JP2626934B2 - Antenna fault detector - Google Patents
Antenna fault detectorInfo
- Publication number
- JP2626934B2 JP2626934B2 JP3167118A JP16711891A JP2626934B2 JP 2626934 B2 JP2626934 B2 JP 2626934B2 JP 3167118 A JP3167118 A JP 3167118A JP 16711891 A JP16711891 A JP 16711891A JP 2626934 B2 JP2626934 B2 JP 2626934B2
- Authority
- JP
- Japan
- Prior art keywords
- antenna
- output
- detection
- directional coupler
- failure
- 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.)
- Expired - Lifetime
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- Monitoring And Testing Of Transmission In General (AREA)
- Transmitters (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は基地局の無線装置の空中
線障害検出に用いる。本発明は、特にマイクロセル方式
用移動無線基地局装置に接続される空中線の障害検出器
に用いるのに適する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for detecting an antenna fault in a radio equipment of a base station. The present invention is particularly suitable for use in an antenna failure detector connected to a mobile radio base station apparatus for a microcell system.
【０００２】[0002]
【従来の技術】図３は従来の移動通信無線基地局におけ
る空中線の障害検出方法を説明するものである。局舎７
上に設けられた空中線１は給電線２により、局舎内の送
受信装置（ＴＲ）３と接続されている。これとは別に障
害検出用送受信装置（ＴＴＲ）４を設け、給電線５によ
り障害検出用空中線６と接続する構成である。2. Description of the Related Art FIG. 3 illustrates a method of detecting an antenna failure in a conventional mobile communication radio base station. Office building 7
The antenna 1 provided above is connected to a transmitting / receiving device (TR) 3 in a station building by a feeder line 2. In addition to this, a fault detection transmitting / receiving device (TTR) 4 is provided and connected to a fault detecting antenna 6 by a power supply line 5.
【０００３】このような従来の障害検出は、空中線１お
よび障害検出用空中線６を介して障害検出用送受信装置
４と送受信装置３とで無線回線を設定し、障害検出用送
受信装置４と送受信装置３との間で通話等の各種試験を
行うことにより、空中線１を含めた送受信装置３の障害
検出を行うというものであった。In such conventional fault detection, a radio line is set up between the fault detection transmitting / receiving device 4 and the transmitting / receiving device 3 via the antenna 1 and the fault detecting antenna 6, and the fault detecting transmitting / receiving device 4 and the transmitting / receiving device are connected. 3 to perform failure tests of the transmitting and receiving device 3 including the antenna 1 by performing various tests such as a telephone call.
【０００４】このような場合、無線基地局の局舎７内に
収容される送受信装置３および障害検出用送受信装置４
間の筺体輻射は、各装置間でのシールド対策により充分
低レベルに抑えることができるから、あくまでも無線区
間を通じた障害検出が可能であった。すなわち、従来方
法による空中線部分の障害検出とは、空中線を含めた無
線区間全体の障害検出の中に包含されるものであった。In such a case, the transmission / reception device 3 and the failure detection transmission / reception device 4 accommodated in the station 7 of the radio base station are used.
The inter-chassis radiation can be suppressed to a sufficiently low level by the shield measures between the devices, so that the failure detection can be performed through the wireless section. That is, the detection of a fault in the antenna portion according to the conventional method is included in the detection of a fault in the entire wireless section including the antenna.
【０００５】空中線の障害原因としては、給電線のはず
れ、エレメントの破損、アンテナの盗難等が挙げられ
る。このような空中線の障害がマイクロセル方式におけ
る無線基地局に生じた場合について考察してみる。[0005] The causes of failure of the antenna include disconnection of the power supply line, breakage of the element, theft of the antenna, and the like. Let us consider a case where such an antenna failure occurs in a radio base station in the microcell system.
