JP2002374213A - Distortion compensating circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distortion compensating circuit that reduces multiple reflection to reduce changes in distortion compensation effects by using frequency, thereby carrying out proper distortion compensation. SOLUTION: The distortion compensation circuit is provided with a nonlinear module 6, that has a reverse input output characteristic to that of a distortion compensation object nonlinear element 2, which is a distortion compensating object, a power supply circuit 3 that supplies power to the nonlinear module 6, and isolation sections 5 and 7 that are respectively placed to a pre-stage and a post-stage of the nonlinear module 6, to shut off the multiply reflected wave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a distortion compensating circuit for reducing distortion generated in a nonlinear element in a system for transmitting a plurality of carriers.

[0002]

2. Description of the Related Art In a system for transmitting a plurality of carriers, a dynamic range in which transmission is possible from a minimum input level satisfying a required C / N (carrier-to-noise ratio) to a maximum input level limited by distortion. That is, the distortion generated by the nonlinear elements in the system limits the upper limit of the dynamic range of the system. FIG. 13 is an explanatory diagram illustrating distortion generated in a nonlinear element in a conventional system. Non-linear element 200 in system
Has nonlinear input / output characteristics as shown in FIG. Therefore, the signal of frequency f1 is
, The nonlinear element 200 outputs the frequency f1
In addition, a signal including harmonics such as the frequency 2f1 is output.

By the way, active reports on the distortion compensating circuit for reducing the above-mentioned distortion have been made so far. FIG. 14 is an explanatory diagram for explaining the function of the predistortion type distortion compensating circuit most frequently reported. The conventional distortion compensation circuit 201 has input / output characteristics opposite to those of the nonlinear element 200 to be subjected to distortion compensation. And it is arrange | positioned before the nonlinear element 200, and reduces the energy distribution to the distortion generate | occur | produced in the nonlinear element 200. The input / output characteristics of the circuit obtained by combining the distortion compensation circuit 201 and the nonlinear element are linear as viewed from the input side, and the distortion is reduced.

FIG. 15 is a block diagram showing a configuration of a conventional distortion compensation circuit 201. The distortion compensation circuit 201 includes a signal input terminal 203, a signal output terminal 206, and a signal line 204 between the signal input terminal 203 and the signal output terminal 206.
A nonlinear element 205 provided above;
And a power supply circuit 207 for supplying power to the power supply. In the distortion compensation circuit 201, one nonlinear element 205 corresponds to the entire transmission band, and the power supply circuit 207 sends the nonlinear element 205
The desired characteristics are obtained by changing the power supplied to the power supply.

[0005]

However, according to the above-described technique, the impedance of the nonlinear element 205 changes greatly depending on the supplied power. Since the distortion compensating circuit 201 has no means for blocking multiple reflections, impedance mismatch causes a difference between the nonlinear element 205 and points (P1, P2, etc.) in the distortion compensating circuit 201 or a distortion between the nonlinear element 205 and the nonlinear element 205. Point outside compensation circuit 201 (P
3, P4, P5, etc.), a resonator is formed by multiple reflected waves. As a result, the transmission frequency characteristic of the signal passing through the distortion compensation circuit 201 becomes uneven, and the distortion compensation effect changes greatly depending on the frequency, so that there is a problem that appropriate distortion compensation cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and has as its object to perform appropriate distortion compensation by reducing multiple reflection and reducing a change in distortion compensation effect depending on frequency.

[0007]

In order to achieve the above object, a distortion compensating circuit according to claim 1 comprises a nonlinear means having an input / output characteristic opposite to that of a nonlinear element to be compensated, and And a first multiple reflected wave blocking unit and a second multiple reflected wave blocking unit that are provided before and after the nonlinear unit and block multiple reflected waves. is there.

In the distortion compensating circuit according to the first aspect, the non-linear means has input / output characteristics opposite to those of the non-linear element to be subjected to distortion compensation, and the power supply supplies power to the non-linear means. The first multiple reflected wave blocking unit and the second multiple reflected wave blocking unit are provided before and after the nonlinear unit, and block the multiple reflected waves. As a result, multiple reflection is reduced, and a change in the distortion compensation effect depending on the frequency is reduced.

The distortion compensating circuit according to claim 2 is a demultiplexing means for splitting an input signal into a plurality of paths, and a plurality of filters provided on each of the paths and passing signals of different bands. A plurality of non-linear means provided on each of the paths and having input / output characteristics opposite to those of the non-linear element to be subjected to distortion compensation for each band; and a plurality of non-linear means provided before and after each of the non-linear means. A plurality of first multiple reflected wave blocking means and second multiple reflected wave blocking means for blocking reflected waves, a multiplexing means for multiplexing signals passing through the respective paths, and a power supply to each of the nonlinear means Power supply means.

[0010] In the distortion compensating circuit according to the second aspect, the demultiplexing means demultiplexes the input signal into a plurality of paths, a plurality of filters are provided on each of the paths, and signals of different bands are provided. , A plurality of non-linear means are respectively provided on each path, each band has an input / output characteristic opposite to that of the non-linear element to be subjected to distortion compensation, and a plurality of first multiple reflected wave cut-off means and The two multiple reflection wave cutoff means are provided before and after each nonlinear means, respectively block the multiple reflection waves, the multiplexing means multiplexes the signal passing through each path, and the power supply means Power the means. As a result, multiple reflections are reduced, the change in distortion compensation effect depending on the frequency is reduced, and the degree of distortion improvement can be optimized for each of a plurality of bands.

