JP2002271149A - Feed-forward distortion compensating amplifier - Google Patents
Feed-forward distortion compensating amplifierInfo
- Publication number
- JP2002271149A JP2002271149A JP2001071547A JP2001071547A JP2002271149A JP 2002271149 A JP2002271149 A JP 2002271149A JP 2001071547 A JP2001071547 A JP 2001071547A JP 2001071547 A JP2001071547 A JP 2001071547A JP 2002271149 A JP2002271149 A JP 2002271149A
- Authority
- JP
- Japan
- Prior art keywords
- distortion
- delay
- level
- amplifier
- control voltage
- 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.)
- Pending
Links
Landscapes
- Amplifiers (AREA)
- Transmitters (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、移動通信システム
における無線基地局に設備される無線送受信装置の送信
部に用いられる送信電力増幅装置の一種であるフィード
フォワード歪補償増幅器に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed-forward distortion compensating amplifier, which is a kind of transmission power amplifying device used for a transmitting section of a radio transmitting / receiving device provided in a radio base station in a mobile communication system.
【０００２】[0002]
【従来の技術】フィードフォワード歪補償増幅器は、複
数の搬送波を増幅する際に、増幅器の非線形特性のため
に生ずる相互変調波歪を自己調整によって補償する装置
である。2. Description of the Related Art A feed-forward distortion compensating amplifier is a device for self-adjusting intermodulation wave distortion caused by nonlinear characteristics of an amplifier when a plurality of carriers are amplified.
【０００３】図３は従来のフィードフォワード歪補償増
幅器の回路構成例図である。図において、１は分配器、
２はベクトル調整器、３は主増幅器、４は方向性結合
器、５は遅延線、６はベクトル調整器、７は補助増幅
器、８は方向性結合器、９は遅延線、１０は制御回路で
ある。分配器１から方向性結合器４までを歪検出ループ
といい、方向性結合器４から８までを歪除去ループとい
う。FIG. 3 is a diagram showing an example of a circuit configuration of a conventional feedforward distortion compensation amplifier. In the figure, 1 is a distributor,
2 is a vector adjuster, 3 is a main amplifier, 4 is a directional coupler, 5 is a delay line, 6 is a vector adjuster, 7 is an auxiliary amplifier, 8 is a directional coupler, 9 is a delay line, and 10 is a control circuit. It is. The portion from the distributor 1 to the directional coupler 4 is called a distortion detection loop, and the portion from the directional couplers 4 to 8 is called a distortion removal loop.
【０００４】所定の振幅に調整された送信入力は分配器
１で２つに分配され、一方の主信号はベクトル調整器２
を経て主増幅器３で増幅される。このとき主増幅器３の
非線形特性のため相互変調歪が発生し、その歪を含んだ
主増幅信号が方向性結合器４に入力される。一方、送信
入力は遅延線５によって主増幅器側と遅延時間が同じく
なるように遅延させられて方向性結合器４に逆相で入力
され、ベクトル調整器２で振幅と位相が調整された主増
幅信号と合成され、送信信号成分が相殺された歪成分が
補助増幅器側に出力され、遅延線側には歪を含んだ増幅
信号が出力される。A transmission input adjusted to a predetermined amplitude is split into two by a splitter 1, and one main signal is sent to a vector adjuster 2
, And is amplified by the main amplifier 3. At this time, intermodulation distortion occurs due to the non-linear characteristics of the main amplifier 3, and a main amplified signal including the distortion is input to the directional coupler 4. On the other hand, the transmission input is delayed by the delay line 5 so that the delay time is the same as that of the main amplifier, input to the directional coupler 4 in the opposite phase, and the main amplifier whose amplitude and phase are adjusted by the vector adjuster 2. A distortion component that is combined with the signal and the transmission signal component of which is canceled is output to the auxiliary amplifier side, and an amplified signal containing distortion is output to the delay line side.
【０００５】上記の検出ループで検出された歪成分はベ
クトル調整器６を経て補助増幅器７で増幅されて方向性
結合器８に入力される。一方、歪を含んだ主増幅信号は
遅延線９によって補助増幅器側の遅延時間と同じ遅延時
間が与えられて方向性結合器８に入力されて逆相に合成
され、歪の少ない送信信号が出力される。この際、歪成
分の相殺量が小さくなるようにベクトル調整器６で歪成
分の振幅と位相が調整される。The distortion component detected by the above detection loop is amplified by an auxiliary amplifier 7 via a vector adjuster 6 and input to a directional coupler 8. On the other hand, the main amplified signal including the distortion is given the same delay time as the delay time on the auxiliary amplifier side by the delay line 9, is input to the directional coupler 8, and is synthesized in the opposite phase, and the transmission signal with less distortion is output. Is done. At this time, the amplitude and phase of the distortion component are adjusted by the vector adjuster 6 so that the amount of cancellation of the distortion component is reduced.