【０００６】[0006]
【発明が解決しようとする課題】マイクロセル方式にお
ける無線基地局においては、基地局装置は大幅に小型化
され、かつ装置の設置自由度はきわめて限定される。す
なわち図４に示すように、例えば公衆電話ボックス８内
に基地局装置を設置する場合を考えると、図３における
局舎内のような設置自由度は確保できず、送受信装置９
および障害検出用送受信装置１０はほとんど隣接して設
置される状況におかれる。このとき、小型化された無線
装置において得られる筺体輻射レベルはおよそ−４０ｄ
Ｂ程度となるため、このような状況下で従来方法による
障害検出を行うと、空中線を介さずに筺体輻射により送
受信装置９と障害検出用送受信装置１０とが筺体輻射レ
ベルにおいて接続されてしまう。すなわち、無線機本体
の障害検出試験は可能であるが、空中線１に障害が発生
したとき、例えば盗難により空中線がなくなった場合、
障害の検出が不能となる事態が発生する欠点があった。SUMMARY OF THE INVENTION In a radio base station in a microcell system, the size of a base station device is greatly reduced, and the degree of freedom in installing the device is extremely limited. That is, as shown in FIG. 4, for example, when a base station device is installed in a public telephone box 8, the degree of freedom of installation as in the station building in FIG.
In addition, the transmission / reception device 10 for failure detection is placed almost adjacently. At this time, the housing radiation level obtained in the miniaturized wireless device is approximately −40 d.
In this situation, if the failure detection is performed by the conventional method under such a situation, the transmission / reception device 9 and the failure detection transmission / reception device 10 are connected at the housing radiation level by the housing radiation without passing through the antenna. That is, although a failure detection test of the wireless device main body is possible, when a failure occurs in the antenna 1, for example, when the antenna disappears due to theft,
There has been a drawback that a situation in which failure detection becomes impossible occurs.
【０００７】また、キャリア周波数が２ＧＨｚ、送信電
力８０ｍＷの場合、筺体輻射レベルをディジタル移動通
信方式におけるキャリアセンスレベル（２０ｄＢμＶ）
以下にするためには、７２ｄＢ以上の伝搬損失を確保す
る必要がある。これは、自由空間伝搬損失で計算しても
結果的に送受信装置９と障害検出用送受信装置１０との
距離が４０ｍ以上必要となるので、同一公衆電話ボック
ス内への設置が困難になることはいうに及ばず、障害検
出機能を含めた基地局設備工事が容易でなくなる欠点が
あった。Further, when the carrier frequency is 2 GHz and the transmission power is 80 mW, the radiation level of the housing is set to the carrier sense level (20 dBμV) in the digital mobile communication system.
In order to achieve the following, it is necessary to secure a propagation loss of 72 dB or more. This means that even if calculation is made based on the free space propagation loss, the distance between the transmitting and receiving device 9 and the transmitting and receiving device 10 for failure detection needs to be 40 m or more, so that installation in the same public telephone box is difficult. Needless to say, there was a disadvantage that the base station facility construction including the failure detection function was not easy.
【０００８】本発明の目的は、上述の欠点を解決してマ
イクロセル方式において使用できる無線基地局装置での
空中線障害検出器を提供することにある。An object of the present invention is to solve the above-mentioned disadvantages and to provide an antenna fault detector in a radio base station apparatus which can be used in a microcell system.
【０００９】[0009]
【課題を解決するための手段】本発明は、無線基地局装
置の空中線の障害検出を行う空中線障害検出器におい
て、無線機の送信電力増幅器の出力端に接続される方向
性結合器と、この方向性結合器の出力端子に接続されそ
の一端が空中線に接続されるサーキュレータと、上記方
向性結合器の補助出力端子に接続される第一の検波回路
手段と、上記サーキュレータの他の端子に接続される第
二の検波回路手段と、この第一および第二の検波回路の
出力を比較する比較回路手段とを備えたことを特徴とす
る。SUMMARY OF THE INVENTION The present invention provides an antenna fault detector for detecting an antenna fault in a radio base station apparatus, comprising: a directional coupler connected to an output terminal of a transmission power amplifier of the radio; A circulator connected to the output terminal of the directional coupler, one end of which is connected to the antenna, first detection circuit means connected to the auxiliary output terminal of the directional coupler, and connected to other terminals of the circulator And a comparison circuit for comparing the outputs of the first and second detection circuits.
【００１０】なお、比較回路手段は、第二の検波回路の
出力から第一の検波回路の出力を減算する減算器を備
え、この減算器の出力を比較器で基準電圧と比較する構
成とすることができる。The comparing circuit means has a subtractor for subtracting the output of the first detection circuit from the output of the second detection circuit, and the output of the subtracter is compared with a reference voltage by the comparator. be able to.
