JPH09284059A - Feed forward amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a feed forward amplifier whereby the output signal of a level detecting circuit is made to be a min. value at high speed by executing adjustment so as to permit a signal which is injected by controlling a vector adjusting equipment to be the min. value. SOLUTION: The output signal of a main amplifier 4 is distributed to a signal route (c) and the signal route (d) by a distributor 21 and synthesized by a synthesizer 6. The distortion component of the main amplifier 4, which is taken-out by the synthesizer 9 is canceled by permitting amplitude and a phase to be the same amplitude and the opposite phase in the signal route (c) and the signal route (d) so that the output signal with no distortion from an output terminal is obtained. The vector adjusting equipment 10 is controlled by a control circuit 17 so as to permit a pilot signal injected by a pilot signal injector 3 to be the min. one in the distributor 19 in order to obtain the same amplitude and the opposite phase in the signal route (c) and the signal route (d). Thus, a distortion removing loop is controlled at high speed and distortion occurrence is restricted to the min.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feedforward amplifier, and more particularly to a feedforward amplifier that needs to be controlled at high speed.

[0002]

2. Description of the Related Art As a conventional feedforward amplifier, there is an invention of a feedforward interference circuit described in, for example, Japanese Patent Laid-Open No. 5-90843. The invention described in the above publication is designed to inject a pilot signal before the distortion removal loop and remove the distortion for the purpose of enabling pilot detection with high sensitivity and being hardly affected by interference such as noise. After the loop, automatic control was performed so that the pilot signal component was minimized.

FIG. 12 is a block diagram showing a feedforward amplifier in a conventional example, which is described in the above publication. The input signal input from the input terminal 123 is input to the power distributor 124. Also, f ₁
To f _n, one low-frequency signal f _i (i
, 1, 2, ..., N), the carrier wave output from the local oscillator 143 is amplitude-modulated by the modulator 144. The modulated output signal is taken out as a pilot signal through the bandpass filter 145 to obtain the pilot injection circuit 13
6, and the power distributor 124 divides the power into two paths 125 and 126. The path 125 includes a variable attenuator 129, a variable phase shifter 130, and an amplifier 131. Route 126 is
The delay line 132 and the phase inversion circuit 133 are provided. The power combiner 128 combines the output signals of the paths 125 and 126. A pilot signal is extracted from the combined output signal by the pilot extraction circuit 137 and output from the output terminal 127. Further, the extracted pilot signal is synchronously restored by the output signal of the local oscillator 143 by the demodulator 148 through the bandpass filter 147, and the lowpass filter 149.
The low frequency signal f _i is taken out with. Obtained low frequency signal f _i
Level is detected by the level detection circuit 138. The detected output signal is supplied to the control circuit 139 as the detection level of the pilot signal. The control circuit 139 controls the variable attenuator 1 so that the detection level of the pilot signal is minimized.
29 and the variable phase shifter 130.

[0004]

In the conventional feedforward amplifier, there is a problem that it takes time to converge to the optimum point when the distortion elimination loop formed by the paths 125 and 126 is automatically controlled. is there. The reason is that the variable attenuator 129 and the variable phase shifter 130 are controlled in order to minimize the detection level of the level detection circuit 138, but if the output signal of the level detection circuit 138 is observed, the variable attenuator 129 is controlled. Output signal and variable phase shifter 130
It is not possible to know which of the output signals of the above is shifted and how much, and the variable attenuator 129 and the variable phase shifter 130 are changed to some extent by using the Newton method or the like, and the operation of viewing the output signal of the level detection circuit 138 is repeated. By doing so, the minimum point must be sought. Therefore, the time until the detection level reaches the minimum value also differs depending on the degree of deviation between the variable attenuator 129 and the variable phaser 130.

An object of the present invention is to provide a feedforward amplifier capable of minimizing the output signal of the level detection circuit at a high speed regardless of the deviation of the variable attenuator and the variable phase shifter.

