JPH07105754B2 - Diversity receiver - Google Patents
Diversity receiverInfo
- Publication number
- JPH07105754B2 JPH07105754B2 JP61036579A JP3657986A JPH07105754B2 JP H07105754 B2 JPH07105754 B2 JP H07105754B2 JP 61036579 A JP61036579 A JP 61036579A JP 3657986 A JP3657986 A JP 3657986A JP H07105754 B2 JPH07105754 B2 JP H07105754B2
- Authority
- JP
- Japan
- Prior art keywords
- level
- receiving system
- sensitivity
- receiving
- reception
- 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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Description
【発明の詳細な説明】 「産業上の利用分野」 この発明は例えば移動通信において高速で深いフェージ
ングによる通信品質の劣化を克服するため複数の受信系
から受信レベルの常に大きい受信系の出力信号を選択す
るダイバーシチ受信機に関するものである。DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention, for example, in mobile communication, in order to overcome deterioration of communication quality due to high speed and deep fading, output signals from a plurality of receiving systems, which are always high in receiving level, are output. It relates to a diversity receiver of choice.
「従来の技術」 陸上移動通信では、建造物，地物等の反射，屈折，散乱
により定在波性の電磁界分布が形成され、移動局の走行
に伴い、マルチパスフェージングが生じる。この高速で
深いフェージングによる通信品質の劣化を克服するため
に複数の受信系列を設け、受信レベルの最も大きい受信
系出力を選択するダイバーシチ受信機がある。“Prior Art” In land mobile communication, a standing wave electromagnetic field distribution is formed by reflection, refraction, and scattering of structures, features, etc., and multipath fading occurs as the mobile station travels. In order to overcome the deterioration of communication quality due to the high speed and deep fading, there is a diversity receiver in which a plurality of reception sequences are provided and a reception system output with the highest reception level is selected.
第１図は２つの受信系を有するダイバーシチ受信機を示
し、受信アンテナ1a及び1bで受信した信号Sa及びSbはそ
れぞれ高周波、中間周波（RF,IF）部2a及び2bに供給さ
れる。RF,IF部2a及び2bの各々の中間周波出力信号IFa,I
Fbはレベル検出器3a及び3bにそれぞれ供給されるととも
に検波器4a及び4bに供給されて復調信号ma及びmbが検波
器出力として得られる。レベル検出器3a及び3bよりのレ
ベル検出出力信号ra及びrbは、比較器５で大小が比較判
定される。ra≧rbならば復調信号maを選択し、ra＜rbな
らば復調信号mbを選択するように比較器５の出力により
切替スイッチ６が制御され、出力端子７には切替スイッ
チ６の切替え後の復調出力信号mcが得られる。FIG. 1 shows a diversity receiver having two receiving systems. The signals Sa and Sb received by the receiving antennas 1a and 1b are supplied to high frequency and intermediate frequency (RF, IF) units 2a and 2b, respectively. Intermediate frequency output signal IFa, I of each of RF and IF sections 2a and 2b
Fb is supplied to the level detectors 3a and 3b, respectively, and is also supplied to the detectors 4a and 4b, and the demodulated signals m a and m b are obtained as detector outputs. The level detection output signals r a and r b from the level detectors 3a and 3b are compared and judged by the comparator 5. When r a ≧ r b , the demodulated signal m a is selected, and when r a <r b , the demodulated signal m b is selected. The selector switch 6 is controlled by the output of the comparator 5, and the output terminal 7 is switched. A demodulated output signal m c after switching of the switch 6 is obtained.
マルチパスフェージング下では受信信号振幅は数＋dBに
わたり変動するため、対数圧縮してレベル検出を行う。
受信信号振幅（受信電界レベル）をｘとすると、レベル
検出器の出力ｙは次式のように表わされる。Since the received signal amplitude fluctuates over several + dB under multipath fading, logarithmic compression is performed to detect the level.
When the received signal amplitude (received electric field level) is x, the output y of the level detector is expressed by the following equation.