【０００６】[0006]
【発明が解決しようとする課題】上記従来のフィードフ
ォワード歪補償増幅器では遅延線５は固定であり、歪検
出ループで検出する歪成分をできるだけ真値に近づける
ため、主増幅器側のベクトル調整器２の振幅と位相を調
整し、遅延線側の位相と逆相となるようにしている。し
かし、ベクトル調整器２を調整するだけでは十分ではな
く、止むを得ず、例えば、遅延線５を長めに加工してお
き、調整時に切断するなど、手加工で遅延線の遅延量を
微調整する作業が行われていた。そのため、調整作業に
時間がかかり、作業の熟練度も要求されて原価の増加を
生ずるという問題があった。In the conventional feedforward distortion compensating amplifier described above, the delay line 5 is fixed, and in order to make the distortion component detected by the distortion detection loop as close as possible to the true value, the vector adjuster 2 on the main amplifier side is used. Is adjusted so that the phase is opposite to the phase on the delay line side. However, simply adjusting the vector adjuster 2 is not enough, and it is unavoidable. For example, the delay line 5 is processed to be longer, and the delay amount of the delay line is finely adjusted by manual processing, such as cutting during adjustment. Work was being done. For this reason, there is a problem in that it takes a long time for the adjustment work, the skill of the work is required, and the cost is increased.
【０００７】本発明は、上記従来の問題点を解消するた
めに行ったものであり、作業者の調整作業がなくなり、
従って、熟練作業も不要で、しかも、自動的に歪検出量
を真値に近づけることができるようにしたフィードフォ
ワード歪補償増幅器を提供することを目的とする。The present invention has been made to solve the above-mentioned conventional problems, and eliminates the need for an operator to perform adjustment work.
Accordingly, it is an object of the present invention to provide a feedforward distortion compensating amplifier that does not require any skilled work, and that can automatically bring the distortion detection amount close to a true value.
【０００８】[0008]
【課題を解決するための手段】本発明のフィードフォワ
ード歪補償増幅器は、入力信号を分配器で分岐出力し、
その一方の信号を第１のベクトル調整器を介して主増幅
器で増幅した主増幅信号と他方の信号を第１の遅延手段
によって遅延させた信号とを第１の方向性結合器で逆相
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
出する歪検出ループと、前記歪検出ループで検出された
前記歪成分を第２のベクトル調整器を介して補助増幅器
で増幅した信号と前記主増幅信号を第２の遅延手段によ
って遅延させた信号とを第２の方向性結合器で逆相合成
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
て送信信号を出力する歪除去ループとを備えたフィード
フォワード歪補償増幅器であって、前記第１の遅延手段
は、固定遅延線と該固定遅延線に直列に接続され切替え
制御電圧によって少なくとも２つの相異なる遅延時間の
微調整用遅延線が選択接続される可変遅延器とで構成さ
れ、前記歪検出ループから検出される前記歪成分のレベ
ルを監視して前記可変遅延器の微調整用遅延線を切替え
制御する制御手段が設けられ、前記制御手段は、前記歪
成分のレベルが所定の許容値以上のとき前記切替え制御
電圧を変えて前記微調整用遅延線を切替え接続し歪成分
のレベルが小さくなれば更に制御電圧を変えて前記許容
値以下になるまで切替え制御し、前記微調整用遅延線を
切替え接続して歪成分のレベルが大きくなったときは制
御電圧を逆の方向に変えて歪成分のレベルが小さくなれ
ば更に制御電圧を変えて前記許容値以下になるまで切替
え制御するように構成されたことを特徴とするものであ
る。A feedforward distortion compensating amplifier according to the present invention branches and outputs an input signal with a distributor.
