JPS6120171B2 - - Google Patents
Info
- Publication number
- JPS6120171B2 JPS6120171B2 JP12381475A JP12381475A JPS6120171B2 JP S6120171 B2 JPS6120171 B2 JP S6120171B2 JP 12381475 A JP12381475 A JP 12381475A JP 12381475 A JP12381475 A JP 12381475A JP S6120171 B2 JPS6120171 B2 JP S6120171B2
- Authority
- JP
- Japan
- Prior art keywords
- filter
- resonators
- ladder
- damping capacity
- series
- 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
Links
- 238000013016 damping Methods 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezo-electric or electrostrictive material
- H03H9/58—Multiple crystal filters
- H03H9/60—Electric coupling means therefor
- H03H9/605—Electric coupling means therefor consisting of a ladder configuration
Description
【発明の詳細な説明】
この発明は複数個の圧電共振子を梯子型に接続
して構成した梯子型圧電フイルタに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ladder-type piezoelectric filter constructed by connecting a plurality of piezoelectric resonators in a ladder-type manner.
梯子型圧電フイルタは、通常、第１図に示すよ
うに直列共振子Rs1，Rs3…Rsoと並列共振子
Rp2，Rp4…Rpo-1とからなる。この場合、実際の
製造に当つては、直列共振子Rs1，Rs3…Rsoの制
動容量どうしを一定とし、並列共振子Rp2，Rp4
…Rpo-1の制動容量どうしも一定としたものを用
いて構成されるのが普通であつた。ところが、こ
の構成法では、通過帯域にリツプルが生じてしま
う。そのため、圧電共振子の制動容量の製造上の
バラツキ範囲（±10％以内）において、カツト・
アンド・ドライにより調整しリツプルの減少を図
ることが行なわれているが、リツプルの減少には
限界があつた。 A ladder-type piezoelectric filter usually consists of series resonators Rs 1 , Rs 3 ...Rs o and parallel resonators as shown in Figure 1.
It consists of Rp 2 , Rp 4 ...Rp o-1 . In this case, in actual manufacturing, the damping capacities of the series resonators Rs 1 , Rs 3 ... Rs o are constant, and the parallel resonators Rp 2 , Rp 4
...The braking capacity of Rp o-1 was usually constructed using a constant value. However, with this configuration method, ripples occur in the passband. Therefore, within the manufacturing variation range (within ±10%) of the damping capacity of the piezoelectric resonator, the cut
Although attempts have been made to reduce ripple by adjusting and drying, there is a limit to how much ripple can be reduced.
一方、影像パラメータ法を利用して共振子の制
動容量を理論的に決定する方法では、直列共振子
Rs1，Rs3…Rsoのうち、入出力端子に直接接続さ
れた直列共振子Rs1，Rsoの制動容量が残りの直
列共振子Rs3，Rs5…Rso-2の制動容量の２倍に設
定される。この方法によると、段数の少ない場合
は理論値どおりリツプルの小さい特性の良好なフ
イルタが得られるが、多段接続を行つたものでは
理論値との誤差が大きくなり、特に５段以上にな
ると通過帯域内のリツプルが増加し、フイルタ特
性が低下する。そのため、フイルタ特性を良好に
するためには、やはりカツト・アンド・トライの
調整を必要とする。また、入出力端子に直接接続
された直列共振子の制動容量が他の直列共振子の
制動容量の２倍と大きくなると、フイルタの減衰
量が小さくなつてしまう欠点がある。 On the other hand, in the method of theoretically determining the damping capacity of a resonator using the image parameter method, the series resonator
Of Rs 1 , Rs 3 ...Rs o , the damping capacity of the series resonators Rs 1 , Rs o directly connected to the input/output terminals is equal to the damping capacity of the remaining series resonators Rs 3 , Rs 5 ...Rs o-2. It is set to double. According to this method, when the number of stages is small, a filter with good characteristics with small ripple can be obtained as per the theoretical value, but when the number of stages is connected, the error from the theoretical value increases, and especially when the number of stages is 5 or more, the pass band The ripple within the filter increases, and the filter characteristics deteriorate. Therefore, in order to improve the filter characteristics, cut-and-try adjustments are still required. Furthermore, if the damping capacity of a series resonator directly connected to an input/output terminal is twice as large as the damping capacity of other series resonators, there is a drawback that the amount of attenuation of the filter becomes small.
更に制動容量を２倍にすることは、圧電体材料
を同じとした場合、面積を２倍にするか又は厚み
を1/2にすることを意味し、製造上の困難性を増
す。特に共振子をできるだけ薄くしてフイルタ全
体を小型にしようとする場合に、入出力端子部の
２個だけ他より更に1/2に薄くすることは、製造
上大きな困難をもたらす。 Furthermore, doubling the braking capacity means doubling the area or halving the thickness if the piezoelectric material is the same, which increases the difficulty in manufacturing. Particularly when trying to make the resonator as thin as possible to make the entire filter smaller, making only two of the input/output terminals 1/2 as thin as the others poses great manufacturing difficulties.
この発明は上記した点に鑑みてなされたもので
減衰量を小さくすることなく通過帯域内のリツプ
ルを減少させた梯子型圧電フイルタを提供するも
のである。 The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide a ladder-type piezoelectric filter that reduces ripples in the passband without reducing the amount of attenuation.