The distortion compensating circuit according to claim 3 is a demultiplexing means for demultiplexing an input signal into a plurality of paths, and a plurality of filters provided on each of the paths and passing signals in different bands. And one or more non-linear means provided on at least one of the paths and having an input / output characteristic opposite to that of the non-linear element to be subjected to distortion compensation for the corresponding band, and provided before and after the non-linear means. A first multiple reflected wave blocking unit and a second multiple reflected wave blocking unit that block multiple reflected waves, and an attenuating unit that is provided on the path where the nonlinear unit is not provided and attenuates a signal; A multiplexing means for multiplexing the signals passing through the respective paths; and a power supply means for supplying power to the non-linear means.

In the distortion compensating circuit according to the third aspect, the demultiplexing means demultiplexes the input signal into a plurality of paths, a plurality of filters are provided on each path, respectively, and the signals of different bands are provided. And one or a plurality of nonlinear means are provided on at least one path, have input / output characteristics opposite to those of the nonlinear element to be compensated for the corresponding band, and block the first multiple reflected wave. Means and a second multiple reflected wave blocking means are provided before and after the non-linear means to block multiple reflected waves, and attenuating means are provided on a path not provided with the non-linear means to attenuate the signal. , Multiplexing means multiplexes the signals passing through the respective paths, and the power supply means supplies power to the non-linear means. As a result, multiple reflection is reduced, a change in distortion compensation effect depending on the frequency is reduced, and the degree of distortion improvement in a desired band can be optimized.

According to a fourth aspect of the present invention, in the distortion compensating circuit according to the first, second or third aspect, the first multiple reflected wave blocking unit and the second multiple reflected wave blocking unit are used as the first multiple reflected wave blocking unit. This uses an impedance matching circuit.

In the distortion compensating circuit of the present invention, the first multiple reflected wave blocking means and the second multiple reflected wave blocking means are realized by using an impedance matching circuit.

According to a fifth aspect of the present invention, in the distortion compensating circuit according to the first, second or third aspect, the first multiple reflected wave blocking means and the second multiple reflected wave blocking means are used as the first multiple reflected wave blocking means. It uses an isolator.

In the distortion compensating circuit according to the present invention, the first multiple reflected wave cutoff means and the second multiple reflected wave cutoff means are realized by using an isolator.

The distortion compensating circuit according to claim 6 is the distortion compensating circuit according to claim 1, 2, or 3, wherein the first multiple reflected wave blocking means and the second multiple reflected wave blocking means are used as the first multiple reflected wave blocking means. And a circuit in which isolators of the same type are connected in series.

In the distortion compensating circuit according to the present invention, a large isolator can be obtained by using a circuit in which isolators of the same type are connected in series as the first multiple reflected wave blocking means and the second multiple reflected wave blocking means. The amount of ration can be taken.

The distortion compensating circuit according to claim 7 is the distortion compensating circuit according to claim 1, 2, or 3, wherein the first multiple reflected wave blocking unit and the second multiple reflected wave blocking unit are used as the first multiple reflected wave blocking unit. And a circuit in which a plurality of types of isolators are connected in series.

In the distortion compensating circuit according to the present invention, a circuit in which a plurality of types of isolators are connected in series is used as the first multiple reflected wave cutoff means and the second multiple reflected wave cutoff means, so as to cover a wide band. The amount of isolation can be taken.

According to an eighth aspect of the present invention, in the distortion compensation circuit according to any one of the first to seventh aspects, the non-linear means is constituted by a diode which is a non-linear element. .

In the distortion compensating circuit according to the eighth aspect, the nonlinear means is realized by using a diode which is a nonlinear element.

According to a ninth aspect of the present invention, in the distortion compensating circuit according to any one of the first to eighth aspects, the non-linear means includes a plurality of non-linear elements connected to each other. The means supplies power to each of the nonlinear elements independently.

In the distortion compensating circuit according to the ninth aspect, the non-linear means comprises a plurality of non-linear elements connected to each other, and the power supply means supplies the power to each of the non-linear elements independently of each other, thereby providing a desired power. Characteristics can be easily obtained.

The distortion compensating circuit according to claim 10 is:
10. The distortion compensation circuit according to claim 9, wherein the power supply means can independently and variably set the power supplied to each of the nonlinear elements.

In the distortion compensating circuit according to the tenth aspect,
Since the power supply means can independently and variably set the power supplied to each nonlinear element, desired characteristics can be easily obtained.

[0027]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The present invention is not limited by the embodiment.

(First Embodiment) FIG. 1 is a block diagram showing a schematic configuration of a distortion compensation circuit according to a first embodiment of the present invention. The distortion compensation circuit 1 according to the first embodiment includes a signal input terminal 4, a signal output terminal 8, a nonlinear module 6 having input / output characteristics opposite to those of the distortion compensation target nonlinear element 2, which is a distortion compensation target, and a nonlinear module. The power supply circuit 3 includes a power supply circuit 3 that supplies power to the nonlinear module 6 and isolation units 5 and 7 that are provided before and after the nonlinear module 6 and that block multiple reflected waves.

The nonlinear module 6 has input / output characteristics opposite to those of the nonlinear element 2 to be compensated for distortion. As a result, the input / output characteristics of the circuit obtained by combining the distortion compensation circuit 1 and the distortion compensation target nonlinear element 2 become linear as viewed from the input side. Power supply circuit 3
Supplies variable power to the nonlinear module 6. The isolation units 5 and 7 block multiple reflected waves.
Thus, no matter how the power supply from the power supply circuit 3 to the nonlinear module 6 is set, multiple reflection can be suppressed, and a stable operation can be obtained. The isolation units 5 and 7 and the non-linear module 6 constitute a distortion generation unit 9.

Next, the isolation units 5 and 7 will be described. FIG. 2 is a circuit diagram showing an example in which an impedance matching circuit is used as the isolation units 5 and 7 shown in FIG. 2A shows a case where the resistor 11 is inserted into the signal line, FIG. 2B shows a case where the resistor 12 is connected between the signal line and the ground, and FIG. Using three resistors 13, 14, and 15,
This figure shows a case where a π-type ATT (attenuator) is configured and inserted into a signal line. Further, an isolator can be used as the isolation units 5 and 7.

FIG. 3 is a circuit diagram showing an example in which a circuit in which isolators of the same type are connected in series is used as the isolation units 5 and 7 shown in FIG. In this circuit, the same type of isolator 2 having the same frequency characteristic
1, 2, and 23 are connected in series to obtain a large amount of isolation at a predetermined frequency. FIG.
FIG. 6 is a circuit diagram showing an example in which a circuit in which a plurality of types of isolators are connected in series is used as the isolation units 5 and 7 shown in FIG. In this circuit, a plurality of types of isolators 21, 22, and 23 having different frequency characteristics are connected in series to obtain an isolation amount over a wide band. Although FIGS. 3 and 4 show a case where there are three isolators, the number of isolators may be two or four or more. Next, the nonlinear module 6 and the power supply circuit 3 will be described.

FIG. 5 shows the nonlinear module 6 shown in FIG.
And a circuit section showing an example of the power supply circuit 3. In this example, the nonlinear module 6 includes one diode 32 which is a nonlinear element, decoupling capacitors 31 and 33 provided before and after the diode 32 to cut off a DC component, an anode of the diode 32 and the power supply circuit 3. And a choke coil 35 connected between the cathode of the diode 32 and the ground terminal of the power supply circuit 3. The decoupling capacitors 31 and 33 are
It is provided before and after the diode 32, and passes only the AC component. The power supply circuit 3 supplies variable power to the diode 32. The choke coil 35 is connected to the power supply circuit 3
Suppress the transmission of the AC component to the

FIG. 6 shows the nonlinear module 6 shown in FIG.
And a circuit section showing another example of the power supply circuit 3. In this example, the power supply circuit 3 includes power supply circuits 3a and 3b that supply independently set variable power.
The nonlinear module 6 includes two diodes 42 and 44 that are nonlinear elements, decoupling capacitors 41 and 45 provided before the diode 42 and after the diode 44, and the diode 42 and the diode 4.
4 and a capacitor 43 connected between the
A choke coil 46 connected between the anode of the power supply circuit 3a and the plus terminal of the power supply circuit 3a; a choke coil 47 connected between the cathode of the diode 42 and the ground terminal of the power supply circuit 3; It has a choke coil 48 connected between the positive terminal of the power supply circuit 3 b and a choke coil 49 connected between the cathode of the diode 44 and the ground terminal of the power supply circuit 3.

The diodes 42 and 44 are connected in series in the same direction. The capacitor 43 is arranged to prevent DC current flowing through one diode from flowing through the other diode. The power supply circuit 3a
Independently set variable power is supplied to the diode 42, and the power supply circuit 3b supplies independently set variable power to the diode 44. Choke coils 46-49
Suppresses transmission of an AC component to the power supply circuit 3.

FIG. 7 shows the nonlinear module 6 shown in FIG.
And a circuit section showing still another example of the power supply circuit 3.
In this example, the nonlinear module 6 includes two diodes 52 and 54, which are nonlinear elements, and a diode 5
Decoupling capacitors 51 and 55 provided before the diode 2 and after the diode 54;
2 and a capacitor 53 connected between the diode 54
A choke coil 56 connected between the anode of the diode 52 and the plus terminal of the power supply circuit 3a; a choke coil 57 connected between the cathode of the diode 52 and the ground terminal of the power supply circuit 3; And a choke coil 58 connected between the anode of the diode 54 and the plus terminal of the power supply circuit 3b.

The diodes 52 and 54 are connected in series in opposite directions. The capacitor 53 is arranged to prevent DC current flowing in one diode from flowing in the other diode. The power supply circuit 3a supplies independently set variable power to the diode 52, and the power supply circuit 3b supplies independently set variable power to the diode 54. The choke coils 56 to 59 suppress transmission of an AC component to the power supply circuit 3.

FIG. 8 shows the nonlinear module 6 shown in FIG.
And a circuit section showing still another example of the power supply circuit 3.
In this example, the nonlinear module 6 includes two diodes 64 and 67, which are nonlinear elements, and a diode 6
4 and decoupling capacitors 63 and 65 provided before and after the diode 67, and decoupling capacitors 66 and 6 provided before and after the diode 67.
8, a choke coil 69 connected between the anode of the diode 67 and the positive terminal of the power supply circuit 3a; a choke coil 70 connected between the cathode of the diode 67 and the ground terminal of the power supply circuit 3a; 6
4 and a choke coil 62 connected between the cathode of the diode 64 and the ground terminal of the power supply circuit 3b.