A first directional coupler combines the main amplified signal obtained by amplifying one of the signals through the first vector adjuster with the main amplifier and the signal obtained by delaying the other signal by the first delay means, in a first directional coupler. A distortion detection loop for detecting a distortion component generated in the main amplifier, a signal obtained by amplifying the distortion component detected in the distortion detection loop by an auxiliary amplifier via a second vector adjuster, and A second directional coupler that combines the signal delayed by the second delay means and the signal delayed by the second directional coupler to cancel a distortion component generated in the main amplifier and output a transmission signal; A feed-forward distortion compensating amplifier comprising: a fixed delay line and a delay line for fine adjustment of at least two different delay times which are connected in series with the fixed delay line and are controlled by a switching control voltage. Control means configured to selectively control a delay line for fine adjustment of the variable delay device by monitoring a level of the distortion component detected from the distortion detection loop, When the level of the distortion component is equal to or greater than a predetermined allowable value, the control means changes the switching control voltage to switch and connect the fine adjustment delay line. When the level of the distortion component is increased by switching and connecting the fine adjustment delay line, the control voltage is changed in the opposite direction, and the control voltage is further reduced when the level of the distortion component is reduced. And the switching control is performed until the value becomes equal to or less than the allowable value.
【０００９】[0009]
【発明の実施の形態】図１は本発明の実施例を示す回路
構成図である。従来の構成と同じ部分には同符号を付し
た。本発明では、従来の固定遅延線５の代わりに、可変
遅延器５０を設け、方向性結合器４から出力される歪成
分を抽出してフィルタ１１を通し、検波器１２で検波し
てＡ／Ｄ変換器１３でディジタル変換し、マイクロプロ
セッサなどの制御器１４で制御データを算出し、そのデ
ィジタル値をＤ／Ａ変換器１５でアナログ変換して可変
遅延器５０の遅延量を制御するように構成したことを特
徴とするものである。FIG. 1 is a circuit diagram showing an embodiment of the present invention. The same parts as those in the conventional configuration are denoted by the same reference numerals. In the present invention, a variable delay device 50 is provided in place of the conventional fixed delay line 5, a distortion component output from the directional coupler 4 is extracted, passed through the filter 11, detected by the detector 12, and A / A The D / A converter 13 performs digital conversion, the control data such as a microprocessor calculates control data, and the D / A converter 15 converts the digital value into analog data to control the delay amount of the variable delay device 50. It is characterized by having comprised.
【００１０】可変遅延器５０は、固定長の遅延線Ｄ
0 と、互いに異なった長さ（遅延時間）の微調用遅延線
Ｄ1 ，Ｄ2 ，Ｄ3 と、そのいずれかを切替える切替器５
１とから構成され、切替制御電圧ＶP によって選択され
た遅延線と固定長の遅延線Ｄ0 が直列に接続されて分配
器１と方向性結合器４の間に接続される。The variable delay unit 50 has a fixed length delay line D
0 , fine adjustment delay lines D 1 , D 2 , D 3 having different lengths (delay times), and a switch 5 for switching any of them
Consists Tokyo and delay line D 0 of fixed length is connected between the connected in series distributor 1 and the directional coupler 4 and the delay line selected by the switching control voltage V P.
【００１１】図２は本発明の遅延量補正手段の制御動作
を示すフローチャートであり、〜はステップ番号で
ある。本発明による遅延量の調整量は、前述のように微
調整の段階なので、予め、歪成分のレベルのしきい値が
設定され、しきい値以上、すなわち歪成分が許容値以上
のとき遅延量を微調するものである。遅延量の変化にと
もなって位相が変化するので、例えば、位相が進むと遅
延量は減るので、その特性を活かしてベクトル調整器２
の位相調整を補うものである。FIG. 2 is a flowchart showing the control operation of the delay amount correcting means according to the present invention, where 〜 is a step number. Since the adjustment amount of the delay amount according to the present invention is a fine adjustment stage as described above, a threshold value of the level of the distortion component is set in advance, and the delay amount is equal to or more than the threshold value, that is, when the distortion component is equal to or more than the allowable value. Is to fine-tune. Since the phase changes with a change in the amount of delay, for example, the amount of delay decreases as the phase advances.
Of the phase adjustment.
【００１２】図２において、ステップで、制御器１４
は、方向性結合器４の出力側から抽出し、検波してディ
ジタル変換した歪成分のディジタル値が許容値以上か否
かを監視する。歪成分が許容値を超えたとき制御器１４
は可変遅延器５０の切替器５１の切替制御電圧ＶP を、
例えば、高くするように変える（ステップ）。その結
果、歪が小さくなれば（ステップ）歪が許容値以下に
なるまで電圧ＶP を高くする（ステップ）。そして許
容値以下になれば制御は終了してその遅延量に設定され
る。Referring to FIG. 2, the controller 14
Monitors whether the digital value of the distortion component extracted from the output side of the directional coupler 4 and detected and digitally converted is equal to or larger than an allowable value. When the distortion component exceeds the allowable value, the controller 14
The switching control voltage V P of the switch 51 of the variable delay unit 50,
For example, it is changed to be higher (step). As a result, when the distortion is reduced (step), the voltage VP is increased until the distortion becomes equal to or less than the allowable value (step). Then, if it becomes equal to or less than the allowable value, the control is terminated and the delay amount is set.
【００１３】ステップで歪が逆に大きくなったとき
は、ステップに移って電圧の変える方向を逆にする指
示を出す。ステップでは、その指示により、電圧ＶP
の変化を逆に、例えば、低くするように変化させる。以
下同様の制御を行って歪が許容値以下になるように制御
して終了する。When the distortion is increased in the step, the process proceeds to the step and an instruction is issued to reverse the direction in which the voltage is changed. In the step, according to the instruction, the voltage V P
Is changed to be lower, for example. Thereafter, the same control is performed so that the distortion becomes equal to or less than the allowable value, and the process is terminated.
【００１４】図１の可変遅延器５０の微調用遅延線
Ｄ1 ，Ｄ2 ，Ｄ3 の数は３個に限定するものではなく、
少なくとも遅延量が２通り以上に調整できればよい。そ
して、各遅延線の遅延時間（長さ）も実状に合わせて設
定すればよい。また、切替器５１は、電子スイッチ等任
意に選定すればよく、複数遅延線の片側を共通接続して
他方の端部のみ切替える構成でもよい。The number of fine adjustment delay lines D 1 , D 2 , D 3 of the variable delay device 50 shown in FIG. 1 is not limited to three.
It is sufficient that the delay amount can be adjusted to at least two types. Then, the delay time (length) of each delay line may be set according to the actual situation. Further, the switch 51 may be arbitrarily selected, such as an electronic switch, and may have a configuration in which one side of a plurality of delay lines is connected in common and only the other end is switched.
【００１５】図４は本発明と従来の動作説明図であり、
主増幅器の入出力位相差の周波数特性例を示す。（Ａ）
は従来の構成の場合を示し、（Ｂ）は本発明の場合を示
す。一般に増幅器やフィルタ等の４端子回路網におい
て、振幅特性が平坦な部分は位相は変化しないが、振幅
特性が傾斜する帯域の両側付近では位相が変化する。FIG. 4 is a diagram for explaining the operation of the present invention and the prior art.
4 shows an example of a frequency characteristic of an input / output phase difference of a main amplifier. (A)
Shows the case of the conventional configuration, and (B) shows the case of the present invention. Generally, in a four-terminal network such as an amplifier or a filter, the phase does not change in a portion where the amplitude characteristic is flat, but the phase changes near both sides of a band where the amplitude characteristic is inclined.
【００１６】図４（Ａ）において、主増幅器にその帯域
の中央付近の２つの搬送波ｆA1とｆ A2を入力したとき
は、２波の位相差は殆どない。しかし、互いに帯域の両
側の搬送波ｆB1とｆB2が入力されると２波の位相差は大
きく、従来の回路では遅延量の手作業による調整が必要
になる。図４（Ｂ）はこのような場合の本発明の効果を
示すものであり、帯域の両側の搬送波ｆB1とｆB2の位相
差が特性（イ）のように大きいとき、本発明によって自
動的に微調整が行われ特性（ロ）のようになる。In FIG. 4 (A), the main amplifier
Two carriers f near the center ofA1And f A2When you enter
Has almost no phase difference between the two waves. However, both bands
Side carrier fB1And fB2Input, the phase difference between the two waves is large.
Critical, conventional circuits require manual adjustment of delay
become. FIG. 4B shows the effect of the present invention in such a case.
And carrier f on both sides of the bandB1And fB2Phase of
When the difference is large as shown in the characteristic (a), the present invention
Fine adjustment is performed dynamically, and the characteristic (b) is obtained.
【００１７】[0017]
【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、歪検出ループの歪検出が不足の場合
でも自動的に遅延時間が微調整されて、歪レベルが最小
になるように制御され、結果的にフィードフォワード歪
補償振幅器の歪補償精度を向上することができる。さら
に、従来の手作業による遅延線の微調整が不要になり、
原価の上昇を抑えることができるという実用上極めて大
きな効果がある。As described in detail above, by implementing the present invention, even when the distortion detection of the distortion detection loop is insufficient, the delay time is automatically fine-tuned to minimize the distortion level. As a result, it is possible to improve the distortion compensation accuracy of the feedforward distortion compensation amplitude device. Furthermore, the conventional fine adjustment of the delay line by hand becomes unnecessary,
This has an extremely large practical effect that the rise in cost can be suppressed.
【図１】本発明の実施例を示す回路構成図である。FIG. 1 is a circuit diagram showing an embodiment of the present invention.
【図２】本発明の制御動作を示すフローチャートであ
る。FIG. 2 is a flowchart showing a control operation of the present invention.
【図３】従来の回路構成例図である。FIG. 3 is a diagram showing a conventional circuit configuration example.
【図４】本発明の効果を説明する特性例図である。FIG. 4 is a characteristic example illustrating the effect of the present invention.
１ 分配器 ２，６ ベクトル調整器 ３ 主増幅器 ４，８ 方向性結合器 ５，９ 遅延線 ７ 補助増幅器 １０ 制御回路 １１ フィルタ １２ 検波器 １３ Ａ／Ｄ変換器 １４ 制御器 １５ Ｄ／Ａ変換器 ５０ 可変遅延器 ５１ 切替器 Ｄ0 ，Ｄ1 ，Ｄ2 ，Ｄ3 遅延線DESCRIPTION OF SYMBOLS 1 Divider 2, 6 Vector adjuster 3 Main amplifier 4, 8 Directional coupler 5, 9 Delay line 7 Auxiliary amplifier 10 Control circuit 11 Filter 12 Detector 13 A / D converter 14 Controller 15 D / A converter Reference Signs List 50 variable delay device 51 switch D 0 , D 1 , D 2 , D 3 delay line
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 5J090 AA01 AA41 AA51 CA21 FA18 GN02 GN05 HA38 HN08 HN15 HN16 KA15 KA34 KA41 KA55 KA68 MA14 SA14 TA01 TA03 TA07 5J091 AA01 AA41 AA51 CA21 FA18 HA38 KA15 KA34 KA41 KA55 KA68 MA14 SA14 TA01 TA03 TA07 5K060 BB07 CC04 DD04 HH06 HH34 HH39 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J090 AA01 AA41 AA51 CA21 FA18 GN02 GN05 HA38 HN08 HN15 HN16 KA15 KA34 KA41 KA55 KA68 MA14 SA14 TA01 TA03 TA07 5J091 AA01 AA41 AA51 CA21 FA18 HA38 KA15 KA14 KA34 TA07 5K060 BB07 CC04 DD04 HH06 HH34 HH39
Claims (1)
方の信号を第１のベクトル調整器を介して主増幅器で増
幅した主増幅信号と他方の信号を第１の遅延手段によっ
て遅延させた信号とを第１の方向性結合器で逆相合成す
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
歪検出ループと、 前記歪検出ループで検出された前記歪成分を第２のベク
トル調整器を介して補助増幅器で増幅した信号と前記主
増幅信号を第２の遅延手段によって遅延させた信号とを
第２の方向性結合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送信信号を出力する歪
除去ループとを備えたフィードフォワード歪補償増幅器
であって、 前記第１の遅延手段は、固定遅延線と該固定遅延線に直
列に接続され切替え制御電圧によって少なくとも２つの
相異なる遅延時間の微調整用遅延線が選択接続される可
変遅延器とで構成され、 前記歪検出ループから検出される前記歪成分のレベルを
監視して前記可変遅延器の微調整用遅延線を切替え制御
する制御手段が設けられ、 前記制御手段は、前記歪成分のレベルが所定の許容値以
上のとき前記切替え制御電圧を変えて前記微調整用遅延
線を切替え接続し歪成分のレベルが小さくなれば更に制
御電圧を変えて前記許容値以下になるまで切替え制御
し、前記微調整用遅延線を切替え接続して歪成分のレベ
ルが大きくなったときは制御電圧を逆の方向に変えて歪
成分のレベルが小さくなれば更に制御電圧を変えて前記
許容値以下になるまで切替え制御するように構成された
ことを特徴とするフィードフォワード歪補償増幅器。An input signal is branched and output by a distributor, and one of the signals is amplified by a main amplifier via a first vector adjuster, and the other signal is delayed by a first delay means. A distortion detection loop for detecting a distortion component generated in the main amplifier by combining the signals obtained by the first and second directional couplers in opposite phases, and a second vector for converting the distortion component detected by the distortion detection loop into a second vector. Distortion generated in the main amplifier by subjecting the signal amplified by the auxiliary amplifier via the adjuster and the signal obtained by delaying the main amplified signal by the second delay means to reverse phase synthesis in the second directional coupler. A feed-forward distortion compensating amplifier having a distortion canceling loop for canceling components and outputting a transmission signal, wherein the first delay means is connected to a fixed delay line and the fixed delay line in series, and is connected to a switching control voltage. By less And a variable delay device to which two delay lines for fine adjustment of different delay times are selectively connected. The level of the distortion component detected from the distortion detection loop is monitored to finely adjust the variable delay device. Control means for switching and controlling the delay line for use, wherein the control means switches and connects the fine adjustment delay line by changing the switching control voltage when the level of the distortion component is equal to or more than a predetermined allowable value. If the level of the distortion component is reduced, the control voltage is further changed to perform switching control until the control voltage becomes equal to or less than the allowable value. The feedforward distortion compensating amplifier is characterized in that the control voltage is further changed when the level of the distortion component becomes smaller by changing the control voltage, and the switching control is performed until the level falls below the allowable value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001071547A JP2002271149A (en) | 2001-03-14 | 2001-03-14 | Feed-forward distortion compensating amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001071547A JP2002271149A (en) | 2001-03-14 | 2001-03-14 | Feed-forward distortion compensating amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002271149A true JP2002271149A (en) | 2002-09-20 |
Family
ID=18929255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001071547A Pending JP2002271149A (en) | 2001-03-14 | 2001-03-14 | Feed-forward distortion compensating amplifier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002271149A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011182288A (en) * | 2010-03-03 | 2011-09-15 | Nec Corp | Power amplifier, and method of controlling the same |
| US8331874B2 (en) | 2005-04-15 | 2012-12-11 | Ivy Biomedical Systems, Inc. | Wireless transmitter |
-
2001
- 2001-03-14 JP JP2001071547A patent/JP2002271149A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8331874B2 (en) | 2005-04-15 | 2012-12-11 | Ivy Biomedical Systems, Inc. | Wireless transmitter |
| JP2011182288A (en) * | 2010-03-03 | 2011-09-15 | Nec Corp | Power amplifier, and method of controlling the same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6326845B1 (en) | Feedforward amplifier | |
| EP1192710B1 (en) | Method and apparatus for linearizing an amplifier | |
| KR19980042391A (en) | Automatic predistortion regulating circuit with stable nonlinear characteristics regardless of input signal frequency | |
| JPH03198407A (en) | Linear amplifier | |
| EP1152523B1 (en) | Feedforward multi-terminal power-synthesizing power amplifier | |
| JPH09503373A (en) | Method and apparatus for feedforward power amplification | |
| US7164738B2 (en) | Signal canceling method and device | |
| WO1995004400A1 (en) | Adaptive feedback system | |
| WO1993019521A1 (en) | Feedforward amplifier | |
| EP1437825B1 (en) | Intermodulation product cancellation in communication systems | |
| JP2002271149A (en) | Feed-forward distortion compensating amplifier | |
| US6940346B2 (en) | Feedforward amplifier, communication apparatus, feedforward amplification method, program and medium | |
| JP4441239B2 (en) | Voltage controlled variable phase shifter | |
| US6392481B1 (en) | Method and apparatus for improved fed forward amplification | |
| KR101131910B1 (en) | Output power unit for a mobile telecommunication equipments | |
| KR100639238B1 (en) | Apparatus and method for multi amplifying in linear power amplifier | |
| JP2001160718A (en) | Power amplifier and linear distortion compensation power amplifier circuit device using the same | |
| KR100349411B1 (en) | Apparatus for adaptive controlling of feed forward linear device | |
| US7088176B2 (en) | Method and arrangement relating to multicarrier power amplifiers | |
| JP7206754B2 (en) | AMPLIFIER, WIRELESS COMMUNICATION DEVICE, AND METHOD OF CONTROLLING AMPLIFIER | |
| JP2002151972A (en) | Distortion compensation power amplifier | |
| JP2004320185A (en) | Predistortion compensation power amplifier | |
| JPH01206709A (en) | Micro-wave and millimeter wave amplifier | |
| JP2002094390A (en) | Active standby nonlinear compensation device and active standby nonlinear compensation method for digital broadcast modulation signal transmission system | |
| JP3324955B2 (en) | Distortion compensation amplifier |