ｙ＝aln（bx）（a,b＞０） （１） 従来、この種のダイバーシチ受信機のレベル検出特性は
第２図に示すように、受信アンテナ1a,1bよりの各受信
系1,2のレベル検出出力をy1,y2とすると、 となるようにレベル検出特性を一致させていた。受信系
1,2の受信信号振幅をx1,x2、平均雑音電力をN1,N2とす
ると、式（２）よりダイバーシチ後の瞬時搬送波対雑音
電力比（瞬時CNR）γＳは となる。ここで、受信系２の感度が受信系１の感度より
も悪い（N2＞N1）とする。式（３）において、 の関係のとき、x1＝C, とおくと、受信系１の瞬時CNRγ１は 受信系２の瞬時CNRγ２は となり、γ２＜γ１となる。すなわち、受信レベルの高
い方の受信系２に切替えているにもかかわらず、受信系
２の瞬時CNRγ２が受信系１の瞬時CNRγ１よりも小さい
場合が生じる。y = aln (bx) (a, b> 0) (1) Conventionally, the level detection characteristic of this type of diversity receiver is as shown in FIG. 2 as shown in FIG. Let y 1 and y 2 be the level detection outputs of The level detection characteristics are matched so that Receiving system
The received signal amplitude of 1,2 x 1, x 2, when the average noise power and N 1, N 2, the instantaneous carrier to noise power ratio after diversity from the equation (2) (instantaneous CNR) gamma S is Becomes Here, it is assumed that the sensitivity of the receiving system 2 is lower than the sensitivity of the receiving system 1 (N 2 > N 1 ). In equation (3), X 1 = C, Then, the instantaneous CNR γ 1 of the receiving system 1 is The instantaneous CNRγ 2 of the receiving system 2 is And γ 2 <γ 1 . That is, there is a case where the instantaneous CNRγ 2 of the receiving system 2 is smaller than the instantaneous CNRγ 1 of the receiving system 1 despite switching to the receiving system 2 having the higher receiving level.
このことは、受信レベルによって切替えても選択した受
信系の瞬時CNRが他方の受信系の瞬時CNRよりも小さいこ
とがあり、この場合は切替後の復調信号のベースバンド
信号対雑音電力比（SNR）が劣化する。This means that the selected receiving system's instantaneous CNR may be smaller than the other receiving system's instantaneous CNR even if switching is performed depending on the receiving level.In this case, the baseband signal-to-noise power ratio (SNR) of the demodulated signal after switching is changed. ) Is deteriorated.
例えば、第３図は受信系１及び受信系２の受信感度をパ
ラメータとしたときの復調出力信号のベースバンドSNR
特性（実測値）である。横軸は受信入力レベル、縦軸は
ベースバンドSNRである。第３図中の曲線11は受信系１
及び受信系２の感度がともに−3dBμ、第３図曲線12は
受信系１の感度が−3dBμ、受信系２の感度が−1dBμの
ときであり、平均SNR12dBを得る所要の受信レベルは第
３図曲線11では2dBμ、第３図曲線12では3dBμである。
従って感度が2dB劣化すると所要の受信入力レベルは1dB
増加する。For example, FIG. 3 shows the baseband SNR of the demodulated output signal when the receiving sensitivity of the receiving system 1 and the receiving system 2 is used as a parameter.
It is a characteristic (actual measurement value). The horizontal axis is the reception input level, and the vertical axis is the baseband SNR. Curve 11 in FIG. 3 is the receiving system 1
And the sensitivity of the receiving system 2 is both -3 dBμ, and the curve 12 in FIG. 3 is when the sensitivity of the receiving system 1 is -3 dBμ and the sensitivity of the receiving system 2 is -1 dBμ, and the required receiving level for obtaining the average SNR of 12 dB is the third. The curve 11 is 2 dBμ, and the curve 12 of FIG. 3 is 3 dBμ.
Therefore, if the sensitivity deteriorates by 2 dB, the required reception input level is 1 dB.
To increase.
以上のように感度差がある受信系よりなるダイバーシチ
受信機では受信レベルのみで受信系の切替を行うと選択
された受信系の瞬時CNRが他方受信系の瞬時CNRよりも小
さい場合が生じるためダイバーシチ特性の劣化が大きい
という欠点があった。As described above, in a diversity receiver consisting of receiving systems with different sensitivities, if the receiving system is switched only by the receiving level, the instantaneous CNR of the selected receiving system may be smaller than the instantaneous CNR of the other receiving system. There was a drawback that the deterioration of the characteristics was large.