即ち、この発明は第１図に示すように複数個の
圧電共振子を梯子型に接続して構成した圧電フイ
ルタにおいて、入出力端子に直列接続された直列
共振子Rs1およびRsnの制動容量をCs′、他の直列
共振子Rs3，Rs5…Rso-2の制動容量をCsとしたと
き、1.5≦Cs′／Cs≦1.7を満たすようにしたこと
を特徴とする。 That is, in a piezoelectric filter constructed by connecting a plurality of piezoelectric resonators in a ladder shape as shown in FIG . When Cs is the damping capacity of Cs' and the other series resonators Rs 3 , Rs 5 .
上記した制動容量の範囲は実験的に求めたもの
で、その範囲を逸脱すると通過帯域内のリツプル
が実用上許容されない程度に大きくなるという根
拠に基づく。 The above-mentioned range of damping capacity was determined experimentally, and is based on the basis that if it deviates from this range, the ripple in the pass band becomes large to an extent that is not allowed in practice.
第２図は実験データで、第１図の並列共振子
Rp2，Rp4…Rpo-1の制動容量をCp＝500pF、直
列共振子Rs3，Rs5…Rso-2の制動容量をCs＝
61pFとし、入出力端子に直接接続された直列共
振子Rs1およびRsnの制動容量をCs′＝（１〜３）
Csの範囲で種々変えた場合の通過帯域特性を示
している。なお、段数は９段（即ちｎ＝９）とし
た場合のデータである。 Figure 2 shows experimental data for the parallel resonator shown in Figure 1.
Rp 2 , Rp 4 ...The damping capacitance of Rp o-1 is Cp = 500pF, and the damping capacitance of series resonators Rs 3 , Rs 5 ...Rs o-2 is Cs =
61 pF, and the damping capacitance of the series resonators Rs 1 and Rsn directly connected to the input and output terminals is Cs' = (1 to 3)
The passband characteristics are shown when various changes are made within the range of Cs. Note that the data is based on the case that the number of stages is 9 stages (that is, n=9).
第２図から明らかなように、Cs′＝（1.5〜1.7）
Csの範囲でリツプルの少ない良好な通過帯域特
性を示している。 As is clear from Figure 2, Cs′ = (1.5 to 1.7)
It shows good passband characteristics with little ripple in the Cs range.
第２図ではｎ＝９。Cp＝500pF、Cs＝61pFの
場合を示したが、本発明はｎが変化した場合でも
適用でき、またCp，Csが変化した場合でも適用
できる。このことを第３図乃至第９図を用いて説
明する。 In Figure 2, n=9. Although the case where Cp=500 pF and Cs=61 pF is shown, the present invention can be applied even when n changes, and even when Cp and Cs change. This will be explained using FIGS. 3 to 9.
第３図乃至第７図は、並列共振子Rp2，Rp4…
Rpo-1の制動容量と直列共振子Rs3，Rs5…Rso-2
の制動容量を、第２図の場合と同様に、夫々Cp
＝500pF、Cs＝61pFとし、段数をｎ＝５，７，
11，13，15と変化させていつた場合の通過帯域特
性の実験データを示している。これらの図からも
わかるように、段数が多くなるにつれて1.5≦
Cs′／Cs≦1.7の範囲でリツプルの少ない良好な
通過帯域特性が得られている。 3 to 7 show parallel resonators Rp 2 , Rp 4 . . .
Damping capacity of Rp o-1 and series resonator Rs 3 , Rs 5 …Rs o-2
As in the case of Fig. 2, the braking capacity of Cp
= 500pF, Cs = 61pF, and the number of stages is n = 5, 7,
It shows experimental data of the passband characteristics when the values were changed to 11, 13, and 15. As can be seen from these figures, as the number of stages increases, 1.5≦
Good passband characteristics with few ripples are obtained in the range of Cs'/Cs≦1.7.
やた第８図及び第９図はCpとCsを、インピー
ダンスＺが一定という条件を保ちながら変化させ
た場合の実験データを示している。即ち第８図は
Cp＝300pF、Cs＝101.7pFの場合、第９図はCp
＝700pF、Cs＝43.6pFの場合である。これらの
図からもわかるように、やはり1.5≦Cs′／Cs≦
1.7の範囲でリツプルの少ない良好な通過帯域特
性が得られている。 Figures 8 and 9 show experimental data when Cp and Cs were varied while keeping the impedance Z constant. That is, Figure 8 is
When Cp=300pF and Cs=101.7pF, Figure 9 shows Cp
= 700pF, Cs = 43.6pF. As can be seen from these figures, 1.5≦Cs′／Cs≦
Good passband characteristics with little ripple are obtained in the range of 1.7.
第１０図はCs′／Csを変化させた場合の455K
Hzｚにおける減衰量の変化の様子を示ており、
Cs′／Cs＝２の従来のものに比べ、本発明の1.5
≦Cs′／Cs≦1.7のフイルタの方が減衰量が大き
いことがわかる。 Figure 10 shows 455K when Cs′/Cs is changed.
It shows how the attenuation changes in Hz.
Compared to the conventional one with Cs'/Cs=2, the present invention's 1.5
It can be seen that the filter with ