JP3553308B2 - Distortion compensation amplifier - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a distortion compensation amplifier used for a base station and a relay device in a mobile communication system such as a mobile phone and a mobile phone.
[0002]
[Prior art]
For example, the relay device relay-amplifies radio waves from the base station and retransmits the radio waves to the mobile station. In this case, although the amplifying radio multi-channel simultaneously, in this case, in order to suppress the intermodulation distortion generation caused by the nonlinearity of the common amplifier, a self-adjustable type feedforward as a non-linear distortion compensation circuit A device mounted with a distortion compensation amplifier called a (SAFF: Self Adjusting Feed Forward) circuit is used.
[0003]
FIG. 2 is a circuit diagram of a conventional feedforward distortion compensation amplifier. In the figure, 1, 4 and 9 are directional couplers, 2 and 7 are vector adjusters, 3 is a main amplifier, 5 and 6 are delay lines, 8 is an auxiliary amplifier, 10 is an amplifier, 11 is a pilot signal generator, 12 detector, 13 a receiver of the pilot signal, 14 is a control circuit.
The circuit between the directional coupler 1 and 4 a distortion detection loop for detecting the intermodulation distortion generated when the input multi-frequency signal is amplified by the main amplifier 3, the distortion components such as noise (error component) .
The circuit between the directional couplers 4 and 9 is a distortion removal loop, and a signal obtained by amplifying the error component detected by the above-described distortion detection loop to a desired value by the auxiliary amplifier 8 and inverting the phase, and a delay line 6 and the amplified signal including the distortion component input to the directional coupler 9 through the negative phase adder 6. In this way, an amplified signal from which the distortion component generated when amplified by the main amplifier 3 is removed (canceled) is output.
[0004]
The vector adjusters 2 and 7, and the pilot signal generator 11, the detector 12, the receiver 13, and the control circuit 14 set the optimum adjustment value when the distortion component extracted by the distortion detection loop is removed by the distortion removal loop. It is provided for.
The detection output of the detector 12 for detecting the distortion component amplified by the amplifier 10 and the pilot signal from the receiver 13 for receiving and detecting the pilot signal are input to the control circuit 14, and the distortion compensation is performed by digital signal processing. After determining the optimum value, the amplitude / phase control signal is input to the vector adjusters 2 and 7.
[0005]
That is, the vector adjuster 2 of the distortion detection loop extracts and amplifies the distortion component detected by the distortion detection loop by the amplifier 10 and inputs the signal detected by the detector 12 to the control circuit 14 to obtain the optimum control value. The phase and amplitude are adjusted by the output control signal, and the self-adjustment is performed so that the detection output of the amplified signal is minimized.
On the other hand, the vector adjuster 7 of the distortion removal loop detects the level of the pilot signal of, for example, an out-of-band frequency injected to the output side of the main amplifier 3 of the distortion detection loop from the output side of the directional coupler 9 and performs correlation detection. After extracting by the receiver 13 having a narrow band detector such as a detector and inputting it to the control circuit 14 to obtain the optimum control value, the phase and amplitude are adjusted by the output control signal, and the extraction level is minimized. Self-adjusted to be.
[0006]
When actually using the distortion compensation amplifier, in some failure occurs and when a predetermined distortion compensation function is no longer fulfill, in the distortion component is output becomes a system down, it can not be service to the user .
In order to prevent the system from going down due to such a failure, the control circuit 14 monitors the output of the detector 12 and the output of the receiver 13, and when the detection output becomes larger than a certain value, and when the output of the pilot signal receiver 13 When is not smaller than a certain level, the control signal a is output to turn off the power of the main amplifier 3 to stop the amplification function of the distortion compensation amplifier.
[0007]
[Problems to be solved by the invention]
However, the multi-frequency signal when the Ru completely terminate the amplification function in the event of a fault is not output, there is a problem that the line can not be used at all.
[0008]
An object of the present invention is to alleviate the problem of the prior art that the line cannot be used at all when the distortion compensation amplifier, that is, the multi-frequency common amplifier fails and the distortion compensation operation becomes abnormal. It is an object of the present invention to provide a distortion compensating amplifier which can be used.
[0009]
[Means for Solving the Problems]
In order to achieve this object, a distortion compensating amplifier according to the present invention comprises a signal obtained by amplifying an input signal by a main amplifier via a first vector adjuster and a signal having an inverted phase via a first delay line. And a distortion detection loop for detecting a distortion component, and a signal obtained by amplifying the distortion component by an auxiliary amplifier via a second vector adjuster and a signal amplified by the main amplifier via a second delay line. And a distortion removal loop that cancels out the distortion component and outputs the detection level of the input signal extracted from the distortion detection loop and the detection level of the pilot signal that is injected into the detection loop and extracted from the distortion removal loop, respectively. A distortion compensating amplifier having a control circuit for adjusting the amount of attenuation and the amount of phase of the first vector adjuster and the second vector adjuster,
A bypass cable wired between an input terminal and an output terminal of the distortion compensation amplifier,
An input-side switch for switching and inputting the input signal to any one of the distortion compensation amplifier and the bypass cable;
An output-side switch that switches and outputs one of an output signal from the distortion compensation amplifier and an output signal from the bypass cable,
The control circuit, wherein the detection level is monitored, when the該検wave level is greater than a predetermined threshold value, the control for switching between the output-side switch and the input-side switch to the bypass cable side It has a configuration characterized by performing.
[0010]
Further, in the distortion compensation amplifier according to the present invention, a distortion component is detected by a signal obtained by amplifying an input signal by a main amplifier via a first vector adjuster and an inverted phase signal of the input signal via a first delay line. A distortion detection loop that cancels the distortion component by a signal amplified by an auxiliary amplifier via a second vector adjuster and a signal amplified by the main amplifier via a second delay line. And a detection level of an input signal extracted from the distortion detection loop and the detection level of a pilot signal extracted from the distortion removal loop and injected into the detection loop. A distortion compensating amplifier comprising a first vector adjuster and a control circuit for adjusting the amount of attenuation and the amount of phase of the second vector adjuster,
A bypass cable wired between an input terminal and an output terminal of the distortion compensation amplifier,
An input-side switch for switching and inputting the input signal to any one of the distortion compensation amplifier and the bypass cable;
An output-side switch that switches and outputs one of an output signal from the distortion compensation amplifier and an output signal from the bypass cable,
The control circuit monitors a detection level of the pilot signal, and performs control of switching the input side switch and the output side switch to the bypass cable side when the detection level does not become lower than a certain level. May be adopted.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a circuit diagram showing an embodiment of the present invention. 2 is different from the conventional circuit of FIG. 2 in that switches SW1 and SW2 are provided in the input / output section, a bypass cable 15 is provided between the input and output, and the control signal a output from the control circuit 14 in the event of an abnormality is indicated by an abnormal signal. SW1 and SW2 are simultaneously switched to the bypass cable 15 side.
[0012]
Thus, in the abnormal time, since the amplification function is stopped, the level is reduced to the so that it is possible to use as an output signal, bypassing the input signal directly to the output side.
[0013]
The switching control circuit 16 does not need to be newly provided with the function of the control circuit 14.
[0014]
【The invention's effect】
As described above in detail, by carrying out the present invention, even if the operating distortion compensation amplifier fails and becomes abnormal, until fault recovery, levels may use the line be low it can.
In particular, if the gain of the distortion compensating amplifier is low, practically it is very effective because reduction of the output level by bypassing a small input signal becomes abnormal.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a conventional circuit block diagram.
[Explanation of symbols]
1, 4, 9 Directional coupler 2, 7 Vector adjuster 3 Main amplifier 5, 6 Delay line 8 Auxiliary amplifier 10 Amplifier 11 Pilot signal generator 12 Detector 13 Receiver 14 Control circuit 15 Bypass cable 16 Switching control circuit

Claims (2)

A distortion detection loop for detecting a distortion component based on a signal obtained by amplifying an input signal by a main amplifier via a first vector adjuster and an anti-phase signal via the first delay line; A distortion removal loop for canceling a distortion component by a signal amplified by an auxiliary amplifier through a second vector adjuster and a signal amplified by the main amplifier through a signal through a second delay line and outputting the resultant signal; The first vector adjuster and the second vector adjuster so that the detection level of the input signal extracted from the detection loop and the detection level of the pilot signal extracted from the distortion removal loop injected into the detection loop are minimized. A distortion compensation amplifier having a control circuit for adjusting the amount of attenuation and the amount of phase of the vector adjuster,
A bypass cable wired between an input terminal and an output terminal of the distortion compensation amplifier,
An input-side switch for switching and inputting the input signal to any one of the distortion compensation amplifier and the bypass cable;
An output-side switch that switches and outputs one of an output signal from the distortion compensation amplifier and an output signal from the bypass cable,
The control circuit monitors the detection level, and performs control to switch the input-side switch and the output-side switch to the bypass cable side when the detection level becomes larger than a predetermined threshold. A distortion compensation amplifier configured to perform. A distortion detection loop for detecting a distortion component based on a signal obtained by amplifying an input signal by a main amplifier via a first vector adjuster and an anti-phase signal via the first delay line; A distortion removal loop for canceling a distortion component by a signal amplified by an auxiliary amplifier through a second vector adjuster and a signal amplified by the main amplifier through a signal through a second delay line and outputting the resultant signal; The first vector adjuster and the second vector adjuster so that the detection level of the input signal extracted from the detection loop and the detection level of the pilot signal extracted from the distortion removal loop injected into the detection loop are minimized. A distortion compensation amplifier having a control circuit for adjusting the amount of attenuation and the amount of phase of the vector adjuster,
A bypass cable wired between an input terminal and an output terminal of the distortion compensation amplifier,
An input-side switch for switching and inputting the input signal to any one of the distortion compensation amplifier and the bypass cable;
An output-side switch that switches and outputs one of an output signal from the distortion compensation amplifier and an output signal from the bypass cable,
The control circuit monitors a detection level of the pilot signal, and performs control of switching the input side switch and the output side switch to the bypass cable side when the detection level does not become lower than a certain level. The distortion compensating amplifier configured in.

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