The diodes 64 and 67 are connected in parallel in the same direction. The power supply circuit 3a supplies an independently set variable power to the diode 67,
b supplies an independently set variable power to the diode 64. Choke coils 61, 62, 69 and 70
Suppresses transmission of an AC component to the power supply circuit 3.

FIG. 9 shows the nonlinear module 6 shown in FIG.
And a circuit section showing still another example of the power supply circuit 3.
In this example, the nonlinear module 6 includes two diodes 74 and 77, which are nonlinear elements, and a diode 7
4 and decoupling capacitors 73 and 75 provided before and after the diode 77, and decoupling capacitors 76 and 7 provided before and after the diode 77, respectively.
8, a choke coil 79 connected between the anode of the diode 77 and the plus terminal of the power supply circuit 3a; a choke coil 80 connected between the cathode of the diode 77 and the ground terminal of the power supply circuit 3a; 7
4 and a choke coil 72 connected between the positive terminal of the power supply circuit 3b and a choke coil 71 connected between the cathode of the diode 74 and the ground terminal of the power supply circuit 3b.

The diodes 74 and 77 are connected in parallel in opposite directions. The power supply circuit 3a supplies an independently set variable power to the diode 77, and the power supply circuit 3b
Supplies an independently set variable power to the diode 74. Choke coils 71, 72, 79 and 80
Suppresses transmission of an AC component to the power supply circuit 3.

FIGS. 5 to 9 show examples in which one or two diodes are non-linear elements. However, even if three or more diodes are connected in series or in parallel, the non-linear module 6 is similarly constructed. can do. The non-linear module 6 corresponds to the non-linear means of the present invention, and the isolation units 5 and 7 correspond to the first and second multi-reflected wave cut-off means of the present invention.

The operation of the first embodiment in the above configuration will be described. In the distortion compensation circuit 1 according to the first embodiment, an input signal from the signal input terminal 4 passes through the isolation unit 5, the nonlinear module 6, and the isolation unit 7. In the nonlinear module 6, the energy distribution to the distortion generated in the distortion compensation target nonlinear element 2 is reduced. Then, a signal is output from the signal output terminal 8. In addition, the isolation units 5 and 7 suppress multiple reflection and reduce a change in the distortion compensation effect depending on the frequency.

As described above, according to the first embodiment,
The nonlinear module 6 has input / output characteristics opposite to those of the nonlinear element 2 for distortion compensation, the power supply circuit 3 supplies power to the nonlinear module 6, and the isolation units 5 and 7
It is provided before and after the nonlinear module 6, and blocks multiple reflected waves. This reduces multiple reflections,
Since the change in the distortion compensation effect depending on the frequency is reduced, appropriate distortion compensation can be performed.

(Embodiment 2) Embodiment 2 of the present invention
Is designed to perform distortion compensation for each of a plurality of bands in order to perform appropriate distortion compensation over a wide band. FIG.
0 is an explanatory diagram showing the configuration and operation of the distortion compensation circuit according to the second embodiment of the present invention.

The distortion compensating circuit 81 of the second embodiment includes a signal input terminal 4, a signal output terminal 8, a distributor 83 for splitting an input signal into a plurality of paths 88, 93 and 98, A plurality of filters 84 and 8 respectively provided on 93 and 98 and passing signals of different bands, respectively.
9 and 94, and on each of the paths 88, 93 and 98, the distortion compensating nonlinear element 2
Nonlinear modules 8 having input / output characteristics opposite to
6, 91 and 96, and isolation units 85 and 8 provided before and after the nonlinear module 86.
7, isolation units 90 and 92 provided before and after the nonlinear module 91, isolation units 95 and 97 provided before and after the nonlinear module 96, and respective paths 88, 93 and 98.
And a power supply circuit 100 for supplying power to each of the nonlinear modules 86, 91 and 96.

The distributor 83 transmits the input signal to a plurality of paths 8
Demultiplex to 8, 93 and 98. A plurality of filters 84,
89 and 94 are provided on each of the paths 88, 93 and 98, respectively, and pass signals of different bands. The filter 84 is a low-pass filter or a band-pass filter, and passes the lowest band component. The filter 89 is a band-pass filter, and passes a component in the center band. The filter 94 is a high-pass filter or a band-pass filter, and passes the highest band component. As a result, the input signal is separated into a plurality of bands (three bands in this example).

A plurality of nonlinear modules 86, 91, and 96 are provided on each of the paths 88, 93, and 98, respectively, and have input / output characteristics opposite to those of the distortion compensation target nonlinear element 2 for each band. The nonlinear module 86 has input / output characteristics opposite to those of the distortion compensation target nonlinear element 2 for the lowest band. The nonlinear module 91 has input / output characteristics opposite to those of the distortion compensation target nonlinear element 2 in the center band. The nonlinear module 96 has input / output characteristics opposite to those of the distortion compensation target nonlinear element 2 for the highest band.
The configuration of the nonlinear modules 86, 91 and 96 is shown in FIG.
9 is the same as the nonlinear module 6 of the first embodiment shown in FIG.