[0006]

A feedforward amplifier of the present invention is a feedforward amplifier which supplies a pilot signal to a distortion elimination loop to perform automatic control for minimizing the detection level of the pilot signal. And a first dividing means (20) for dividing the pilot signal, which is an output signal of the pilot signal generating means (12), into a first signal and a second signal. A second distribution means (18) for dividing an input signal input from the input terminal (1) into a third signal and a fourth signal, and the second distribution means (18). A first vector adjusting means (2) for adjusting the amplitude and the phase by inputting the third signal;
First synthesizing means for synthesizing the first signal and the third signal whose amplitude and phase are adjusted by the first vector adjusting means (2), which are distributed by the distributing means (20) (3), a main amplification means (4) for amplifying the output signal of the first combining means (3), and the second signal distributed by the first distribution means (20) Phase shifting means (13) for varying the phase, first delay means (8) for delaying the fourth signal distributed by the second distributing means (18), and the main amplifying means (4). Third dividing means (21) for dividing the output signal of the second signal into a fifth signal and a sixth signal.
A second delay means (5) for delaying the fifth signal distributed by the third distribution means (21), and a sixth delay means (5) distributed by the third distribution means (21). Second synthesizing means (9) for synthesizing the signal and the signal delayed by the first delay means (8), and the second synthesizing means (9)
Second vector adjusting means (10) for inputting the output signal of the second vector adjusting the amplitude and phase, and an auxiliary amplifying means (11) for amplifying the output signal of the second vector adjusting means (10).
A third synthesizing means (6) for synthesizing the signal delayed by the second delaying means (5) and the output signal of the auxiliary amplifying means (11), and the third synthesizing means (6). A second dividing means (19) for dividing the output signal of the second signal into a seventh signal and an eighth signal, the seventh signal distributed by the fourth dividing means (19), and the phase shift Multiplying means (14) for receiving the output signal of the means (13) for multiplication, level detecting means (16) for receiving the output signal of the multiplying means (14) and extracting a DC component, and the level detecting means The output signal of the means (16) is input to the first vector adjusting means (2), the second vector adjusting means (10) and the phase shifting means (1).
3) has a control means (17) and an output terminal (7) for outputting the eighth signal distributed by the fourth distribution means (19).

In the feedforward amplifier of the present invention, the input signal input from the input terminal (1) is converted into the third signal and the fourth signal by the second distributing means (18). The third signal is divided into two, and the fourth signal is input to the second combining means (9) via the first delay means (8) as a signal path a. The sixth vector adjusting means (2), the first synthesizing means (3) and the main amplifying means (4) are divided into two by the third dividing means (21) and the sixth vector is adjusted. Assuming that the path input to the second synthesizing means (9) as a signal is the signal path b, the signal path a and the signal path b have the same amplitude and opposite phase, and the main amplifying means (4) A distortion extraction loop for extracting a distortion component as an output signal of the second synthesizing means (9); The output signal of the wide section (4) comprises a third distribution means (21) two are partitioned between the fifth signal and the signal of the sixth, the said signal of said 5 second
The third synthesizing means (6) via the delay means (5)
The sixth signal is input to the second synthesizing means (9), and the main amplifying means (4) extracted by the second synthesizing means (9) is used as a signal path c input to the second synthesizing means (9). If the path through which the distortion component of (1) is input to the third combining means (6) via the second vector adjusting means (10) and the auxiliary amplifying means (11) is a signal path d, The signal path c and the signal path d have the same amplitude and opposite phase, and the distortion component of the main amplification means (4) extracted by the distortion extraction loop is combined by the third combining means (6). And a distortion removing loop that outputs the eighth signal out of the two distributed by the fourth distributing means (19) as a distortion-free output signal from the output terminal (7).

Further, when the signal path c and the signal path d have the same amplitude and opposite phase, the second vector adjusting means (10) is controlled by the control means (17) to The first signal injected into the first synthesizing means (3) is adjusted by the fourth distributing means (19) so as to have a minimum value.

With this configuration, synchronous detection is used as a detection method for detecting the pilot signal, and at this time, the phase of the output signal of the local oscillator for synchronous detection is variably controlled, The amplitude and phase of the pilot signal remaining in the distortion removal loop can be known by examining the change in the detection output signal of the level detecting means with respect to the variable amount of phase. Therefore, it is possible to calculate how much the pilot signal remaining in the distortion elimination loop deviates from the optimum value of the vector adjuster, so that the distortion elimination loop can be controlled at high speed.

