that adjusts the amplitude and phase of the main signal modulated by this modulator, and a first vector amplifier that amplifies this main signal. An amplifier, a second power distributor for distributing the main signal amplified by the first amplifier, one signal distributed by the second power distributor, and the second power distributor for distribution by the first power distributor. Connected to the first power combiner, a pilot signal detector for detecting a pilot signal from the signal power-combined by the first power combiner, , The signal synthesized by the first power combiner Of the second vector adjuster for adjusting the amplitude and phase of the second amplifier, the second amplifier for amplifying the signal transmitted by the second vector adjuster, and the other of the second power distributor for distributing the signal. A second power combiner for combining the signal and the signal amplified by the second amplifier, and a sideband for connecting to the second power combiner to output an output signal and detecting a sideband signal. A signal detector, interposed between the pilot signal detector and the first vector adjuster,
A first control unit that controls the first vector adjuster so that the value of the pilot signal detected by the pilot signal detector is minimized, the sideband signal detector, and the second vector adjustment And a second controller for controlling the second vector adjuster so that the value of the sideband signal detected by the sideband signal detector is minimized. Distortion compensator characterized by the above.

[0021]

According to the distortion compensator of the present invention having the above structure, the modulator is used instead of the distortion compensation using the pilot signal. Therefore, compensation is performed by detecting and controlling the sideband signal generated by modulating the main signal with the modulator.

Therefore, distortion compensation is facilitated without the need for a high-frequency oscillator used to generate a pilot signal or a multiplier when a low-frequency oscillator is used. Furthermore, when performing wideband distortion compensation,
Conventionally, a plurality of pilot signal generators are required, but if a modulator is used, distortion compensation can be easily performed because the upper sideband signal and the lower sideband signal generated by modulating the main signal are used.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. IN is an input end, and a high frequency input signal is input from this input end IN. The high frequency input signal is divided into a main signal and an auxiliary signal by the first power divider 11. The main signal passes through the first vector adjuster 21A and then the first amplifier 1
It is amplified by 2.

The modulator 22 modulates the main signal in front of the first amplifier 12 to generate an upper sideband signal and a lower sideband signal in the main signal. The main signal amplified by the first amplifier 12 and the distortion component generated by the first amplifier 12 are added to the second power distributor 13 together with the upper sideband signal and the lower sideband signal. Then, the second power distributor 13 distributes part of the main signal, the distortion component, the upper sideband signal, and the lower sideband signal, and the first power combiner 14
Added to.

The main signal, the distortion component, the upper sideband signal and the lower sideband signal that have passed through the second power distributor 13 are added to the second power combiner 16. The second
The power combiner 16 of is connected to the output terminal OUT.

By the way, the main signal, the distortion component, the upper sideband signal and the lower sideband signal, which are partly distributed by the second power distributor 13, are processed by the first power combiner 14 to generate the first power. The auxiliary signal distributed by the distributor 11 is combined in anti-phase.

Since the same high frequency input signal is distributed to the main signal and the auxiliary signal, the first power combiner 1
In 4, the main signal and the auxiliary signal cancel each other, and the distortion component generated in the first amplifier 12, the upper sideband signal and the lower sideband signal are extracted.

A main signal detector 23 is connected to the output side of the first power combiner 14. The detected signal is the first
Is input to the control unit 25A. This first control unit 25A
Controls the first vector adjuster 21A so that the input detection signal is minimized in order to stably extract the distortion component, the upper sideband signal and the lower sideband signal.

The distortion component, the upper sideband signal, and the lower sideband signal extracted by the first power combiner 14 are amplified by the second amplifier 15 via the second vector adjuster 21B. .

The distortion component, the upper sideband signal, and the lower sideband signal amplified by the second amplifier 15 are supplied to the second power combiner 16 and the main signal and the first side signal amplified by the first amplifier 12 are supplied. The distortion component generated in the amplifier 12 of No. 1 and the upper sideband signal and the lower sideband signal are combined in opposite phase.

In the second power combiner 16, the distortion component added from the second power divider 13 and the distortion component added from the second amplifier 15 have the same amplitude and opposite phases. Both distortion components cancel each other and no distortion component remains.

Therefore, since the distortion component and the components of the upper sideband signal and the lower sideband signal are eliminated, and the modulated main signal is demodulated, the demodulated main signal having no distortion component is taken out.

A sideband detector 2 for detecting an upper sideband signal and a lower sideband signal at the output side of the second power combiner 16.
4 is connected. The detected signal is input to the second controller 25B. The second control unit 25B stably extracts the demodulated main signal having a small distortion component in a wide band, so that the input detection signals of the upper sideband signal and the lower sideband signal are simultaneously minimized. And controls the second vector adjuster 21B.

The vector adjuster 21B has a distortion component passing therethrough and an amplitude of the upper sideband signal and the lower sideband signal,
The phase is adjusted, and the amplitude and phase of the upper sideband signal and the lower sideband signal are adjusted so that the upper sideband signal and the lower sideband signal detected by the sideband signal detector 24 are minimized. It is controlled by the control unit 25B.

By the control of the above-mentioned vector adjuster 21B, the main signal with less distortion component is output from the output terminal OUT and supplied to the circuit in the subsequent stage. In FIG. 1, the modulator 2
2 to the first power distributor 11 and the first vector adjuster 21.
Although it was placed between A, the first power distributor 11 and the second
The same effect can be obtained wherever the modulator 22 is arranged, including before and after the first amplifier 12 or including the modulator 22 in the first power amplifier 12 as long as it is between the power dividers 13. .

