JPS62196913A - Surface acoustic wave filter circuit - Google Patents
Surface acoustic wave filter circuitInfo
- Publication number
- JPS62196913A JPS62196913A JP3823086A JP3823086A JPS62196913A JP S62196913 A JPS62196913 A JP S62196913A JP 3823086 A JP3823086 A JP 3823086A JP 3823086 A JP3823086 A JP 3823086A JP S62196913 A JPS62196913 A JP S62196913A
- Authority
- JP
- Japan
- Prior art keywords
- wave
- vector
- surface acoustic
- acoustic wave
- input
- 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
- 238000010897 surface acoustic wave method Methods 0.000 title claims abstract description 25
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 230000002238 attenuated effect Effects 0.000 claims description 4
- 238000000034 method Methods 0.000 claims 1
- 239000013598 vector Substances 0.000 abstract description 35
- 230000002194 synthesizing effect Effects 0.000 abstract 2
- 230000002411 adverse Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 5
- 239000002131 composite material Substances 0.000 description 3
- 230000003111 delayed effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
Description
【発明の詳細な説明】 〔発明の技術分野〕 本発明は、弾性表面波フィルタ回路の改良に関する。[Detailed description of the invention] [Technical field of invention] The present invention relates to improvements in surface acoustic wave filter circuits.
従来、この種のフィルタは、第３図に示すような等価回
路１０として構成されていた。すなわち、入力端子１１
から入力された入力波は、減衰器１２で減衰され、帯域
フィルタ１３で濾波され、さらに遅延回路１４で遅延さ
れて、ベクトルＥ１４ををする波となり合成器１６に人
力される。Conventionally, this type of filter has been configured as an equivalent circuit 10 as shown in FIG. That is, the input terminal 11
The input wave inputted from the waveform is attenuated by an attenuator 12, filtered by a bandpass filter 13, and further delayed by a delay circuit 14 to become a wave having a vector E14 and inputted to a synthesizer 16.
一方入力波は、減衰器１５にも入力されて、第４図に示
す減衰されたベクトルＥＴ５を有する波となり合成器１
６に入力される。On the other hand, the input wave is also input to the attenuator 15 and becomes a wave having an attenuated vector ET5 shown in FIG.
6 is input.
上記合成器１６では、第４図に示すように、遅延された
ベクトルＥＴ４を基準ベクトルにして入出力結合による
干渉波のベクトルであるベクトルＥＴ５が遅延回路１４
によって入力波の周波数に比例した位相角で合成される
。そして、出力端子１７から合成ベクトルＩ−＋ｅを有
する波として出力されていた。In the synthesizer 16, as shown in FIG. 4, the delayed vector ET4 is used as a reference vector, and the vector ET5, which is a vector of interference waves due to input/output coupling, is transferred to the delay circuit 16.
is synthesized with a phase angle proportional to the frequency of the input wave. Then, it is outputted from the output terminal 17 as a wave having a composite vector I−+e.
ところが、このような等価回路では、前述したように減
衰器１２の固定損失および遅延回路１４の絶対遅延が大
きく、ベクトルＥ１５を有する干渉波は、ベクトルＥｉ
４を有する波に人力波の周波数に比例した位相角で合成
されるので、その結果合成ベクトルＥｉ６すなわち出力
波の振幅は、第５図の振幅周波数特性に示すように入力
波の周波数によってｒ （ｄＢ）の偏差を生じるという
問題点があった。この偏差は、伝送路上では遅延回路１
４の絶対遅延のために同一周波数干渉雑音となって、変
復調系に劣化をもたらす原因となっていた。However, in such an equivalent circuit, the fixed loss of the attenuator 12 and the absolute delay of the delay circuit 14 are large as described above, and the interference wave having the vector E15 is
4 with a phase angle proportional to the frequency of the human-powered wave, and as a result, the combined vector Ei6, that is, the amplitude of the output wave, depends on the frequency of the input wave as r ( There was a problem in that it caused a deviation of dB). This deviation is caused by the delay circuit 1 on the transmission path.
The absolute delay of 4 causes co-frequency interference noise, which causes deterioration in the modulation and demodulation system.
本発明は、上記問題点に鑑みなされたもので、偏差の生
じない良好な振幅周波数特性を存する弾性表面波フィル
タ回路を提供することを目的とする。The present invention has been made in view of the above problems, and an object of the present invention is to provide a surface acoustic wave filter circuit having good amplitude frequency characteristics without deviation.
本発明では、弾性表面波フィルタの入出力結合による干
渉波と逆位相の波を形成し、譲渡を前記弾性表面波フィ
ルタからの出力波に合成して前記入出力結合による干渉
波を打ち消すことによって上記目的を達成している。In the present invention, a wave having a phase opposite to the interference wave caused by the input/output coupling of the surface acoustic wave filter is formed, and the wave is combined with the output wave from the surface acoustic wave filter to cancel the interference wave caused by the input/output coupling. The above objectives have been achieved.
本発明の一実施例を第１図乃至第２図の図面に基づいて
詳細に説明する。An embodiment of the present invention will be described in detail based on the drawings of FIGS. 1 and 2.
第１図は、本発明の一実施例である弾性表面波フィルタ
回路の等価回路で、弾性表面波（ＳＡＷ）フィルタ１０
は第３図に示した弾性表面波フィルタ１０と同一の構成
となっている。FIG. 1 is an equivalent circuit of a surface acoustic wave filter circuit that is an embodiment of the present invention, and shows a surface acoustic wave (SAW) filter 10.
has the same structure as the surface acoustic wave filter 10 shown in FIG.