この発明の目的は受信系の感度差によるダイバーシチ特
性の劣化を解決したダイバーシチ受信機を提供すること
にある。An object of the present invention is to provide a diversity receiver which solves the deterioration of diversity characteristics due to the sensitivity difference of the receiving system.
この発明はダイバーシチ受信機の受信系のレベル検出特
性が、感度が最も悪い受信系のレベル検出特性に対し、
受信レベル軸に沿って低い方に最も悪い受信系の感度と
の感度差だけシフトされている。この構成により瞬時CN
Rの大小が判定されることになり、常に瞬時CNRの大きい
方の受信系が選択されることになる。従来のダイバーシ
チ受信機の各受信系のレベル検出特性は常に互いに一致
されており、受信レベルの大小により常に受信レベルの
高い受信系の選択を行っていたが、この発明では受信系
のレベル検出特性がその受信系の感度に応じて差が設け
られて、瞬時CNRの常に大きい受信系が選択される点が
従来のダイバーシチ受信機と異なる。This invention has a level detection characteristic of the reception system of the diversity receiver, which is the most sensitive to the level detection characteristic of the reception system.
Along the reception level axis, it is shifted to the lower side by the sensitivity difference from the sensitivity of the worst reception system. Instant CN with this configuration
The magnitude of R will be determined, and the receiving system with the larger instantaneous CNR will always be selected. The level detection characteristics of each receiving system of the conventional diversity receiver are always matched with each other, and the receiving system having the high receiving level is always selected according to the magnitude of the receiving level. However, a difference is provided depending on the sensitivity of the receiving system, and the point that a receiving system with a constantly large instantaneous CNR is selected is different from the conventional diversity receiver.
「実施例」 この発明の実施例を説明する。受信系１の感度が受信系
２の感度よりβdBだけ高い場合は、この発明においては
第４図に示すように受信信号振幅がそれぞれ、 ｘ＝x1,x＝x2のとき受信系１及び受信系２のレベル検出
出力y1,y2が等しくなるように両レベル検出特性に差が
付けられている。"Example" An example of the present invention will be described. When the sensitivity of the receiving system 1 is higher than the sensitivity of the receiving system 2 by β dB, in the present invention, when the received signal amplitudes are x = x 1 and x = x 2 , respectively, as shown in FIG. Both level detection characteristics are different so that the level detection outputs y 1 and y 2 of the reception system 2 are equal.
y1＝aln（b1x1）…受信系１ （ａ＞0,b1＞0,b2＞0,b1≠b2） y2＝aln（b2x2）…受信系２ （４） そのレベル偏差lnx2−lnx1をβ（dB）とすると、 で表わされる。y 1 = aln (b 1 x 1 ) ... Receiving system 1 (a> 0, b 1 > 0, b 2 > 0, b 1 ≠ b 2 ) y 2 = aln (b 2 x 2 ) ... Receiving system 2 ( 4) If the level deviation lnx 2 −lnx 1 is β (dB), It is represented by.
この発明では受信系1,2のレベル検出特性がこのように
選定されているため、瞬時CNRの大小を判定して、瞬時C
NRの大きい受信系を選択することになることを以下に説
明する。即ち瞬時CNRの大きい受信系を選択することは
ダイバーシチ後、つまり選択された出力の瞬時CNRγＳ
は となる。式（６）は次式のように書き直すことができ
る。In the present invention, the level detection characteristics of the receiving systems 1 and 2 are selected in this way, so the magnitude of the instantaneous CNR is judged to determine the instantaneous CNR.
It will be described below that a receiving system with a large NR will be selected. That is, selecting a receiving system with a large instantaneous CNR is after diversity, that is, the instantaneous CNR γ S of the selected output.
Is Becomes Expression (6) can be rewritten as the following expression.