In the above embodiment, the method of detecting the upper sideband signal and the lower sideband signal generated by modulating the main signal and controlling the distortion correction in a wide band stably was described. If it is not necessary to increase the width, the sideband signal detector 24 that detects only one of the upper sideband signal and the lower sideband signal can be used. In this case, the configurations and structures of the sideband signal detector 24 and the control unit 25B become easier.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In the embodiment shown in FIG. 2, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description will be focused on the parts different from the first embodiment.

A pilot signal generator 27 for generating a pilot signal is provided near the input terminal IN. A part of the high frequency input signal to which the pilot signal is added is branched by the first power distributor 11.

The input signal and pilot signal to which the first power distributor 11 is added are added to the first amplifier 12 via the first vector adjuster 21A. In addition, the second vector adjuster 21B and the first power combiner 14
A pilot signal detector 26 is connected between and.

With the above-mentioned configuration, the pilot signal is detected by the pilot signal detector 26, and the first vector adjuster 21A is adjusted via the first controller 25A so that the pilot signal is minimized.

As a result, in the first power combiner 14,
The distortion component generated in the first amplifier 12 and the upper sideband signal and the lower sideband signal generated in the main signal by modulating the main signal by the modulator 22 are extracted.

[0042]

According to the present invention, since the modulator is used, the distortion compensator can be provided with a simple structure and configuration. In addition, distortion compensation can be performed in a wide band by a simple method.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a distortion compensator according to the present invention.

FIG. 2 is a circuit configuration diagram showing another embodiment of the distortion compensator according to the present invention.

FIG. 3 is a circuit configuration diagram illustrating a conventional distortion compensator.

FIG. 4 is a circuit configuration diagram illustrating a conventional distortion compensator.

[Explanation of symbols]

IN: input end OUT ... Output end 11 ... First power distributor 12 ... First amplifier 13 ... Second power distributor 14 ... First power combiner 15 ... Second amplifier 16 ... Second power combiner 21A, 21B ... Vector adjuster 22 ... Modulator 23 ... Main signal detector 24 ... Sideband signal detector 25A, B ... Control unit 26 ... Pilot signal detector 27 ... Pilot signal generator

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H03F 1/32

Claims (6)

(57) [Claims] 1. A first power distributor for distributing an input signal into a main signal and an auxiliary signal, and a modulation for modulating the main signal distributed by the first power distributor to generate a sideband signal. A vessel,
A first vector adjuster for adjusting the amplitude and phase of a main signal modulated by this modulator, a first amplifier for amplifying this main signal, and a distribution of the main signal amplified by this first amplifier A second power distributor, a first power combiner for combining one of the signals distributed by the second power distributor and the auxiliary signal distributed by the first power distributor, and the first power combiner A main signal detector for detecting a main signal from a signal power-combined by one power combiner, and an amplitude and a phase of the signal combined by the first power combiner, the main signal detector being connected to the first power combiner. A second vector adjuster for adjusting the signal, a second amplifier for amplifying the signal sent by the second vector adjuster, the other signal distributed by the second power distributor, and the second A second power combiner for combining the signal amplified by the second amplifier, and A sideband signal detector that is connected to a second power combiner to output an output signal and detects a sideband signal, is interposed between the main signal detector and the first vector adjuster, and A first controller that controls the first vector adjuster so that the value of the main signal detected by the main signal detector is minimized, the sideband signal detector, and the second vector adjuster. And a second control unit for controlling the second vector adjuster so that the value of the sideband signal detected by the sideband signal detector is minimized. Distortion compensator characterized by. 2. A pilot signal generator for generating a pilot signal, a first power distributor for distributing an input signal into a main signal and an auxiliary signal, and a main signal distributed by the first power distributor. A modulator that modulates and produces a sideband signal;
A first vector adjuster for adjusting the amplitude and phase of a main signal modulated by this modulator, a first amplifier for amplifying this main signal, and a distribution of the main signal amplified by this first amplifier A second power distributor, a first power combiner for combining one of the signals distributed by the second power distributor and the auxiliary signal distributed by the first power distributor, and the first power combiner A pilot signal detector that detects a pilot signal from a signal power-combined by one power combiner, and the amplitude and phase of the signal combined by the first power combiner, connected to the first power combiner A second vector adjuster for adjusting the signal, a second amplifier for amplifying the signal sent by the second vector adjuster, the other signal distributed by the second power distributor, and the second The second that combines the signal amplified by the second amplifier Of a force combiner, a sideband signal detector connected to the second power combiner to output an output signal and detect a sideband signal, the pilot signal detector and the first vector adjuster. A first control unit interposed between and controlling the first vector adjuster so that the value of the pilot signal detected by the pilot signal detector is minimized; the sideband signal detector; A second control that is interposed between the second vector adjuster and controls the second vector adjuster so that the value of the sideband signal detected by the sideband signal detector is minimized. And a distortion compensator. 3. The main power signal distributed by the first power distributor and the sideband signal generated by modulating the main signal by the modulator, and the first power distributor. The distortion compensator according to claim 1 or 2, wherein a part of the distortion component generated by being amplified by the amplifier is distributed. 4. The modulator according to claim 1, wherein the modulator generates sideband signals near upper and lower ends of a band of the main signal distributed by the first power distributor. Distortion compensator. 5. The first power combiner distributes a main signal including sideband signals and distortion components distributed by the second power distributor, and an auxiliary signal distributed by the first power distributor. 3. The sideband signal generated by modulating the main signal by the modulator and the distortion component generated by the first amplifier are extracted by power combining with the above, and the distortion component is extracted. Distortion compensator. 6. The second power combiner outputs a main signal including a sideband signal amplified by the first amplifier and a distortion component generated by the first amplifier to the second amplifier. Power combining with the amplified sideband signal and distortion component, and removing the sideband signal generated by modulating the main signal by the modulator and the distortion component generated by the first amplifier. The distortion compensator according to claim 1 or 2.