JPH07336154A - Feedforward amplifier - Google Patents
Feedforward amplifierInfo
- Publication number
- JPH07336154A JPH07336154A JP6153028A JP15302894A JPH07336154A JP H07336154 A JPH07336154 A JP H07336154A JP 6153028 A JP6153028 A JP 6153028A JP 15302894 A JP15302894 A JP 15302894A JP H07336154 A JPH07336154 A JP H07336154A
- Authority
- JP
- Japan
- Prior art keywords
- amplifier
- distortion
- signal
- delay line
- isolator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
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- Amplifiers (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、自動車電話等の移動通
信システムの基地局や中継装置などに用いられ、多周波
信号を同時に増幅する高線形増幅器の1種であるフィー
ドフォワード増幅器に関し、特に、その歪検出回路及び
歪除去回路の抑圧量の改善に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feedforward amplifier which is used as a base station or a repeater of a mobile communication system such as a car telephone and which is one of high linear amplifiers for simultaneously amplifying multi-frequency signals. , The improvement of the suppression amount of the distortion detection circuit and the distortion removal circuit.
【0002】[0002]
【従来の技術】800MHz帯の自動車電話システム等
における基地局及び無線中継装置には、多周波信号を同
時に増幅する多周波共通増幅器が設けられている。この
多周波共通増幅器は、相互変調歪を極力小さくするため
直線性を十分良くする必要があり、小形で高直線性増幅
器が用いられている。その一つとして、自己調整形フィ
ードフォワード増幅器(SAFF−A:Self−Ad
justing Feed−Forward Ampl
ifier)があり、主増幅器で発生する相互変調歪と
雑音を自己調整によって補償する共通増幅器である。こ
のフィードフォワード増幅器は、歪検出回路と歪除去回
路とから構成され、補償対象増幅器である主増幅器を含
む歪検出回路で入力信号以外の歪成分を検出し、検出さ
れた歪成分(誤差成分)を補助増幅器(誤差増幅器)を
含む歪除去回路に入力して歪成分を増幅した後、多周波
入力信号と逆相合成して歪成分の相殺を図るように構成
されている。2. Description of the Related Art A base station and a radio relay device in an 800 MHz band car telephone system or the like are provided with a multi-frequency common amplifier for simultaneously amplifying multi-frequency signals. This multi-frequency common amplifier is required to have sufficiently good linearity in order to reduce intermodulation distortion as much as possible, and a compact and highly linear amplifier is used. One of them is a self-adjusting feed forward amplifier (SAFF-A: Self-Ad).
Justing Feed-Forward Ampl
is a common amplifier that compensates for intermodulation distortion and noise generated in the main amplifier by self-adjustment. This feedforward amplifier is composed of a distortion detection circuit and a distortion removal circuit, detects a distortion component other than the input signal with a distortion detection circuit including a main amplifier that is an amplifier to be compensated, and detects the detected distortion component (error component). Is input to a distortion removal circuit including an auxiliary amplifier (error amplifier) to amplify the distortion component, and then is anti-phase combined with the multi-frequency input signal to cancel the distortion component.
【0003】図3は従来の自己調整形フィードフォワー
ド増幅器のブロック図である。図において、1は入力信
号を分配する電力分配器、2は可変減衰器、3は可変位
相器、4は主増幅器、5は遅延線路、7は電力合成器、
8は可変減衰器、9は可変位相器、10は補助増幅器、
11は遅延線路、13は電力合成器である。20は歪検
出回路、30は歪除去回路である。多周波入力信号は、
電力分配器1に入力され、2つに分岐された一方の多周
波信号は、可変減衰器2,可変位相器3を経て主増幅器
4で増幅される。その出力は増幅の際に発生する歪(誤
差)成分を含んでおり、電力合成器7の端子に入力さ
れ、電力分配器1で分岐出力され遅延線路5を経て電力
合成器7の端子に入力される多周波入力信号と逆相合
成されて端子から歪成分が検出される。電力合成器7
の端子から出力される多周波入力信号は、遅延線路1
1を経て電力合成器13の端子に入力される。電力合
成器7の端子から出力される歪成分は、可変減衰器
8,可変位相器9を経て補助増幅器10で増幅され電力
合成器13の端子に入力され、遅延線路11を経て入
力された歪成分を含む多周波信号と逆相合成されて歪成
分が相殺され、歪の少ない多周波増幅信号が電力合成器
13の端子から出力される。FIG. 3 is a block diagram of a conventional self-adjusting feedforward amplifier. In the figure, 1 is a power divider for distributing an input signal, 2 is a variable attenuator, 3 is a variable phase shifter, 4 is a main amplifier, 5 is a delay line, 7 is a power combiner,
8 is a variable attenuator, 9 is a variable phase shifter, 10 is an auxiliary amplifier,
Reference numeral 11 is a delay line, and 13 is a power combiner. Reference numeral 20 is a distortion detection circuit, and 30 is a distortion removal circuit. The multi-frequency input signal is
One multi-frequency signal input to the power distributor 1 and branched into two is amplified by the main amplifier 4 via the variable attenuator 2 and the variable phase shifter 3. The output includes a distortion (error) component generated at the time of amplification, is input to the terminal of the power combiner 7, is branched and output by the power distributor 1, and is input to the terminal of the power combiner 7 via the delay line 5. The distortion component is detected from the terminal after being subjected to reverse phase synthesis with the multi-frequency input signal. Power combiner 7
The multi-frequency input signal output from the terminal of
It is input to the terminal of the power combiner 13 via 1. The distortion component output from the terminal of the power combiner 7 is amplified by the auxiliary amplifier 10 via the variable attenuator 8 and the variable phase shifter 9, is input to the terminal of the power combiner 13, and is input via the delay line 11. The multi-frequency signal including the component is anti-phase combined to cancel the distortion component, and the multi-frequency amplified signal with less distortion is output from the terminal of the power combiner 13.
【0004】[0004]
【発明が解決しようとする課題】しかしながら、このよ
うな回路において、通常、主増幅器4及び補助増幅器1
0の帯域内振幅偏差特性は帯域の中心周波数に同調がと
られており、(a)および(d)のように、帯域の両端
部分のレベルが下がった特性になっている。一方、遅延
線路5及び11は、セミリジッドケーブルまたは同軸ケ
ーブルで実現されているので、帯域内偏差はほとんどな
く、(b)及び(c)のような平坦な特性になってい
る。そのため、歪検出回路20,歪除去回路30におい
て、基本波及び歪成分を相殺するための電力合成器7及
び11で合成する際、図4のように帯域の上限,下限付
近で特性の差があり、全帯域の振幅特性が一致しないた
め、帯域全体の歪抑圧量が一様でないという欠点があ
る。本発明の目的は、歪検出回路及び歪除去回路におけ
る上記帯域の両端部分の振幅偏差による歪抑圧量の低下
を改善するようにしたフィードフォワード増幅器を提供
することにある。However, in such a circuit, the main amplifier 4 and the auxiliary amplifier 1 are usually used.
The in-band amplitude deviation characteristic of 0 is tuned to the center frequency of the band, and has a characteristic in which the levels at both ends of the band are lowered as shown in (a) and (d). On the other hand, since the delay lines 5 and 11 are realized by a semi-rigid cable or a coaxial cable, they have almost no in-band deviation and have flat characteristics as shown in (b) and (c). Therefore, in the distortion detection circuit 20 and the distortion removal circuit 30, when the power combiners 7 and 11 for canceling the fundamental wave and the distortion component are combined, there is a difference in characteristics near the upper and lower limits of the band as shown in FIG. However, since the amplitude characteristics of all bands do not match, the amount of distortion suppression over the entire band is not uniform. It is an object of the present invention to provide a feedforward amplifier that improves the reduction in distortion suppression amount due to the amplitude deviation at both ends of the band in the distortion detection circuit and distortion removal circuit.
【0005】[0005]
【課題を解決するための手段】本発明のフィードフォワ
ード増幅器は、多周波入力信号を電力分配器で分岐出力
し、その一方の信号を第1の可変減衰器,第1の可変位
相器を介して主増幅器で増幅した信号と、他方の信号を
第1の遅延線路によってタイミングを合わした信号とを
第1の電力合成器で逆相合成することにより前記主増幅
器で発生した歪成分を検出する歪検出回路と、前記第1
の電力合成器から出力される前記歪成分を第2の可変減
衰器,第2の可変位相器を介して補助増幅器で増幅した
信号と、前記第1の電力合成器から出力される主増幅器
で増幅した信号を第2の遅延線路によってタイミングを
合わした信号とを第2の電力合成器で逆相合成すること
により前記主増幅器で発生した歪成分を相殺して多周波
増幅信号を出力する歪除去回路とを備えたフィードフォ
ワード増幅器において、前記主増幅器の振幅周波数特性
と近似した周波数特性を有し、前記第1の遅延線路と直
列に挿入接続した第1のアイソレータと、前記補助増幅
器の振幅周波数特性と近似した周波数特性を有し、前記
第2の遅延線路と直列に挿入接続した第2のアイソレー
タとを備えたことを特徴とするものであり、さらに、前
記第1のアイソレータおよび前記第2のアイソレータの
代わりに第1の増幅器および第2の増幅器を備えたこと
を特徴とするものである。A feedforward amplifier according to the present invention branches a multi-frequency input signal by a power divider and outputs one of the signals via a first variable attenuator and a first variable phase shifter. The signal amplified by the main amplifier and the signal whose other signal is timed by the first delay line are subjected to anti-phase combination by the first power combiner to detect the distortion component generated in the main amplifier. A distortion detection circuit, and the first
A signal obtained by amplifying the distortion component output from the power combiner of FIG. 2 by an auxiliary amplifier via a second variable attenuator and a second variable phase shifter, and a main amplifier output from the first power combiner. Distortion that cancels the distortion component generated in the main amplifier and outputs a multi-frequency amplified signal by subjecting the amplified signal and the signal whose timing is adjusted by the second delay line to each other in antiphase combination by the second power combiner. In a feedforward amplifier including a removal circuit, a first isolator that has a frequency characteristic similar to the amplitude frequency characteristic of the main amplifier, is inserted and connected in series with the first delay line, and the amplitude of the auxiliary amplifier. A second isolator having a frequency characteristic similar to that of the second delay line, the second isolator being inserted and connected in series with the second delay line; and the first isolator. It is characterized in that it comprises a first amplifier and the second amplifier instead of data and the second isolator.
【0006】[0006]
【実施例】図1は本発明の実施例を示すブロック図であ
る。図3に示した従来の構成と異なる点は、遅延線路
5,11にそれぞれアイソレータ6及び12を挿入した
点である。本発明の歪検出回路20,歪除去回路30に
おいて、広帯域の歪補償を改善するために、振幅偏差に
着目し、挿入するアイソレータ6,12の帯域内偏差
を、特性(g),(h)のように主増幅器4及び補助増
幅器10の周波数特性にそれぞれ相似させることによ
り、歪抑圧量を決定する要素である振幅,位相のうち、
振幅の項の偏差を少しでも補正することで歪補償量の改
善を図ったものである。FIG. 1 is a block diagram showing an embodiment of the present invention. The difference from the conventional configuration shown in FIG. 3 is that isolators 6 and 12 are inserted in the delay lines 5 and 11, respectively. In the distortion detection circuit 20 and the distortion removal circuit 30 of the present invention, attention is paid to the amplitude deviation in order to improve the distortion compensation in the wide band, and the in-band deviation of the inserted isolators 6 and 12 is represented by the characteristics (g) and (h). As described above, by making the frequency characteristics of the main amplifier 4 and the auxiliary amplifier 10 similar to each other, among the amplitude and the phase which are the factors that determine the distortion suppression amount,
This is intended to improve the amount of distortion compensation by correcting the deviation of the amplitude term as much as possible.