実際のダイバーシチ受信機では式（４）のy1,y2の値の
大小により受信系１及び受信系２を選択するから、 が成立する。従って、式（８）が式（７）と一致するた
めには とすればよい。式（５）及び式（９）よりレベル偏差β
は β＝10logN2−10logN1 （10） となる。式（10）は受信系１と受信系２の感度差だけレ
ベル検出特性に差を設けることを示している。すなわ
ち、受信感度の良い方の受信系のレベル検出特性を、受
信感度の悪い方の受信系のレベル検出特性に対し受信入
力レベル軸に沿って低い方に感度差βだけシフトすれば
よい。つまり第４図に示したようにレベル検出特性を選
定することにより、瞬時CNRの大きい方の受信系出力を
選択することになる。 In an actual diversity receiver, since the receiving system 1 and the receiving system 2 are selected according to the magnitude of the values of y 1 and y 2 in the equation (4), Is established. Therefore, in order for expression (8) to match expression (7), And it is sufficient. From the equations (5) and (9), the level deviation β
Is β = 10logN 2 −10logN 1 (10). Expression (10) indicates that the level detection characteristics are different by the sensitivity difference between the receiving system 1 and the receiving system 2. That is, the level detection characteristic of the receiving system having the higher receiving sensitivity may be shifted to the lower side along the receiving input level axis by the sensitivity difference β with respect to the level detection characteristic of the receiving system having the lower receiving sensitivity. That is, by selecting the level detection characteristic as shown in FIG. 4, the receiving system output with the larger instantaneous CNR is selected.
第５図は受信入力レベルを一定にしたときのレベル偏差
βに対するベースバンドSNR（実測値）である。第５図
中の曲線13は受信系１、受信系２の受信感度がともに−
3dBμのときであり、β＝0dBでベースバンドSNRは最大
となり、曲線14は受信系１の受信感度が−3dBμ、受信
系２の受信感度が−5dBμのときであり、β＝−2dBでベ
ースバンドSNRは最大となる。また、曲線15は受信系１
の受信感度が−3dBμ、受信系２の受信感度が−1dBμで
あり、β＝2dBでベースバンドSNRは最大となる。従来は
β＝0dBに設定しており、受信系に感度差があるとき
は、最適な条件ではないことがわかる。FIG. 5 shows the baseband SNR (measured value) with respect to the level deviation β when the reception input level is fixed. Curve 13 in FIG. 5 shows that the receiving sensitivity of receiving system 1 and receiving system 2 is −
The baseband SNR is maximum at β = 0 dB at 3 dBμ, and the curve 14 is when the receiving sensitivity of receiving system 1 is −3 dBμ and the receiving sensitivity of receiving system 2 is −5 dBμ, and β = −2 dB is the base. Band SNR is maximum. Curve 15 is the receiving system 1
Has a reception sensitivity of −3 dBμ, the reception system 2 has a reception sensitivity of −1 dBμ, and β = 2 dB maximizes the baseband SNR. Conventionally, β is set to 0 dB, and it can be seen that it is not the optimum condition when there is a sensitivity difference in the receiving system.
第６図は受信系１及び受信系２の受信感度をパラメータ
としたときの受信入力レベルに対するベースバンドSNR
（実測値）である。第６図において、従来のレベル偏差
無し（β＝0dB）のときは曲線15,16,17に示すように受
信系1,2に感度差がある場合はベースバンドSNRが感度差
がない場合（ｘ印）よりも劣化があるが、式（10）のよ
うに最適条件にレベル偏差βを設定すれば、受信系1,2
に感度差があっても、第６図中のｘ印のように受信系１
の感度−3dBμ、受信系２の感度−3dBμ（感度差なし）
のダイバーシチ受信機の特性と一致している。つまり、
レベル偏差βを設けて瞬時CNRの常に高い受信系を選択
するようにすれば、受信系１と受信系２との平均感度を
各々有するダイバーシチ受信機と同じ特性が得られる。
第６図、受信感度−6dBμの単一受信機のベースバンドS
NR（第６図曲線18ダイバーシチ無し）を基準にすると平
均SNR12dBを得る所要の受信入力レベルはレベル偏差無
し（β＝0dB）のとき4.5dB低減され、レベル偏差有りβ
＝−6dBのとき、さらに4dB低減される。このように、レ
ベル偏差を設ける方式は受信系１と受信系２との感度差
が大きいほど有効であるといえる。Figure 6 shows the baseband SNR for the received input level when the receiving sensitivity of receiving system 1 and receiving system 2 is used as a parameter.