【００１１】[0011]
【作用】送信電力増幅器の出力は方向性結合器によりそ
の一部が分離され、補助出力端子の出力は検波回路によ
ってその電力が検波出力電圧Ｖ2 に変換される。また方
向性結合器の主出力端子は、サーキュレータに接続さ
れ、サーキュレータの一つの端子は空中線に接続され
る。空中線に障害が生じると、サーキュレータの一つの
端子の空中線からの反射波電力が増加する。この反射波
電力は検波回路に導かれて検波出力電圧Ｖ1 に変換され
る。この二つの検波出力電圧Ｖ1 、Ｖ2 を比較して、検
波出力電圧Ｖ1がＶ2 に対して所定比率以上になると、
障害検出出力する。[Action] The output of transmit power amplifier part are separated by the directional coupler, the output of the auxiliary output terminal its power by the detection circuit is converted into the detection output voltage V 2. The main output terminal of the directional coupler is connected to the circulator, and one terminal of the circulator is connected to the antenna. When the antenna fails, the power of the reflected wave from the antenna at one terminal of the circulator increases. The reflected wave power is converted is led to the detection circuit to the detection output voltage V 1. Comparing these two detection output voltages V 1 and V 2 , when the detection output voltage V 1 exceeds a predetermined ratio with respect to V 2 ,
Outputs failure detection output.
【００１２】[0012]
【実施例】以下図面を参照して本発明実施例を説明す
る。Embodiments of the present invention will be described below with reference to the drawings.
【００１３】図１は本発明の一実施例の空中線障害検出
器２１の構成を説明するブロック図である。変調器（Ｍ
ＯＤ）１９の出力は電力増幅器（ＡＭＰ）１４に接続さ
れる。電力増幅器１４の出力は方向性結合器１３に出力
される。方向性結合器１３の主出力端子はサーキュレー
タ１２の一つの端子に接続され、サーキュレータ１２の
他方の端子に空中線１１が接続される。またサーキュレ
ータ１２のもう一つの端子はダイオード等によって構成
される電力を検波出力電圧Ｖ1に変換する検波器（ＤＥ
Ｔ）１６に導かれる。方向性結合器１３の補助出力端子
はやはり電力を検波出力電圧Ｖ2 に変換する検波器１５
に導かれる。検波器１５、１６の検波出力電圧Ｖ1 、Ｖ
2 は、検波出力電圧Ｖ2 から検波出力電圧Ｖ1 を減算す
るアナログ減算器（ＳＵＢ）１７に導かれる。アナログ
減算器１７の出力は基準電圧Ｖ0と比較する比較器（Ｃ
ＯＭＰ）１８に導かれる。比較器１８は、アナログ減算
器１７の出力が基準電圧Ｖr を下回ったとき障害検出を
意味する比較信号「１」をその出力端子に出力するよう
に構成される。FIG. 1 is a block diagram illustrating the configuration of an antenna failure detector 21 according to one embodiment of the present invention. Modulator (M
The output of the OD 19 is connected to the power amplifier (AMP) 14. The output of the power amplifier 14 is output to the directional coupler 13. The main output terminal of the directional coupler 13 is connected to one terminal of the circulator 12, and the antenna 11 is connected to the other terminal of the circulator 12. The detector Another terminal of the circulator 12 for converting power constituted by a diode or the like to the detection output voltage V 1 (DE
T) 16. Auxiliary output terminal of the directional coupler 13 also converts the power to the detection output voltage V 2 detector 15
It is led to. The detection output voltages V 1 and V of the detectors 15 and 16
2 is directed to an analog subtractor (SUB) 17 for subtracting the detection output voltages V 1 from the detection output voltage V 2. Comparator output of the analog subtractor 17 is compared with the reference voltage V 0 (C
OMP) 18. The comparator 18 is configured to output a comparison signal "1" indicating a fault detection when the output of the analog subtractor 17 is lower than the reference voltage V r at its output terminal.
【００１４】ここで、本実施例は、サーキュレータ１２
を用いて空中線１１に障害発生したとき空中線１１の電
圧定在波比（ＶＳＷＲ）が悪化することにより、サーキ
ュレータ１２のもう一方の端子に現れる反射電力を検出
し比較器１８で比較することにより障害発生を検出出力
する構成であるところに特徴がある。In this embodiment, the circulator 12
When a fault occurs in the antenna 11 by using the above, the voltage standing wave ratio (VSWR) of the antenna 11 deteriorates, and the reflected power appearing at the other terminal of the circulator 12 is detected and compared by the comparator 18. It is characterized in that the occurrence is detected and output.