Isolation parts 85, 87, 90, 9
The configurations of 2, 95 and 97 are the same as the isolation units 5 and 7 of the first embodiment shown in FIGS. The mixer 99 combines the signals that have passed through the respective paths 88, 93 and 98 and outputs the combined signals. The power supply circuit 100 shown in FIG.
To the number of non-linear modules (three in this example). The power supply circuit 3 according to the first embodiment shown in FIG. Supply. The distributor 83, the mixer 99, the filters 84, 89 and 94, the isolation units 85, 87, 90, 92, 95 and 97, and the non-linear modules 86, 91 and 96 constitute a distortion generation unit 82.

FIG. 10 shows an example in which three paths are provided to improve distortion in three bands. However, a circuit in which four or more paths are provided to improve distortion in four or more bands is similarly configured. can do. Note that the nonlinear modules 86 and 91
And 96 correspond to the non-linear means of the present invention, and the isolation units 85, 90 and 95 correspond to the first means of the present invention.
And the isolation unit 8
Reference numerals 7, 92 and 97 correspond to the second multiple reflection wave blocking means of the present invention, the distributor 83 corresponds to the demultiplexing means of the present invention, and the mixer 99 corresponds to the multiplexing means of the present invention. I do.

In the above configuration, the operation of the second embodiment will be described. In the distortion compensation circuit 81 according to the second embodiment, the input signal from the signal input terminal 4 is split by the splitter 83 and passes through the filters 84, 89 and 94.
Thereby, the input signal is divided into three bands. The signals in each band are separated by isolation units 85, 90, 95,
It passes through the nonlinear modules 86, 91, 96 and the isolation units 87, 92, 97, respectively. In the nonlinear modules 86, 91, and 96, the energy distribution to the distortion generated in the distortion compensation target nonlinear element 2 is reduced. Then, the signals in each band are multiplexed by the mixer 99 and output from the signal output terminal 8. Also, the isolation unit 85,
87, 90, 92, 95, and 97 suppress multiple reflection and reduce a change in distortion compensation effect depending on frequency.

As described above, according to the second embodiment,
A splitter 83 splits the input signal into a plurality of paths 88, 93 and 98, and a plurality of filters 84, 89 and 94.
Are provided on each of the paths 88, 93 and 98, respectively, to pass signals of different bands, respectively, and a plurality of nonlinear modules 86, 91 and 96
3 and 98, respectively, and has input / output characteristics opposite to those of the distortion compensation target nonlinear element 2 for each band, and includes isolation units 85, 87, 90, 92, 95 and 9
7 are provided before and after each of the nonlinear modules 86, 91 and 96, respectively, to block multiple reflected waves,
The mixer 99 multiplexes the signals passing through the respective paths 88, 93 and 98, and the power supply circuit 100 supplies power to the respective nonlinear modules 86, 91 and 96. This allows
Since multiple reflections are reduced, a change in distortion compensation effect depending on frequency is reduced, and a degree of distortion improvement can be optimized for each of a plurality of bands, so that appropriate distortion compensation can be performed over a wide band.

(Embodiment 3) Embodiment 3 of the present invention
Is designed to perform distortion compensation only for a desired band for which distortion compensation is desired. FIG. 11 is an explanatory diagram illustrating the configuration and operation of the distortion compensation circuit according to the third embodiment of the present invention.

The distortion compensation circuit 101 according to the third embodiment includes a signal input terminal 4, a signal output terminal 8, and a distributor 103 for splitting an input signal into a plurality of paths 108, 111 and 114.
And a plurality of filters 104, 109, and 112 provided on the paths 108, 111, and 114, respectively, for passing signals in different bands, and the distortion compensation target nonlinear element 2 provided on the path 108 for the corresponding band. Module 10 having input / output characteristics opposite to
6, isolation units 105 and 107 provided before and after the nonlinear module 106, and A provided on paths 111 and 114 for attenuating signals.
TTs 110 and 113, a mixer 115 for multiplexing signals passing through the respective paths 108, 111 and 114, and a power supply circuit 116 for supplying power to the nonlinear module 106
And

The distributor 103 converts the input signal into a plurality of paths 1
Demultiplex to 08, 111 and 114. The plurality of filters 104, 109 and 112 are connected to respective paths 108, 111
And 114, respectively, to pass signals of different bands. The filter 104 is a low-pass filter or a band-pass filter, and passes the lowest band component. The filter 109 is a band-pass filter, and passes a component in the center band. The filter 112 is a high-pass filter or a band-pass filter, and passes the highest band component. As a result, the input signal is separated into a plurality of bands (three bands in this example).

The nonlinear module 106 is provided on the path 108 and has input / output characteristics opposite to those of the distortion compensation target nonlinear element 2 in the lowest band. Nonlinear module 1
The configuration of 06 is the same as the nonlinear module 6 of the first embodiment shown in FIGS. Isolation section 10
The configurations of 5 and 107 are the same as the isolation units 5 and 7 of the first embodiment shown in FIGS. A
The TTs 110 and 113 are provided on the paths 111 and 114 where the nonlinear module 106 is not provided, and attenuate the signal.

The mixer 115 combines the signals passing through the respective paths 108, 111 and 114 and outputs the combined signal. Power supply circuit 116 has the same configuration as power supply circuit 3 of the first embodiment shown in FIGS. 5 to 9 and supplies power to nonlinear module 106. Distributor 103, mixer 115, filter 1
04, 109 and 112, isolation unit 105
And 107, nonlinear module 106, and AT
T110 and 113 constitute distortion generating section 102.

In FIG. 11, three bands are assumed, but a circuit assuming two or four or more bands can also be configured. In this case, the same number of paths as the assumed bands are provided. Further, FIG. 11 shows an example in which the distortion of the lowest band is improved, but another band may be improved. FIG. 11 shows an example in which the distortion in one band is improved, but a circuit for improving the distortion in two or more bands can be similarly configured. In this case, a nonlinear module and an isolation unit are provided instead of the ATT on a path corresponding to a band in which distortion is to be improved, and a circuit similar to the power supply circuit 100 of the second embodiment is provided as a power supply circuit.

The non-linear module 106 corresponds to the non-linear means of the present invention, and the isolation units 105 and 107 correspond to the first and second multi-reflected wave blocking means of the present invention. , Distributor 103
Corresponds to the demultiplexing means of the present invention, and ATTs 110 and 113 correspond to the attenuating means of the present invention.
Corresponds to the multiplexing means of the present invention.

The operation of the third embodiment having the above configuration will be described. In the distortion compensation circuit 101 according to the third embodiment, the input signal from the signal input terminal 4
3 and passes through filters 104, 109 and 112. Thereby, the input signal is divided into three bands. The signal in the lowest band is
05, through the nonlinear module 106 and the isolation unit 107.

In the nonlinear module 106, the energy distribution to the distortion in the lowest band is reduced. The signal in the middle band and the signal in the highest band are A
Attenuates through TTs 110 and 113. Then, the signals of each band are multiplexed by the mixer 115, and the signal
Output from In addition, the isolation units 105 and 107 suppress multiple reflection and reduce a change in distortion compensation effect depending on the frequency.

As described above, according to the third embodiment,
The distributor 103 transfers the input signal to a plurality of paths 108 and 111.
And 114, and a plurality of filters 104, 109
And 112 are provided on each of the paths 108, 111 and 114, respectively, to pass signals of different bands, and one or more non-linear modules 106 are provided on at least one of the paths 108 for corresponding bands. The input / output characteristics are opposite to those of the nonlinear element 2 to be compensated for distortion. Isolation units 105 and 107 are provided before and after the nonlinear module 106 to block multiple reflected waves. 106 are provided on paths 111 and 114 where no signal is provided to attenuate the signal and
Combine the signals passing through the paths 108, 111 and 114, and the power supply circuit 116
To supply power. This reduces multiple reflections,
Changes in the distortion compensation effect depending on the frequency are reduced,
In addition, since the degree of distortion improvement in a desired band can be optimized, appropriate distortion compensation can be performed on a desired band.

(Embodiment 4) Embodiment 4 of the present invention
In the third embodiment, the paths of the bands for which distortion compensation is not performed are combined into one. FIG. 12 is an explanatory diagram showing the configuration and operation of another distortion compensation circuit according to the fourth embodiment of the present invention.

The distortion compensating circuit 121 according to the fourth embodiment includes a signal input terminal 4, a signal output terminal 8, a distributor 123 for splitting an input signal into a plurality of paths 128 and 131, , And a plurality of filters 124 and 129 for passing signals in different bands, and a nonlinear module 126 provided on a path 128 and having input / output characteristics opposite to those of the distortion compensation target nonlinear element 2 for the corresponding band. And the nonlinear module 1
26, isolation units 125 and 127 provided before and after 26, an ATT 130 provided on a path 131 to attenuate signals, and paths 128 and 13
The mixer 132 includes a mixer 132 that multiplexes the signals that have passed through the power supply 1 and a power supply circuit 133 that supplies power to the nonlinear module 126.

The distributor 123 converts an input signal into a plurality of paths 1
Demultiplex to 28 and 131. The filter 124 is provided on the path 128 and passes a signal in a band for performing distortion compensation. The filter 129 is provided on the path 131 and collectively passes signals in a band for which distortion compensation is not performed. The filter 124 is a low-pass filter or a band-pass filter, and passes the lowest band component. The filter 129 is a high-pass filter or a band-pass filter, and passes components in the middle band and the highest band of the input signal.

The nonlinear module 126 is provided on the path 128 and has input / output characteristics opposite to those of the distortion compensation target nonlinear element 2 in the lowest band. Nonlinear module 1
The configuration of reference numeral 26 is the same as that of the nonlinear module 6 of the first embodiment shown in FIGS. Isolation section 12
The configurations of 5 and 127 are the same as the isolation units 5 and 7 of the first embodiment shown in FIGS. A
The TT 130 is provided on the path 131 where the nonlinear module 126 is not provided, and attenuates a signal.

The mixer 132 is connected to each of the paths 128 and 13.
1 are multiplexed and output. Power supply circuit 133
Has the same configuration as the power supply circuit 3 of the first embodiment shown in FIGS. 5 to 9 and supplies power to the nonlinear module 126. The distributor 123, the mixer 132, the filters 124 and 129, the isolation units 125 and 127, the nonlinear module 126, and the ATT 130 form the distortion generation unit 122.