(Actual measurement value). In FIG. 6, when there is no conventional level deviation (β = 0 dB), there is a difference in sensitivity between the receiving systems 1 and 2 as shown by curves 15, 16 and 17, and there is no difference in sensitivity in the baseband SNR ( Although there is deterioration compared to (x mark), if the level deviation β is set to the optimum condition as shown in equation (10), the reception system 1, 2
Even if there is a difference in sensitivity, the receiving system 1 as shown by the x mark in FIG.
Sensitivity-3dBμ, reception system 2 sensitivity-3dBμ (no sensitivity difference)
This is consistent with the characteristics of the diversity receiver of. That is,
By providing the level deviation β so as to select the receiving system having the always high instantaneous CNR, the same characteristics as the diversity receiver having the average sensitivities of the receiving system 1 and the receiving system 2 can be obtained.
Fig.6 Baseband S of single receiver with receiver sensitivity of -6dBμ
Obtaining an average SNR of 12 dB based on NR (Fig. 6 curve 18 without diversity) The required reception input level is reduced by 4.5 dB when there is no level deviation (β = 0 dB), and there is level deviation β
When -6 dB, it is further reduced by 4 dB. Thus, it can be said that the method of providing the level deviation is more effective as the sensitivity difference between the receiving system 1 and the receiving system 2 is larger.
「発明の効果」 以上説明したように、この発明によれば受信系の感度が
互いに異なるダイバーシチ受信機において各受信系のレ
ベル検出特性に差を設け同一の瞬時CNRの場合にほぼ同
一検出レベルとなるようにされているため、各受信系の
検出レベルの大小を判定して常に瞬時CNRの大きい受信
系を選択することになり、受信感度の値にかかわらず常
に各受信系の感度を平均した感度を有するダイバーシチ
受信機と同じ特性が得られる。[Advantages of the Invention] As described above, according to the present invention, in the diversity receivers having different receiving system sensitivities, the level detecting characteristics of the receiving systems are made different from each other, and substantially the same detecting level is obtained in the case of the same instantaneous CNR. Therefore, the detection level of each receiving system is judged and the receiving system with a large instantaneous CNR is always selected, and the sensitivity of each receiving system is always averaged regardless of the value of the receiving sensitivity. It provides the same characteristics as a sensitive diversity receiver.
検出レベル偏差を設ける方法としては、最初、受信系１
及び受信系２に同じレベルを入力し、次に、感度の良い
方の受信系の受信入力レベルを感度差だけ小さくしてレ
ベル検出特性を一致させたのち受信レベルを最初のレベ
ルに戻すだけでよく非常に簡単である。As a method of providing the detection level deviation, first, the receiving system 1
And the same level is input to the receiving system 2, and then the receiving input level of the receiving system with higher sensitivity is reduced by the sensitivity difference to match the level detection characteristics, and then the receiving level is returned to the initial level. Well very simple.
この発明によれば受信感度の異なる受信系が３つ以上の
場合についても、各受信系のレベル検出特性を、感度が
最も悪い受信系のレベル検出特性に対し、その受信系の
感度と最も悪い感度との差だけ受信レベル軸に沿って低
い方へずらせばよく、これにより各受信系の感度を平均
した感度を有するダイバーシチ受信機と同じ特性が得ら
れる。従って、平均感度を良くするようにダイバーシチ
受信機の設計を行えばよい。According to the present invention, even when there are three or more receiving systems having different receiving sensitivities, the level detecting characteristics of each receiving system are the worst with respect to the receiving system having the lowest sensitivity. It is only necessary to shift it to the lower side along the reception level axis by the difference from the sensitivity, and the same characteristic as the diversity receiver having the sensitivity obtained by averaging the sensitivities of the respective reception systems can be obtained. Therefore, the diversity receiver may be designed to improve the average sensitivity.
さらに、この発明によれば一方には損失の小さい高周波
数フイルタを用い、他方には受信系の入力に挿入損失の
大きいSAWフィルタ（弾性表面波フィルタ）を適用し
て、この他方の受信機の小型化を図り、全体としても小
型化することができるのが大きな利点である。Further, according to the present invention, a high-frequency filter with small loss is used for one side, and a SAW filter (surface acoustic wave filter) with a large insertion loss is applied to the input of the receiving system for the other side of the other receiver. It is a great advantage that it can be miniaturized and can be miniaturized as a whole.