【００１５】次に本実施例の動作を説明する。Next, the operation of this embodiment will be described.
【００１６】障害が発生せずに空中線１１が通常の状態
で使用されているとき、送信機の電力増幅器１４からの
出力電力ＰO は方向性結合器１３およびサーキュレータ
１２を通過して空中線１１に入力される。空中線の電圧
定在波比（ＶＳＷＲ）は通常１．５以下であるため、出
力電力ＰO に対して１４ｄＢ以下（すなわちＰ1 ＝ＰO
−１４ｄＢ）のレベルの反射電力Ｐ1 が空中線１１の入
力端より反射し、サーキュレータ１２を通って検波器１
６に入力される。検波器１６は、空中線１１からの反射
波電力が検波されて検波出力電圧Ｖ1 に変換される。一
方、方向性結合器１３の補助出力端子２０から出力され
る電力は検波器１５に入力され、電力増幅器１４からの
出力電力ＰO に対応する検波出力電圧Ｖ2 が生成され
る。[0016] When the antenna 11 without failure occurs is used in normal conditions, the output power P O of the power amplifier 14 of the transmitter to the antenna 11 through the directional coupler 13 and the circulator 12 Is entered. Since the voltage standing wave ratio (VSWR) of the antenna is usually 1.5 or less, the output power P O is 14 dB or less (that is, P 1 = P O).
The reflected power P 1 at the level of −14 dB) is reflected from the input end of the antenna 11 and passes through the circulator 12 to detect the detector 1
6 is input. The detector 16 detects the reflected wave power from the antenna 11 and converts the detected power to a detection output voltage V 1 . Meanwhile, power output from the auxiliary output terminal 20 of the directional coupler 13 is input to the detector 15, the detection output voltage V 2 corresponding to the output power P O of the power amplifier 14 is generated.
【００１７】これら二つの検波出力電圧Ｖ1 、Ｖ2 はア
ナログ減算器１７に入力され、これら電圧の差電圧Ｖ3
＝Ｖ2 −Ｖ1 が出力される。比較器１８ではあらかじめ
設定された基準電圧Ｖr と比較し、図２の符号２２の正
常時特性領域に示されるとおり差電圧Ｖ3 （２４）が基
準電圧Ｖr を上回った場合には比較器１８の出力信号２
５として比較信号「０」を出力する。The two detection output voltages V 1 and V 2 are input to an analog subtractor 17 and a difference voltage V 3 between these voltages is output.
= V 2 -V 1 is output. The comparator 18 compares a preset reference voltage V r, the comparator when as differential voltage V 3 shown in normal time characteristic area of the reference numeral 22 in FIG. 2 (24) exceeds the reference voltage V r 18 output signal 2
As 5, the comparison signal “0” is output.
【００１８】ところで、盗難、いたずら等によって空中
線の欠落や破損、あるいは空中線になんらかの物体が近
接したときのように障害が発生した場合には、空中線１
１のＶＳＷＲ特性が著しく劣化して空中線が正常に動作
しなくなる。このとき、空中線１１からの反射波電力が
著しく増加して検波器１６の検波出力電圧Ｖ1 が増加す
ることになるから、アナログ減算器１７の差電圧出力Ｖ
3 ＝Ｖ2 −Ｖ1 が小さくなる。この結果、図２の符号２
３の障害時特性の場合に示されるとおり、比較器１８に
おいて差電圧Ｖ3 （２４）が基準電圧Ｖr を著しく下回
る。このとき比較信号「１」が出力されて空中線に障害
の発生したことを検出することができる。When the antenna is missing or damaged due to theft, mischief, or the like, or when an obstacle occurs, such as when an object approaches the antenna, the antenna 1
The VSWR characteristic of No. 1 significantly deteriorates, and the antenna does not operate normally. At this time, the power of the reflected wave from the antenna 11 is significantly increased and the detection output voltage V 1 of the detector 16 is increased.
3 = V 2 -V 1 is reduced. As a result, reference numeral 2 in FIG.