入力端子２１から入力されたベクトルＥ２２を冑する人
力波は分配器２２で二分され、一方の入力波は弾性表面
波フィルタ１０の入力端子１１から弾性表面波フィルタ
１０に入力され、ここで第４図に示したベクトルＥ１４
とベクトルＥＴ５との合成ベクトルＥ１６を有する波と
なって出力端子１７を介して合成器２５に入力される。The human power wave having the vector E22 inputted from the input terminal 21 is divided into two by the distributor 22, and one input wave is inputted to the surface acoustic wave filter 10 from the input terminal 11 of the surface acoustic wave filter 10, where the fourth Vector E14 shown in the figure
and vector ET5, resulting in a wave having a composite vector E16, which is input to the synthesizer 25 via the output terminal 17.
・ また分配器２２で二分された他方の人力波は、半固
定反転移相器２３で第２図に示すようにベクトルＥ２３
を有する波、即ち逆位相の波に反転され、さらに半固定
減衰器２４によってベクトルＥ１５と逆のベクトルＥ２
４を有する波に減衰されて合成器２５に人力される。- Also, the other human power wave divided into two by the distributor 22 is transformed into a vector E23 by the semi-fixed anti-transition phase shifter 23 as shown in FIG.
, that is, a wave with an opposite phase, and is further inverted by the semi-fixed attenuator 24 to a vector E2 opposite to the vector E15.
The resulting wave is attenuated into a wave having a wavelength of 4 and then input to the combiner 25 .
合成器２５では、弾性表面波フィルタ１０から入力され
たベクトルＥ１６を存する波と半固定減衰器２４から入
力されたベクトルＥ２４を有する波との合成が行なわれ
るが、ベクトルＥ１６はベクトルＥｉ４とベクトルＥｉ
５との合成ベクトルであるから、ベクトルＥ２４を有す
る波によってベクトルＥ１５を存する干渉波を打ち消す
ことができ、出力端子２６からベクトルＥＴ４を存する
波を出力させることができる。In the combiner 25, the wave having the vector E16 input from the surface acoustic wave filter 10 is combined with the wave having the vector E24 input from the semi-fixed attenuator 24, but the vector E16 is combined with the vector Ei4 and the vector Ei.
Since the wave having the vector E24 is a composite vector with the vector E24, the interference wave having the vector E15 can be canceled out, and the wave having the vector ET4 can be outputted from the output terminal 26.
したがって本発明の弾性表面波フィルタ回路は、干渉波
による偏差の生じない周波数特性を有することとなり、
同一周波数干渉雑音を低減させることができる。Therefore, the surface acoustic wave filter circuit of the present invention has frequency characteristics that do not cause deviations due to interference waves,
Co-frequency interference noise can be reduced.
以上説明したように、本発明では弾性表面波フィルタの
入出力結合による干渉波と逆位相の波を形成し、該波を
前記弾性表面波フィルタがらの出力波に合成して前記人
出力結合による干渉波を打ち消すようにした。そのため
、偏差の生じない良好な振幅周波数特性釘する弾性表面
波フィルタ回路を得ることができる。As explained above, in the present invention, a wave having a phase opposite to the interference wave due to the input/output coupling of the surface acoustic wave filter is formed, and this wave is combined with the output wave of the surface acoustic wave filter, and the wave is synthesized by the input/output coupling of the surface acoustic wave filter. I tried to cancel the interference waves. Therefore, it is possible to obtain a surface acoustic wave filter circuit with good amplitude-frequency characteristics without deviation.
第１図は本発明の一実施例を示すブロック図、第２図は
第１図に示した等価回路のベクトル図、第３図は弾性表
面波フィルタの等価回路を示すブロック図、第４図は第
３図示した等価回路より得られる波の有するベクトル図
、第５図は同じく第３図に示した等価回路の振幅周波数
特性を示す図である。
１０・・・弾性表面波フィルタ、１１．２１・・・入力
端子、１２．１５・・・減衰器、１３・・・フィルタ、
１４・・・遅延回路、１６．２５・・・合成器、１７゜
２６・・・出力端子、２２・・・分配器、２３・・・半
固定反転移相器、２４・・・半固定減衰器。FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a vector diagram of the equivalent circuit shown in FIG. 1, FIG. 3 is a block diagram showing the equivalent circuit of a surface acoustic wave filter, and FIG. is a vector diagram of a wave obtained from the equivalent circuit shown in FIG. 3, and FIG. 5 is a diagram showing the amplitude frequency characteristics of the equivalent circuit also shown in FIG. 3. 10... Surface acoustic wave filter, 11.21... Input terminal, 12.15... Attenuator, 13... Filter,
14...Delay circuit, 16.25...Synthesizer, 17゜26...Output terminal, 22...Distributor, 23...Semi-fixed anti-transition phase shifter, 24...Semi-fixed attenuation vessel.
Claims (1)
タの入出力結合による干渉波と逆位相の波を形成し、該
波を前記弾性表面波フィルタからの出力波に合成するこ
とを特徴とする弾性表面波フィルタ回路。The method is characterized in that the phase of the input wave is inverted and attenuated to form a wave having a phase opposite to the interference wave due to the input/output coupling of the surface acoustic wave filter, and the wave is combined with the output wave from the surface acoustic wave filter. surface acoustic wave filter circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3823086A JPS62196913A (en) | 1986-02-25 | 1986-02-25 | Surface acoustic wave filter circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3823086A JPS62196913A (en) | 1986-02-25 | 1986-02-25 | Surface acoustic wave filter circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62196913A true JPS62196913A (en) | 1987-08-31 |
Family
ID=12519502
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3823086A Pending JPS62196913A (en) | 1986-02-25 | 1986-02-25 | Surface acoustic wave filter circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62196913A (en) |
-
1986
- 1986-02-25 JP JP3823086A patent/JPS62196913A/en active Pending
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