第１図はダイバーシチ受信機の構成例を示すブロック
図、第２図は従来のダイバーシチ受信機のレベル検出特
性を示す図、第３図は受信入力レベルに対するベースバ
ンドSNR特性図、第４図はこの発明のダイバーシチ受信
機のレベル検出特性の例を示す図、第５図はレベル偏差
に対するベースバンドSNR特性図、第６図は受信入力レ
ベルに対するベースバンドSNR特性図である。FIG. 1 is a block diagram showing a configuration example of a diversity receiver, FIG. 2 is a diagram showing a level detection characteristic of a conventional diversity receiver, FIG. 3 is a baseband SNR characteristic diagram with respect to a reception input level, and FIG. FIG. 5 is a diagram showing an example of level detection characteristics of the diversity receiver of the present invention, FIG. 5 is a baseband SNR characteristic diagram with respect to a level deviation, and FIG. 6 is a baseband SNR characteristic diagram with respect to a reception input level.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭51−80109（ＪＰ，Ａ) 特開 昭53−120211（ＪＰ，Ａ) 昭和61年度電子通信学会総合全国大会講 演論文集 分冊10、昭和61年３月５日、電 子通信学会「2366 ブランチ間偏差のある ダイバーシチ受信特性の検討」Ｐ．10−99 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-51-80109 (JP, A) JP-A-53-120211 (JP, A) Proceedings of the 61st Annual Conference of IEICE General Conference, Volume 10, March 5, 1986, IEICE "2366 Diversity reception characteristics with branch deviation", p. 10−99
Claims (1)
テナの受信信号をそれぞれ検波器で検波する複数の受信
系を備え、 上記各受信信号のレベルをレベル検出器でそれぞれ検出
し、これら検出レベル中の最大のものと対応する受信系
の検波出力を切替えスイッチで選択して取出すダイバー
シチ受信機において、 上記各受信系のレベル検出器のレベル検出特性は、上記
複数の受信系中の最も悪い感度に対するその受信系の感
度差だけ、上記最も悪い感度の受信系のレベル検出器の
レベル検出特性に対し、受信入力レベル軸に沿って低い
方へずれていることを特徴とするダイバーシチ受信機。1. A plurality of receiving systems for respectively detecting received signals of a plurality of receiving antennas spatially separated from each other by a detector, the level of each received signal being detected by a level detector, respectively. In the diversity receiver that selects and outputs the detection output of the receiving system corresponding to the maximum detection level among the detection levels, the level detection characteristic of the level detector of each receiving system is the most A diversity receiver characterized by being shifted to the lower side along the reception input level axis with respect to the level detection characteristic of the level detector of the reception system having the worst sensitivity by the difference in sensitivity of the reception system with respect to the poor sensitivity. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61036579A JPH07105754B2 (en) | 1986-02-21 | 1986-02-21 | Diversity receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61036579A JPH07105754B2 (en) | 1986-02-21 | 1986-02-21 | Diversity receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62194748A JPS62194748A (en) | 1987-08-27 |
| JPH07105754B2 true JPH07105754B2 (en) | 1995-11-13 |
Family
ID=12473678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61036579A Expired - Lifetime JPH07105754B2 (en) | 1986-02-21 | 1986-02-21 | Diversity receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07105754B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04337931A (en) * | 1991-05-15 | 1992-11-25 | Nippon Telegr & Teleph Corp <Ntt> | Diversity reception system |
| JP4308288B2 (en) | 2007-09-10 | 2009-08-05 | 新日本製鐵株式会社 | Outlet structure of melting furnace and repair method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5542790B2 (en) * | 1975-01-09 | 1980-11-01 | ||
| JPS53120211A (en) * | 1977-03-29 | 1978-10-20 | Nec Corp | Signal detection circuit |
-
1986
- 1986-02-21 JP JP61036579A patent/JPH07105754B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| 昭和６１年度電子通信学会総合全国大会講演論文集分冊１０、昭和６１年３月５日、電子通信学会「２３６６ブランチ間偏差のあるダイバーシチ受信特性の検討」Ｐ．１０−９９ |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62194748A (en) | 1987-08-27 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |