JPS63232530A - Amplification distortion compensating and controlling system - Google Patents

Abstract

PURPOSE:To attain the control of the compensation of distortion which is resistant to the alteration of an actuating condition, etc., by adding the alteration reflected quantity of the actuating condition, etc., to the control of the compensation of distortion. CONSTITUTION:As for the distortion component caused to an output signal in an amplifier 10 at the time of amplifying in the amplifier 10, a distortion compensator 4 gives the component in relation of an opposite phase to an input signal and outputs it to the amplifier 10 and consists of a distortion generating unit 7, a variable phase shifter 8 and a variable gain unit 9. The control by a control part 14 to the variable phase shifter 8 and the variable gain unit 9 is executed on the condition that a relative value between a signal level and a distortion level detected from a branch output signal from the amplifier 10 by a distortion level detector 13 and a signal level detector 30 is made smaller than a previously specified value. Thus, the stable compensation of distortion can be executed to the fine variation of the signal component by the alteration of the actuating condition, etc.

Description

[Detailed Description of the Invention] [Summary] In distortion compensation control when the amplifier is used in the same manner as in its linear region while compensating for the distortion of the amplifier, it is possible to In addition to distortion compensation control, distortion compensation control that is resistant to changes in operating conditions etc. is performed.

[Industrial application field]

The present invention relates to an amplification distortion compensation control system, and more specifically, to an amplification distortion compensation control system that can compensate for distortion of an amplifier as specified even when operating conditions change.

In the SSB-AM method and multilevel QAM method used in wireless communication systems, amplitude modulation is applied to the modulated signal, so when the signal is amplified by a transmission power amplifier, it is necessary to prevent nonlinear distortion from appearing in the output. I have to try.

To achieve this, it is possible to meet this requirement by using an amplifier with a very high saturation output level that can provide a wide linear region, but this also increases the power consumption of the amplifier, so in recent years Techniques have been developed and put into practical use that provide distortion compensation control to amplifiers with relatively low output levels, allowing them to perform the same amplification function as amplifiers with very high saturated output levels. It's coming.

[Conventional technology]

An example of a high power amplifier configuration of the type described above is shown in FIG. In this configuration example, the main part of the amplification function described above is to prevent distortion of the amplifier from being introduced into the amplified signal by giving the sufficient amount given to the amplifier 10 during amplification to the input side in reverse phase. , To that end, (1) the distortion generator 7 applies distortion to the uncompensated input signal branched at the distributor 5;
A variable phase shifter 8 and a variable attenuator 9 are applied to the output signal.
gives the necessary phase and amplitude control to generate distortion cancellation,
This distortion-cancelled signal is combined with the uncompensated input signal from the distributor 5 in the combiner 6 and is input to the amplifier 2NO. The control system for the variable phase shifter 8 and the variable attenuator 9 for generating the distortion canceling signal includes a splitter 11 provided on the output side of the amplifier 10, a frequency converter 12, a distortion level detector 13, and a control section. It consists of 14 parts. The distortion level detector 13 (see FIG. 5(B)) includes a band-elimination filter (BEF) 15, a low-noise amplifier (AMP) 16, a distributor (HYB) 17, and a band-pass filter (BPF) 18.2.
2, Amplifier (AMP) 19, 23, Detector (DET) 2
0.24 and a DC amplifier (DCAMP) 21.25, whose bandpass filter 18, amplifier 19, detector 20 and DC amplifier 21 output a distortion component voltage signal VFL on the low side of the signal band. Then, the bandpass filter 22, the amplifier 23, the detector 24, and the DC amplifier 25 output a distortion component voltage signal VFH on the high-frequency side of the signal band.

Then, the control unit 14 (see FIG. 5(B)) receives each distortion component voltage signal F L r V from the distortion level detector 13.
The analog-to-digital converter 26 receives y
, a ROM 29 storing a program for generating ΔG, such as the one shown in the flowchart of FIG. It consists of a digital-to-analog converter 28 that converts lff1 into an analog signal. Note that 12 is a frequency converter, 2 is a local oscillator, and 3 is a distributor.

The manner of controlling the phase and amplitude by this control system for the third-order intermodulation component (1M3) shown in the control flow of FIG. 6 can be summarized as follows.

The 1M3 distortion component level VFL+VFR (6th
100) in the figure is a predetermined reference value ■□.

(102 in Fig. 6), first perform control to minimize the distortion component level VFL so that the distortion component level ■FL, VF) I becomes less than the reference value ■□. 104 to 110), and the distortion component level VF□ decreases, and control is performed to minimize 1v□-VFLI (112 to 118 in FIG. 6), and both distortion component levels vFL, V
FH is the standard V l! When the temperature falls below F, the control is stopped. Note that the above two distortion component levels are used for control as follows:
Imperfection of distortion compensation in the distortion compensation control system including the amplifier, that is, even if the level of one distortion component is lowered below the reference value,
This is due to the fact that the level of one distortion component does not necessarily fall below the reference value.

[Problem that the invention seeks to solve]

The reference value used in the above-mentioned distortion compensation control is a value consisting of the signal level under predetermined operating conditions of the amplifier including the above-mentioned distortion compensation system, for example, a value at which the signal level has decreased by 50 dB, which is an extremely small value. The distortion compensation method performs distortion compensation control under conditions that remain fixed at the above-determined values even if the operating conditions change.

However, ideally, the reference value must be set in accordance with operating conditions such as temperature changes and fluctuations in power supply voltage. Therefore, when the transmission output level or the like changes due to a change in operating conditions, the reference value deviates from a value corresponding to the change, and the more the degree of deviation progresses, the larger the error becomes.

Therefore, it becomes impossible to accurately detect the distortion level, and an error occurs in distortion compensation control. This is extremely serious as it will impede normal commuting.