[0010]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a feedforward amplifier according to an embodiment of the present invention.

First, the configuration of FIG. 1 will be described. The feedforward amplifier shown in FIG. 1 is divided by a pilot signal generator 12 that generates a pilot signal, a divider 20 that divides a pilot signal that is an output signal of the pilot signal generator 12 into two, and a divider 20. A pilot signal injector 3 for injecting one of the signals into the main amplifier 4,
The phase shifter 13 that changes the other phase of the signal distributed by the distributor 20, the distributor 18 that divides the signal input from the input terminal 1 into two, and the amplitude of one of the signals distributed by the distributor 18. And a vector adjuster 2 for adjusting the phase and inputting it to the pilot signal injector 3, a delay device 8 for delaying the other of the signals distributed by the distributor 18, and a main unit for amplifying the output signal of the pilot signal injector 3. Amplifier 4
And a divider 21 for dividing the output signal of the main amplifier 4 into two,
The delay unit 5 that delays one of the signals distributed by the distributor 21, and the combiner 9 that combines the other of the signals distributed by the distributor 21 and the signal delayed by the delay unit 8
A vector adjuster 10 for adjusting the amplitude and phase of the output signal of the combiner 9 and inputting it to the auxiliary amplifier 11, and an auxiliary amplifier 11 for amplifying the output signal of the vector adjuster 10.
A combiner 6 for combining the signal delayed by the delay device 5 and the output signal of the auxiliary amplifier 11, a distributor 19 for extracting a part of the output signal of the combiner 6, and an output signal extracted by the distributor 19. Of the output signal of the phase shifter 13, a level detector 16 for extracting the DC component of the output signal of the multiplier 14, and a vector by inputting the output signal of the level detector 16 The control circuit 17 controls the regulators 2 and 10 and the phase shifter 13.

The signal input from the input terminal 1 is divided into two by the divider 18, and one of them is adjusted in amplitude and phase by the vector adjuster 2.

The pilot signal generated by the pilot signal generator 12 is divided into two by the distributor 20, and one of them is injected into the output signal of the vector adjuster 2 by the pilot signal injector 3. The output signal of the vector adjuster 2 into which the pilot signal is injected is amplified by the main amplifier 4, divided into two by the divider 21, and one of them is input to the combiner 9.

The other output signal of the distributor 18 is the delay device 8
After being delayed by, it is input to the combiner 9 and combined with one output signal of the distributor 21. The other output signal of the distributor 21 is delayed by the delay device 5 and then input to the combiner 6.

The output signal of the combiner 9 is the vector adjuster 1
The amplitude and the phase are adjusted by 0 and amplified by the auxiliary amplifier 11. The output signal of the auxiliary amplifier 11 is input to the combiner 6 and combined with the signal delayed by the delay device 5. The output signal of the combiner 6 in which the distortion components have been canceled is divided into two by the distributor 19, one of which is output from the output terminal 7 and the other of which is input to the multiplier 14.

The other output signal of the distributor 20 is the phase shifter 1
After the phase is adjusted in 3, the signal is input to the multiplier 14 and multiplied by the output signal of the distributor 19. The output signal of the multiplier 14 has its direct current component extracted by the level detector 16 and input to the control circuit 17.

Next, the operation of FIG. 1 will be described. Input terminal 1
The signal input from is distributed by the distributor 18 to the signal path a and the signal path b, and is combined by the combiner 9. At this time, by setting the signal path a and the signal path b to have the same amplitude and opposite phase, only the distortion component of the main amplifier 4 is extracted from the output signal of the combiner 9. Here, the signal path a
A loop formed by and the signal path b is called a distortion extraction loop.

The output signal of the main amplifier 4 is supplied to the distributor 2
1 is distributed to the signal path c and the signal path d, and the combiner 6
Synthesized by At this time, by setting the signal path c and the signal path d to have the same amplitude and opposite phase, the distortion component of the main amplifier 4 extracted by the combiner 9 can be canceled by the combiner 6, and the output terminal 7 outputs nothing. A distorted output signal can be obtained. Here, the loop formed by the signal path c and the signal path d is called a distortion removal loop.