【0007】本発明の他の実施例として、アイソレータ
6,12の代わりに、図1に破線で示したように、アイ
ソレータと同様の周波数特性を有する増幅器を設けても
よい。さらに、逆方向損失の得られるアイソレータある
いは増幅器を設けることにより、可変減衰器2,8の制
御が不完全となったときでも、歪検出回路20の遅延線
5を逆流するループや、歪除去回路30の遅延線11を
逆流するループの異常発振が発生することはないので極
めて安定な共通増幅動作が維持される。As another embodiment of the present invention, instead of the isolators 6 and 12, an amplifier having a frequency characteristic similar to that of the isolator may be provided as shown by a broken line in FIG. Further, by providing an isolator or an amplifier that can obtain a reverse loss, even when the control of the variable attenuators 2 and 8 is incomplete, a loop that flows backward through the delay line 5 of the distortion detection circuit 20 and a distortion removal circuit. Since abnormal oscillation of the loop that flows backward through the delay line 11 of 30 does not occur, an extremely stable common amplification operation is maintained.
【0008】図2は位相偏差及び振幅偏差における信号
相殺量の改善説明図である。従来の振幅偏差が0.5d
B,位相差0°とすると、抑圧量は25dBであるが、
本発明によって振幅偏差を0.2dBとすることで、抑
圧量は32〜33dBとなり、約8dB程度改善される
ことがわかる。8dBの改善に伴い、補助増幅器11の
直線性の性能も向上することができ、経済的にも有利に
なることは明確である。図5はフィードフォワード増幅
器の振幅,位相不平衡度と信号抑圧量の特性例図であ
る。FIG. 2 is an explanatory diagram for improving the amount of signal cancellation in the phase deviation and the amplitude deviation. Conventional amplitude deviation is 0.5d
If the B and the phase difference are 0 °, the suppression amount is 25 dB,
According to the present invention, by setting the amplitude deviation to 0.2 dB, the suppression amount becomes 32 to 33 dB, which is improved by about 8 dB. With the improvement of 8 dB, it is clear that the linearity performance of the auxiliary amplifier 11 can be improved, which is economically advantageous. FIG. 5 is a characteristic example diagram of the amplitude, phase imbalance, and signal suppression amount of the feedforward amplifier.
【0009】[0009]
【発明の効果】以上詳細に説明したように、本発明を実
施することにより、フィードフォワード増幅器の歪補償
量が改善されるため、実用上極めて効果が大きい。As described in detail above, by implementing the present invention, the distortion compensation amount of the feedforward amplifier is improved, and therefore, the effect is extremely large in practical use.
【図1】本発明の実施例を示すブロック図である。FIG. 1 is a block diagram showing an embodiment of the present invention.
【図2】本発明の特性説明図である。FIG. 2 is a characteristic explanatory diagram of the present invention.
【図3】従来の増幅器のブロック図である。FIG. 3 is a block diagram of a conventional amplifier.
【図4】従来の特性説明図である。FIG. 4 is a conventional characteristic explanatory diagram.
【図5】フィードフォワード増幅器の特性例図である。FIG. 5 is a characteristic example diagram of a feedforward amplifier.
1 電力分配器 2,8 可変減衰器 3,9 可変位相器 4 主増幅器 5,11 遅延線路 6,12 アイソレータ 7,13 電力合成器 10 補助増幅器 20 歪検出回路 30 歪除去回路 1 Power Divider 2,8 Variable Attenuator 3,9 Variable Phaser 4 Main Amplifier 5,11 Delay Line 6,12 Isolator 7,13 Power Combiner 10 Auxiliary Amplifier 20 Distortion Detection Circuit 30 Distortion Removal Circuit
フロントページの続き (72)発明者 加賀屋 範行 東京都中野区東中野三丁目14番20号 国際 電気株式会社内Front page continuation (72) Inventor Noriyuki Kagaya 3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Kokusai Electric Co., Ltd.