The present invention was created in view of such problems, and it is an object of the present invention to provide an amplification distortion compensation control method that can perform stable control against minute fluctuations in signal components caused by operating conditions, etc. That purpose.

[Means for solving problems]

FIG. 1 is a diagram showing the principle configuration of the present invention. In this diagram,
Reference numeral 10 denotes an amplifier that amplifies the distortion-compensated input signal from the distortion compensator 4. , the distortion compensator 4 provides the input signal with a component that has an opposite phase relationship with respect to the distortion component produced in the output signal by the amplifier 10 when it is amplified by the amplifier 10, and outputs it to the amplifier lO, It consists of a distortion generator 7, a variable phase shifter 8, and a variable gain unit 9. The control unit 14 controls the variable phase shifter 8 and the variable gain 9 by using a relative value between the distortion level and signal level detected by the distortion level detector 13 and the signal level detector 30 from the branch output signal of the amplifier 10. The present invention is characterized in that it is multiplied on the condition that the value becomes smaller by a predetermined value.

[For production]

The phase and amplitude of the distortion canceling signal that is synthesized with the input signal is controlled by predetermining the relative values of each detection level output from the distortion level detector 13 and the signal level detector 14 as the operating conditions change. Occurs when the value falls below the specified value.

In other words, whereas conventionally the reference value that was fixed for the signal level in a predetermined state was used as the basis for starting the above-mentioned control, the relative value between the signal level and the distortion level was used as the basis for starting the control. I decided to set the standards for

Therefore, stable distortion compensation can be performed for minute fluctuations in signal components due to changes in operating conditions and the like.

〔Example〕

FIG. 2 shows an embodiment of the invention. In this embodiment, a signal level detector 30 is provided in the configuration of the amplification distortion compensation control method shown in FIG.
In response to the detection output of step 3, the control unit 14 performs control according to the control flow shown in FIG. 4 to obtain the phase control amount Δφ and the amplitude control amount Δ.
It is configured to generate G. The signal level detector 30, as shown in FIG.
4. Detector (DET) 35 and DC amplifier (DCAMP)
) consists of 36. Since the other components are the same as those in FIG. 5, the same reference numerals are given to these components and the explanation thereof will be omitted.

By providing the features of the present invention configured as described above, reliable control can be performed against changes in the operating conditions of the amplification distortion compensation control system including the amplifier IO.

That is, if this control is explained according to the control flow in FIG. 4, it will be as follows. The control flow in FIG. 4 is for the third-order intermodulation component (1M3) which accounts for most of the distortion.

When the control is entered (94 in FIG. 4), data initialization is performed (96 in FIG. 4), and level improvement of 1M3 begins. The process up to this point is the same as before.

Then, the output of the distortion level detector 13, that is, the DC amplifier 2
The distortion component level VFL from 1, the distortion component level ■□ from the DC amplifier 25, and the output of the signal level detector 30, that is, the signal levels v and l from the DC amplifier 36 are input to the analog-digital converter 26 of the control unit 14. is converted into a digital value and output. Those digital values are stored in the CPU
27 (120 in FIG. 4). And lv
l, 1-VFLI, and IVM VFHI are determined (122 in FIG. 4), and it is determined whether one of these two values is smaller than a predetermined reference value V□2 ( 124 in Figure 4).

If the determination is negative, the distortion component level vFL.

■□ is at a level that does not require distortion compensation control, and the process returns to step 120 to continue monitoring the distortion level.

If the determination is affirmative, that is, if the distortion component level VFL+ ■FH has increased to a level that requires distortion compensation control, control is entered in steps 104 to 118, and phase control is performed until the above determination becomes negative. The value Δφ and the amplitude control value ΔG are adjusted. These steps are the same as conventional control steps and a detailed explanation thereof is deemed unnecessary and will not be repeated.

As mentioned above, in distortion compensation control, the activation criterion is based on the relative value between the signal level and the distortion level, that is, the control is performed taking into account changes in operating conditions, etc. It is possible to perform strong amplification distortion compensation control against such changes.

In the above embodiment, an example was shown in which IF times signal frequency conversion was performed, but the present invention can be equally applied to a case where such conversion is not required.

〔Effect of the invention〕

As described above, according to the present invention, the activation of amplification distortion compensation control is related to the relative value between the signal level and the distortion level, so that stable amplification distortion compensation control can be performed even in response to minute fluctuations in signal components. can be done.

[Brief explanation of drawings]

Figure 1 is a diagram showing the principle configuration of the present invention, Figure 2 is a diagram showing an embodiment of the present invention, Figure 3 is a detailed diagram of the main parts of the control system in Figure 2, and Figure 4 is a diagram showing the control flow of the present invention. FIG. 5 is a block diagram of a conventional amplification distortion compensation control system, and FIG. 6 is a diagram showing a conventional control flow. 1 and 2, 4 is a distortion compensator, 8.9 is a distortion compensation control section, IO is an amplifier, 13 is a distortion level detector, 14 is a control section, and 30 is a signal level detector. Figure 1 of Sairi's asshole in Kimi's eyes) (B) The power is also a plan to depict the middle of the day, and the struggle is poor.

Claims (1)

[Claims] A distortion compensation input signal from a distortion compensation control section (8, 9) whose phase and amplitude are controlled by a control section (14) responsive to the amplified branch output and an uncompensated input signal are combined. In an amplifier that amplifies a signal obtained by amplification, the control section (14) includes a signal level detector (30) that detects a signal level from the amplified branch output, and a distortion detector that detects a distortion level from the amplified branch output. a level detector (13), and controls the phase and amplitude when a relative value between the signal level and the distortion level becomes smaller than a predetermined value. Distortion compensation control method.