In order to make the signal path c and the signal path d have the same amplitude and opposite phase, the pilot signal injected by the pilot signal injector 3 is minimized by the distributor 19.
The vector adjuster 10 may be controlled by the control circuit 17.

FIG. 2 is a vector diagram showing the signal route in FIG. 1, FIG. 2 (a) is a vector diagram showing the signal route c, and FIG. 2 (b) is a vector diagram showing the signal route d. . FIG. 3 is a vector diagram showing the pilot signal in a state before the distortion elimination loop is optimized, and the signal path c and the signal path d are also overlaid. FIG. 4 is a diagram showing the output signal of the level detector when the operation of the auxiliary amplifier is stopped. FIG. 5 is a diagram showing an output signal of the level detector when the auxiliary amplifier is operated. FIG. 6 is a vector diagram showing the states of FIGS. 4 and 5.

In FIG. 2, signal path c and signal path d
The signal component vector 50 and the distortion component vector 5 of the signal path c when the distortion removal loop constituted by
1, the distortion component vector 54 of the signal path d, the pilot signal component vector 52 of the signal path c, and the pilot signal component vector 53 of the signal path d are shown. At this time,
The vector 52 and the vector 53 have the same amplitude and the opposite phase, and the vector 51 and the vector 54 have the same amplitude and the opposite phase. When the distortion elimination loop is optimum, the pilot signal component extracted from the distributor 19 is 0.
It is. Here, let us consider a state before the distortion elimination loop is optimized, such as immediately after the power is turned on.

In FIG. 3, a vector 52 is a pilot signal component of the signal path c, and a vector 53 is a pilot signal component of the signal path d when the distortion elimination loop is optimum. Immediately after the power is turned on and before the distortion removal loop is optimized, the pilot signal component of the signal path d is usually a vector 53 having an optimum value like the vector 55.
It is out of alignment. Therefore, the pilot signal component extracted from the distributor 19 becomes like the vector 56.

In the state of FIG. 3, first, the operation of the auxiliary amplifier 11 is stopped, and the phase of the signal input to the multiplier 14 is changed by the phase shifter 13 from 0 ° to 360 °. , An output signal as shown in FIG. 4 is obtained. Here, the phase shift amount of the phase shifter 13 when the output signal of the level detector 16 becomes maximum is set as the phase shift amount θ1, and the amplitude of the level detector 16 is set as the amplitude A1.

Next, when the auxiliary amplifier 11 is operated and the phase of the signal input to the multiplier 14 is similarly varied by the phase shifter 13 from 0 ° to 360 °, the level detector 16
From, an output signal as shown in FIG. 5 is obtained. Here, the phase shift amount when the output signal of the level detector 16 becomes maximum is the phase shift amount θ2, and the amplitude of the level detector 16 is the amplitude A.
Let it be 2.

The above results are shown in FIG. The amplitude A1 indicates the amplitude component of the vector 52, and the amplitude A2 is the composite vector 5
6 shows the amplitude component of 6. The difference θ3 between the phase shift amount θ2 and the phase shift amount θ1 indicates the phase shift angle between the vector 52 and the combined vector 56. From these facts, by using the cosine theorem for the vector 52 which is the pilot signal component of the signal path c and the combined vector 56 of the signal paths c and d, the vector 55 of the signal path d before the distortion elimination loop is optimized. Can be asked. Further, the optimum vector 53, which is the pilot signal component of the signal path d when the distortion removal loop is optimum, has the same amplitude and opposite phase to the vector 52, and therefore can be easily obtained. Therefore, the difference in the amplitude and the phase between the vector 53 and the vector 55 can be obtained, so that the distortion removing loop can be optimized by controlling the vector adjuster 10 by the amount of this difference.

[0027]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 7 is a block diagram showing an embodiment of the feedforward amplifier of the present invention.

The configuration of FIG. 7 will be described. The signal input from the input terminal 1 is split into two by the 3 dB hybrid 43, and one of them is varied in amplitude and phase by the variable attenuator 30 and the variable phase shifter 31.

The pilot signal generated by the pilot signal generator 12 is divided into two by the 3 dB hybrid 36, and then the directional coupler 37 is used by the directional coupler 37.
1 is injected into the output signal. The signal into which the pilot signal is injected is amplified by the main amplifier 4, part of the signal is extracted by the directional coupler 38, and the signal is input to the coupling terminal of the directional coupler 39.

The other output signal of the 3 dB hybrid 43, after being delayed by the semi-rigid coaxial cable 33,
The signal is input to the directional coupler 39 and combined with the output signal of the directional coupler 38.

The remaining output signal of the directional coupler 38 is input to the directional coupler 40 after being delayed by the semi-rigid coaxial cable 32.

The output signal of the directional coupler 39 has its amplitude and phase varied by the variable attenuator 34 and the variable phase shifter 35, and is amplified by the auxiliary amplifier 11. The output signal of the auxiliary amplifier 11 is input to the coupling terminal of the directional coupler 40 and combined with the signal delayed by the semi-rigid coaxial cable 32. A part of the output signal of the directional coupler 40 is taken out by the directional coupler 41, and the rest is output from the output terminal 7. The output signal extracted by the directional coupler 41 is input to the multiplier 44.

The other output signal of the 3 dB hybrid 36 has its phase changed by the variable phase shifter 45, and then the multiplier 4
4 and is multiplied by the output signal of the directional coupler 41. A DC component of the output signal of the multiplier 44 is extracted by the low-pass filter 42 and is input to the control circuit 17. The control circuit 17 includes a variable attenuator 30, a variable phase shifter 3
1. The variable attenuator 34, the variable phase shifter 35, and the variable phase shifter 45 are controlled.

Next, the operation of FIG. 7 will be described. Input terminal 1
The signal input from is distributed to the signal path a and the signal path b by the 3 dB hybrid 43, and the directional coupler 39
Synthesized by At this time, by setting the signal path a and the signal path b to have the same amplitude and opposite phase, only the distortion component of the main amplifier 4 is extracted from the output signal of the directional coupler 39. Here, the loop formed by the signal path a and the signal path b is called a distortion extraction loop.

The output signal of the main amplifier 4 is distributed to the signal path c and the signal path d by the directional coupler 38 and is combined by the directional coupler 40. At this time, by setting the signal path c and the signal path d to have the same amplitude and opposite phase, the distortion component of the main amplifier 4 extracted by the directional coupler 39 can be canceled by the directional coupler 40, and the output An undistorted output signal can be obtained from the terminal 7. Here, the loop formed by the signal path c and the signal path d is called a distortion removal loop.

In order to make the signal path c and the signal path d have the same amplitude and opposite phase, the pilot signal injected by the directional coupler 37 is minimized by the directional coupler 41.
The variable attenuator 34 and the variable phase shifter 35 may be controlled by the control circuit 17. Now, let us consider the state before the distortion elimination loop is optimized, such as immediately after the power is turned on.

FIG. 8 is a vector diagram showing a pilot signal in a state before the distortion elimination loop is optimized, and the signal path c and the signal path d are also shown in an overlapping manner. FIG. 9 is a diagram showing an output signal of the low-pass filter when the operation of the auxiliary amplifier is stopped. FIG. 10 is a diagram showing an output signal of the low-pass filter when the auxiliary amplifier is operated. FIG. 11 is a vector diagram showing the states of FIGS. 9 and 10.

In FIG. 8, vector 52 is signal path c.
Vector 53 is a pilot signal component of the signal path d when the distortion removal loop is optimum. Immediately after the power is turned on and before the distortion elimination loop is optimized, the pilot signal component of the signal path d is usually deviated from the optimum value, so that the directional coupler 41 outputs the combined vector 56 of the signal paths c and d. Is output.

In the state of FIG. 8, first, the operation of the auxiliary amplifier 11 is stopped, and the multiplier 4 is operated by the variable phase shifter 45.
When the phase of the signal input to 4 is changed from 0 ° to 360 °, an output signal as shown in FIG. 9 is obtained from the low pass filter 42. Here, the phase shift amount of the variable phase shifter 45 when the output signal of the low pass filter 42 becomes maximum is 2
The amplitude of the low-pass filter 42 is set to 00 °.

[0041]

[Outside 1] (A is a constant).

Next, when the auxiliary amplifier 11 is operated and the phase of the signal input to the multiplier 44 is changed from 0 ° to 360 ° by the variable phase shifter 45 in the same manner, the low-pass filter 42 changes the phase as shown in FIG. An output signal as shown is obtained. Here, the phase shift amount when the output signal of the low-pass filter 42 becomes maximum is 170 °, and the low-pass filter 4
The amplitude of 2 is (2 · a).

The above results are shown in FIG. From these, the vector 52 of the signal path c and the signal paths c and d
By using the cosine theorem for the composite vector 56 of
Obtaining the vector 55 of the signal path d is as follows.

[0044]

[Equation 1] here,

[0045]

[Equation 2] A2 = 2 · a (3) θ3 = (200 ° −170 °) = 30 ° (4) Therefore, A3 = a.

In addition,

[0047]

(Equation 3) Therefore, θ4 = 60 °.

The optimum vector 53 of the signal path d is
Since the vector 52 has the same amplitude and opposite phase,
It looks like this:

[0049]

(Equation 4) θ5 = 180 ° − (θ3 + θ4) = 90 ° (7) Therefore, the difference in amplitude and phase between the vector 53 and the vector 55 is obtained as follows.

[0050]

(Equation 5) Shift of variable phase shifter 35 = 90 ° (9) Variable attenuator 34 and variable phase shifter 3 by the amount of this phase difference
If 5 is controlled, the distortion elimination loop can be optimized.

[0051]

The effect of the present invention is that the distortion elimination loop can be controlled at high speed. This makes it possible to minimize the occurrence of distortion.

The reason is that the synchronous detection is used as the detection method for detecting the pilot signal, and at this time, the phase of the output signal of the local oscillator for the synchronous detection is variably controlled so as to correspond to the variable amount of the phase. By examining the change in the detection output signal of the level detecting means, the amplitude and phase of the pilot signal remaining in the distortion removal loop can be known. Therefore, the deviation of the pilot signal remaining in the distortion removal loop from the optimum value of the vector adjuster can be calculated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a feedforward amplifier according to an embodiment of the present invention.

FIG. 2 is a vector diagram of a signal path in FIG.

FIG. 3 is a vector diagram showing a pilot signal before the distortion elimination loop is optimized.

FIG. 4 is a diagram showing an output signal of the level detector when the operation of the auxiliary amplifier is stopped.

FIG. 5 is a diagram showing an output signal of a level detector when an auxiliary amplifier is operated.

FIG. 6 is a vector diagram showing the states of FIGS. 4 and 5;

FIG. 7 is a block diagram showing an embodiment of a feedforward amplifier of the present invention.

FIG. 8 is a vector diagram showing a pilot signal before the distortion elimination loop is optimized.

FIG. 9 is a diagram showing an output signal of the low-pass filter when the operation of the auxiliary amplifier is stopped.

FIG. 10 is a diagram showing an output signal of a low-pass filter when an auxiliary amplifier is operated.

FIG. 11 is a vector diagram showing the states of FIGS. 9 and 10.

FIG. 12 is a block diagram showing a feedforward amplifier in a conventional example.

[Explanation of symbols] 1 input terminal 2,10 vector adjuster 3 pilot signal injector 4 main amplifier 5,8 delay device 6,9 combiner 7 output terminal 11 auxiliary amplifier 12 pilot signal generator 13 phase shifter 14 multiplier 16 Level detector 17 Control circuit 18, 19, 20, 21 Distributor 30, 34 Variable attenuator 31, 35, 45 Variable phase shifter 32, 33 Semi-rigid coaxial cable 36, 43 3dB hybrid 37, 38, 39, 40, 41 directional coupler 42 low-pass filter 44 multiplier 50, 51, 52, 53, 54, 55 vector 56 composite vector 123 input terminal 124 power distributor 125, 126 path 127 output terminal 128 power combiner 129 variable attenuator 130 variable Phase shifter 131 Amplifier 132 Delay line 133 Phase inversion circuit 136 Pilot injection circuit 137 Pilot extraction circuit 138 Level detection circuit 139 Control circuit 141 Pilot signal generator 142 Frequency synthesizer 143 Local oscillator 144 Modulator 145, 147 Bandpass filter 146 Pilot signal detector 148 Demodulator 149 Low-pass filter θ1, θ2 Phase shift Phase difference between θ3 vector 52 and vector 56 Phase difference between θ4 vector 56 and vector 55 Phase difference between θ5 vector 55 and vector 53 a, b, c, d Signal path A1 Amplitude of vector 52 A2 Vector 56 amplitude A3 vector 55 amplitude A4 vector 53 amplitude

Claims (3)

[Claims] 1. A feedforward amplifier which supplies a pilot signal to a distortion elimination loop to automatically control the detection level of the pilot signal to a minimum, and a pilot signal generating means for generating a pilot signal, and the pilot signal generating means. First dividing means for dividing the pilot signal, which is the output signal of the above, into a first signal and a second signal, and an input signal input from the input terminal into a third signal and a fourth signal. Second distributing means for distributing, first vector adjusting means for adjusting the amplitude and phase by inputting the third signal distributed by the second distributing means, and distributing by the first distributing means First synthesizing means for synthesizing the first signal and the third signal whose amplitude and phase have been adjusted by the first vector adjusting means, and an output signal of the first synthesizing means. Amplification means for amplifying the signal, phase shifting means for changing the phase by inputting the second signal distributed by the first distributing means, and fourth phase distributing by the second distributing means A first delaying means for delaying the signal of No. 1, a third distributing means for dividing the output signal of the main amplifying means into a fifth signal and a sixth signal, and a third distributing means for distributing the signal. A second delay means for delaying the fifth signal; a second delay means for combining the sixth signal distributed by the third distributing means and a signal delayed by the first delay means; Synthesizing means, second vector adjusting means for inputting the output signal of the second synthesizing means to adjust the amplitude and phase, auxiliary amplifying means for amplifying the output signal of the second vector adjusting means, The signal delayed by the second delay means and the output signal of the auxiliary amplifying means And a fourth allocating means for allocating the output signal of the third synthesizing means into a seventh signal and an eighth signal, and the fourth allocating means. And a multiplication means for inputting the seventh signal and the output signal of the phase shift means for multiplication, a level detection means for receiving the output signal of the multiplication means and extracting a DC component, and a level detection means for the level detection means. A control means for inputting an output signal to control the first vector adjusting means, the second vector adjusting means and the phase shifting means, and outputting the eighth signal distributed by the fourth distributing means. And an output terminal for controlling the feed forward amplifier. 2. The input signal inputted from the input terminal is supplied to the third signal and the fourth signal by the second distributing means.
Signal is divided into two parts, the fourth signal is input to the second combining means via the first delay means, and the third signal is the third path. A route that is divided into two by the third dividing means via the vector adjusting means, the first synthesizing means, and the main amplifying means and is input to the second synthesizing means as the sixth signal When the signal path b is set, the signal path a and the signal path b have the same amplitude and opposite phase, and a distortion extraction loop that extracts the distortion component of the main amplifying means as an output signal of the second combining means, The output signal of the main amplifying means is divided into the fifth signal and the sixth signal by the third dividing means, and the fifth signal is passed through the second delay means. The signal input to the third synthesizing unit is the signal path c, and the sixth signal is the second signal. The distortion component of the main amplifying means which is input to the forming means and extracted by the second combining means is input to the third combining means via the second vector adjusting means and the auxiliary amplifying means. When the path to be performed is the signal path d, the signal path c and the signal path d have the same amplitude and opposite phase, and the distortion component of the main amplifying means extracted by the distortion extraction loop is set to the third path. 2. A distortion removing loop for combining and canceling by the combining means, and outputting the eighth signal of the two distributions by the fourth distribution means from the output terminal as a distortion-free output signal. The feedforward amplifier described in. 3. When the signal path c and the signal path d have the same amplitude and opposite phase, the second vector adjusting means is controlled by the control means so that the first synthesizing means operates. The feedforward amplifier according to claim 2, wherein the injected first signal is adjusted by the fourth distributor so as to have a minimum value.