Claims (2)
し、その一方の信号を第1の可変減衰器,第1の可変位
相器を介して主増幅器で増幅した信号と、他方の信号を
第1の遅延線路によってタイミングを合わした信号とを
第1の電力合成器で逆相合成することにより前記主増幅
器で発生した歪成分を検出する歪検出回路と、 前記第1の電力合成器から出力される前記歪成分を第2
の可変減衰器,第2の可変位相器を介して補助増幅器で
増幅した信号と、前記第1の電力合成器から出力される
主増幅器で増幅した信号を第2の遅延線路によってタイ
ミングを合わした信号とを第2の電力合成器で逆相合成
することにより前記主増幅器で発生した歪成分を相殺し
て多周波増幅信号を出力する歪除去回路と、 を備えたフィードフォワード増幅器において、 前記主増幅器の振幅周波数特性と近似した周波数特性を
有し、前記第1の遅延線路と直列に挿入接続した第1の
アイソレータと、 前記補助増幅器の振幅周波数特性と近似した周波数特性
を有し、前記第2の遅延線路と直列に挿入接続した第2
のアイソレータとを備えたことを特徴とするフィードフ
ォワード増幅器。1. A signal obtained by branching and outputting a multi-frequency input signal by a power divider, one signal of which is amplified by a main amplifier via a first variable attenuator and a first variable phase shifter, and the other signal. A distortion detection circuit for detecting a distortion component generated in the main amplifier by performing a reverse phase combination of a signal whose timing is adjusted by a first delay line with a first power combiner, and the first power combiner. The distortion component output from the second
, The signal amplified by the auxiliary amplifier via the variable attenuator and the second variable phase shifter, and the signal amplified by the main amplifier output from the first power combiner are timed by the second delay line. A feed-forward amplifier comprising: a distortion removing circuit for canceling a distortion component generated in the main amplifier by outputting a multi-frequency amplified signal by performing anti-phase combination with a signal in a second power combiner; A first isolator having a frequency characteristic close to the amplitude frequency characteristic of the amplifier, inserted and connected in series with the first delay line; and a frequency characteristic close to the amplitude frequency characteristic of the auxiliary amplifier, The second, which is inserted and connected in series with the second delay line
And a feed-forward amplifier.
のアイソレータの代わりにそれぞれ同等の周波数特性を
有する第1の増幅器および第2の増幅器を備えたことを
特徴とする請求項1記載のフィードフォワード増幅器。2. The first isolator and the second isolator
2. The feedforward amplifier according to claim 1, further comprising a first amplifier and a second amplifier each having an equivalent frequency characteristic instead of the isolator.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15302894A JP3400113B2 (en) | 1994-06-13 | 1994-06-13 | Feedforward amplifier |
JP2000175296A JP3494957B2 (en) | 1994-06-13 | 2000-06-12 | Feedforward amplifier |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15302894A JP3400113B2 (en) | 1994-06-13 | 1994-06-13 | Feedforward amplifier |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2000175296A Division JP3494957B2 (en) | 1994-06-13 | 2000-06-12 | Feedforward amplifier |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH07336154A true JPH07336154A (en) | 1995-12-22 |
JP3400113B2 JP3400113B2 (en) | 2003-04-28 |
Family
ID=15553394
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP15302894A Expired - Fee Related JP3400113B2 (en) | 1994-06-13 | 1994-06-13 | Feedforward amplifier |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3400113B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09270642A (en) * | 1996-04-02 | 1997-10-14 | Kokusai Electric Co Ltd | Broad band distortion compensation amplifier |
-
1994
- 1994-06-13 JP JP15302894A patent/JP3400113B2/en not_active Expired - Fee Related
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09270642A (en) * | 1996-04-02 | 1997-10-14 | Kokusai Electric Co Ltd | Broad band distortion compensation amplifier |
Also Published As
Publication number | Publication date |
---|---|
JP3400113B2 (en) | 2003-04-28 |
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