In FIG. 12, three bands are assumed, but a circuit assuming two or four or more bands can also be configured. FIG. 12 shows an example in which the distortion in the lowest band is improved, but another band may be improved. FIG. 12 shows an example in which the distortion of one band is improved, but a circuit that improves the distortion of two or more bands can be similarly configured. For example, to improve the distortion of M bands from the low frequency side or the high frequency side in the N bands, (M + 1) paths are provided. Then, a nonlinear module and an isolation unit are provided on a path corresponding to a band in which distortion is desired to be improved, and a circuit similar to the power supply circuit 100 of the second embodiment is provided as a power supply circuit.

The non-linear module 126 corresponds to the non-linear means of the present invention, and the isolation units 125 and 127 correspond to the first and second multi-reflected wave cut-off means of the present invention. , Distributor 123
Corresponds to the demultiplexing means of the present invention, the ATT 130 corresponds to the attenuating means of the present invention, and the mixer 132 corresponds to the multiplexing means of the present invention.

In the above configuration, the operation of the fourth embodiment will be described. In the distortion compensating circuit 121 of the fourth embodiment, the input signal from the signal input terminal 4
3 and passes through filters 124 and 129. Thereby, the input signal is divided into the lowest band, the middle band and the highest band. The signal of the lowest band passes through the isolation unit 125, the nonlinear module 126, and the isolation unit 127.

In the non-linear module 126, the energy allocation to distortion in the lowest band is reduced. The signals in the middle band and the highest band are ATT1
Decay through 30. Then, the signals in each band are multiplexed by the mixer 132 and output from the signal output terminal 8. Further, the isolation units 125 and 127 suppress multiple reflection and reduce a change in distortion compensation effect depending on the frequency. As described above, according to the fourth embodiment,
Even when the paths of the band for which distortion compensation is not performed are combined,
The same effect as in the third embodiment can be obtained.

[0071]

As described above, according to the distortion compensating circuit of the present invention (claim 1), the non-linear means has an input / output characteristic opposite to that of the non-linear element to be compensated for, and the power supply means has a non-linear characteristic. The means is supplied with power, and the first multiple reflected wave blocking means and the second multiple reflected wave blocking means are provided before and after the nonlinear means, and block the multiple reflected waves. This allows
Since multiple reflections are reduced and a change in distortion compensation effect depending on the frequency is reduced, appropriate distortion compensation can be performed.

Further, the distortion compensating circuit of the present invention (Claim 2)
The demultiplexing means demultiplexes the input signal into a plurality of paths, a plurality of filters are provided on each path, respectively, signals of different bands are passed, and a plurality of non-linear means are provided on each path. Each of the bands has input / output characteristics opposite to those of the nonlinear element for which distortion is to be compensated for each band, and a plurality of first multiple reflected wave cutoff means and second multiple reflected wave cutoff means are provided in front of each nonlinear means. And at the subsequent stage, respectively, to cut off the multiple reflected waves, to combine the signals passing through the respective paths, and to supply the power to the non-linear means by the power supply. As a result, multiple reflections are reduced, the variation of the distortion compensation effect depending on the frequency is reduced, and the degree of distortion improvement can be optimized for each of a plurality of bands. Can be.

A distortion compensation circuit according to the present invention (claim 3)
The demultiplexing unit demultiplexes the input signal into a plurality of paths, a plurality of filters are provided on each of the paths, respectively, passes signals in different bands, and one or a plurality of non-linear means includes at least The first multi-reflected wave cutoff means and the second multi-reflected wave cutoff means are provided on one path and have input / output characteristics opposite to those of the nonlinear element to be subjected to distortion compensation for the corresponding band. Provided before and after to block multiple reflected waves, attenuating means is provided on a path where the non-linear means is not provided, attenuates the signal,
The multiplexing unit multiplexes the signals passing through the respective paths, and the power supply unit supplies power to the non-linear unit. As a result, multiple reflection is reduced, a change in the distortion compensation effect depending on the frequency is reduced, and the degree of distortion improvement in a desired band can be optimized, so that appropriate distortion compensation is performed for a desired band. be able to.

Further, the distortion compensating circuit of the present invention (Claim 4)
Can implement the first multiple reflected wave cutoff means and the second multiple reflected wave cutoff means using an impedance matching circuit.

Further, the distortion compensating circuit of the present invention (claim 5)
Can implement the first multiple reflected wave blocking means and the second multiple reflected wave blocking means using an isolator.

A distortion compensation circuit according to the present invention (claim 6)
Since a circuit in which the same type of isolators are connected in series is used as the first multiple reflected wave blocking means and the second multiple reflected wave blocking means, a large isolation amount can be obtained.

Further, the distortion compensation circuit of the present invention (claim 7)
Is a circuit in which multiple types of isolators are connected in series.
, The isolation amount can be obtained over a wide band.

Further, the distortion compensating circuit of the present invention (claim 8)
Can implement non-linear means using a diode which is a non-linear element.

Further, the distortion compensating circuit of the present invention (claim 9)
Consists of a nonlinear means connecting a plurality of nonlinear elements,
Since the power supply unit supplies power to each nonlinear element independently, desired characteristics can be easily obtained.

Further, the distortion compensating circuit of the present invention (claim 1)
In the case of (0), since the power supply unit can independently and variably set the power supplied to each nonlinear element, desired characteristics can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a distortion compensation circuit according to a first embodiment of the present invention;

FIGS. 2A, 2B, and 2C are circuit diagrams showing examples in which an impedance matching circuit is used as the isolation unit shown in FIG.