As shown in the case of 3 disaster characteristic, the differential voltage V 3 in the comparator 18 (24) is significantly less than the reference voltage V r. At this time, the comparison signal "1" is output, and it is possible to detect that a failure has occurred in the antenna.
【００１９】本発明の構成によれば、変調器１９がＱＰ
ＳＫ等の包絡線変動を伴う構成であったとしても、方向
性結合器１３の補助出力端子２０の電力と検波器１６に
入力される反射波電力とは同時に同じレベルだけ変動す
るため、アナログ減算器１７の出力は送信電力変動に無
関係に一定となる利点を有する。同様に、マルチキャリ
アＴＤＭＡ方式の場合においても、使用チャネル数の変
動によって送信電力が変動するが、本構成の場合、アナ
ログ減算器１７の出力は送信電力変動に無関係に常に一
定となるので、空中線の障害検出器として安定した動作
を行うことができる。According to the structure of the present invention, the modulator 19
Even if the configuration involves an envelope variation such as SK, the power of the auxiliary output terminal 20 of the directional coupler 13 and the reflected wave power input to the detector 16 fluctuate by the same level at the same time. This has the advantage that the output of the unit 17 is constant irrespective of the transmission power fluctuation. Similarly, also in the case of the multi-carrier TDMA system, the transmission power fluctuates due to the fluctuation of the number of channels used. However, in the case of this configuration, the output of the analog subtractor 17 is always constant regardless of the fluctuation of the transmission power. Stable operation can be performed as a fault detector.
【００２０】なお、上記実施例では、比較手段としてア
ナログ減算器１７によって二つの検波出力電圧を減算し
てこれを基準電圧と比較する構成としたが、比較手段と
しては、二つの検波出力電圧の比をとってもよい。すな
わち二つの検波出力電圧を一定の基準のもとに比較でき
る構成とすればよい。また、二つの空中線を用いた送信
ダイバーシチを行う無線通信装置において本発明を適用
する場合には、周期的に送出する基地局の標識信号等を
交互に各空中線から送出することにより、この二つの空
中線の障害検出を行うこともできる。In the above-described embodiment, the two detection output voltages are subtracted by the analog subtractor 17 and compared with the reference voltage as the comparison means. However, the comparison means uses the two detection output voltages of the two detection output voltages. A ratio may be taken. That is, the configuration may be such that the two detection output voltages can be compared based on a certain reference. In addition, when the present invention is applied to a wireless communication device that performs transmission diversity using two antennas, a beacon signal of a base station that is periodically transmitted is alternately transmitted from each antenna, whereby the two antennas are transmitted. Antenna fault detection can also be performed.
【００２１】[0021]
【発明の効果】以上説明したように、本発明はマルチキ
ャリアＴＤＭＡ方式やＱＰＳＫ変調等を用いる通信方式
に対しても安定した空中線障害検出器として動作するた
め、マイクロセル方式を採用する移動通信用基地局無線
装置に接続する空中線障害検出器として有効である。As described above, the present invention operates as an antenna failure detector which is stable even in a communication system using a multi-carrier TDMA system or QPSK modulation. It is effective as an antenna failure detector connected to a base station radio apparatus.
【図１】本発明一実施例の構成を示すブロック図。FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
【図２】実施例のアナログ減算器の差電圧と基準電圧と
の関係を示す図。FIG. 2 is a diagram illustrating a relationship between a difference voltage and a reference voltage of the analog subtractor according to the embodiment.
【図３】従来の移動通信無線基地局における空中線障害
検出方法を説明する図。FIG. 3 is a diagram illustrating an antenna failure detection method in a conventional mobile communication radio base station.
【図４】公衆電話ボックス等の内部に基地局装置を設置
した場合の従来の空中線障害検出方法を説明する図。FIG. 4 is a diagram illustrating a conventional antenna failure detection method when a base station device is installed inside a public telephone box or the like.