FIG. 3 is a circuit diagram showing an example in which a circuit in which the same type of isolators are connected in series is used as the isolation unit shown in FIG. 1;

FIG. 4 is a circuit diagram showing an example in which a circuit in which a plurality of types of isolators are connected in series is used as the isolation unit shown in FIG.

FIG. 5 is a circuit diagram illustrating an example of a nonlinear module and a power supply circuit illustrated in FIG. 1;

FIG. 6 is a circuit diagram showing another example of the nonlinear module and the power supply circuit shown in FIG. 1;

FIG. 7 is a circuit diagram showing still another example of the nonlinear module and the power supply circuit shown in FIG. 1;

FIG. 8 is a circuit diagram illustrating still another example of the nonlinear module and the power supply circuit illustrated in FIG. 1;

FIG. 9 is a circuit diagram illustrating still another example of the nonlinear module and the power supply circuit illustrated in FIG. 1;

FIG. 10 is an explanatory diagram illustrating a configuration and an operation of a distortion compensation circuit according to a second embodiment of the present invention;

FIG. 11 is an explanatory diagram illustrating a configuration and an operation of a distortion compensation circuit according to a third embodiment of the present invention;

FIG. 12 is an explanatory diagram illustrating a configuration and an operation of a distortion compensation circuit according to a fourth embodiment of the present invention;

FIG. 13 is an explanatory diagram illustrating distortion generated in a nonlinear element in a conventional system.

FIG. 14 is an explanatory diagram illustrating functions of a conventional distortion compensation circuit.

FIG. 15 is a block diagram showing a configuration of a conventional distortion compensation circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Distortion compensation circuit 2 Non-linear element for distortion compensation 3, 100, 116, 133 Power supply circuit 4 Signal input terminal 5, 7, 85, 87, 90, 92, 95, 97 Isolation unit 6, 86, 91, 96, 106 , 126 Nonlinear module 8 Signal output terminal 9, 82, 102, 122 Distortion generator 21 to 23, 26 to 28 Isolator 32, 42, 44, 52, 54, 64, 67, 74, 7
7 Diodes 84, 89, 94, 104, 109, 112, 124,
129 filters 88, 93, 98, 108, 111, 114, 128,
131 path 83,103,123 distributor 99,115,132 mixer 110,113,130 attenuator (ATT)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Seiya Shinoda 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. F-term (reference) 5J090 AA04 AA21 AA41 CA22 CA75 CA81 FA08 FA10 FA20 GN03 GN04 GN11 HA19 HA29 HA33 KA12 KA29 KA49 KA68 MA08 SA14 TA01 TA03 5K052 AA02 BB14 DD15 FF32

Claims (10)

[Claims] A non-linear element having an input / output characteristic opposite to that of a non-linear element to be compensated; a power supply for supplying power to the non-linear element; a multi-reflected wave provided at a stage before and after the non-linear unit. A first multi-reflected wave cutoff means and a second multi-reflected wave cutoff means for shutting off the distortion. 2. A demultiplexing means for demultiplexing an input signal into a plurality of paths, a plurality of filters provided on each of the paths, respectively, for passing signals of different bands, and a plurality of filters provided on each of the paths, respectively. A plurality of non-linear means having input / output characteristics opposite to those of the non-linear element to be subjected to distortion compensation for each of the bands; Multi-reflected wave cutoff means and second multi-reflected wave cutoff means, multiplexing means for multiplexing signals passing through the respective paths, and power supply means for supplying power to the non-linear means. Characteristic distortion compensation circuit. 3. A demultiplexing means for demultiplexing an input signal into a plurality of paths, a plurality of filters provided on each of the paths, respectively, for passing signals of different bands, and a plurality of filters provided on at least one of the paths. And one or more non-linear means having an input / output characteristic opposite to that of the non-linear element to be subjected to distortion compensation for the corresponding band, and a first means provided before and after the non-linear means to block multiple reflected waves. Multi-reflected wave blocking means and second multi-reflected wave blocking means, provided on the path where the non-linear means is not provided, and attenuating means for attenuating a signal; And a power supply unit for supplying power to the non-linear unit. 4. The distortion compensating circuit according to claim 1, wherein said first multiple reflected wave blocking means and said second multiple reflected wave blocking means are impedance matching circuits. 5. The distortion compensating circuit according to claim 1, wherein said first multiple reflected wave blocking means and said second multiple reflected wave blocking means are isolators. 6. The apparatus according to claim 1, wherein said first multiple reflected wave blocking means and said second multiple reflected wave blocking means are circuits in which isolators of the same type are connected in series.
4. The distortion compensation circuit according to 2 or 3. 7. The circuit according to claim 1, wherein said first multiple reflected wave cutoff means and said second multiple reflected wave cutoff means are circuits in which a plurality of types of isolators are connected in series. The distortion compensation circuit as described. 8. The apparatus according to claim 1, wherein said non-linear means is constituted by a diode which is a non-linear element.
8. The distortion compensation circuit according to any one of claims 7 to 7. 9. The apparatus according to claim 1, wherein said non-linear means connects a plurality of non-linear elements, and said power supply means supplies power to each of said non-linear elements independently.
9. The distortion compensation circuit according to any one of claims 8 to 8. 10. The distortion compensation circuit according to claim 9, wherein said power supply means can independently and variably set the power supplied to each of said nonlinear elements.