１、１１ 空中線 ２、５ 給電線 ３、９ 送受信装置 ４、１０ 障害検出用送受信装置 ６ 障害検出用空中線 ７ 局舎 ８ 公衆電話ボックス １２ サーキュレータ １３ 方向性結合器 １４ 電力増幅器 １５、１６ 検波器 １７ アナログ減算器 １８ 比較器 １９ 変調器 ２０ 方向性結合器の補助出力端子 ２１ 空中線障害検出器 ２２ 正常時特性 ２３ 障害時特性 ２４ アナログ減算器１７の差電圧 ２５ 比較器１８の出力信号 DESCRIPTION OF SYMBOLS 1, 11 Antenna 2, 5 Feeding line 3, 9 Transceiver 4, 10 Failure detection transceiver 6 Antenna for failure detection 7 Office building 8 Public telephone box 12 Circulator 13 Directional coupler 14 Power amplifier 15, 16 Detector 17 Analog subtractor 18 Comparator 19 Modulator 20 Auxiliary output terminal of directional coupler 21 Antenna failure detector 22 Normal characteristic 23 Failure characteristic 24 Difference voltage of analog subtracter 17 25 Output signal of comparator 18
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭58−115942（ＪＰ，Ａ) 特開 昭58−178645（ＪＰ，Ａ) 特開 昭60−264131（ＪＰ，Ａ) 特開 昭64−7718（ＪＰ，Ａ) 実開 昭59−52737（ＪＰ，Ｕ) ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-115942 (JP, A) JP-A-58-178645 (JP, A) JP-A-60-264131 (JP, A) JP-A 64-64 7718 (JP, A) Actually open sho 59-52737 (JP, U)
Claims (2)
う空中線障害検出器において、 無線機の送信電力増幅器の出力端に接続される方向性結
合器と、 この方向性結合器の出力端子に接続されその一端が空中
線に接続されるサーキュレータと、 上記方向性結合器の補助出力端子に接続される第一の検
波回路手段と、 上記サーキュレータの他の端子に接続される第二の検波
回路手段と、 この第一および第二の検波回路の出力を比較する比較回
路手段と を備えたことを特徴とする空中線障害検出器。An antenna fault detector for detecting an antenna fault in a radio base station apparatus, comprising: a directional coupler connected to an output terminal of a transmission power amplifier of a radio, and an output terminal of the directional coupler. A circulator, one end of which is connected to an antenna, a first detection circuit connected to an auxiliary output terminal of the directional coupler, and a second detection circuit connected to another terminal of the circulator. And an comparing circuit means for comparing the outputs of the first and second detection circuits.
から第一の検波回路の出力を減算する減算器を備え、こ
の減算器の出力を比較器で基準電圧と比較する請求項１
記載の空中線障害検出器。2. The comparison circuit means includes a subtractor for subtracting the output of the first detection circuit from the output of the second detection circuit, and the output of the subtractor is compared with a reference voltage by the comparator.
An antenna fault detector as described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3167118A JP2626934B2 (en) | 1991-07-08 | 1991-07-08 | Antenna fault detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3167118A JP2626934B2 (en) | 1991-07-08 | 1991-07-08 | Antenna fault detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0514291A JPH0514291A (en) | 1993-01-22 |
| JP2626934B2 true JP2626934B2 (en) | 1997-07-02 |
Family
ID=15843775
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3167118A Expired - Lifetime JP2626934B2 (en) | 1991-07-08 | 1991-07-08 | Antenna fault detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2626934B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100473934B1 (en) * | 2000-08-02 | 2005-03-07 | 엘지전자 주식회사 | transmitter system having a function for detecting reflection wave |
| WO2002096858A1 (en) * | 2001-05-31 | 2002-12-05 | Bristol-Myers Squibb Company | Cinnamide derivatives as kcnq potassium channel modulators |
| US7353020B2 (en) | 2003-11-17 | 2008-04-01 | Hitachi Communication Technologies, Ltd. | Radio access point testing apparatus and method of testing radio access point |
| JP4299641B2 (en) | 2003-11-17 | 2009-07-22 | 株式会社日立コミュニケーションテクノロジー | Radio base station test method and test apparatus |
| US7907908B2 (en) | 2004-08-04 | 2011-03-15 | Hitachi, Ltd. | Radio access point testing apparatus and method of testing radio access point |
| JP4855267B2 (en) * | 2004-11-30 | 2012-01-18 | 富士通株式会社 | Signal extraction circuit and distortion compensation amplifier having the same |
| JP7091563B2 (en) * | 2018-12-31 | 2022-06-27 | クオンタム ヴァリー アイデアズ ラボラトリーズ | Antenna system for inspection |
-
1991
- 1991-07-08 JP JP3167118A patent/JP2626934B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0514291A (en) | 1993-01-22 |
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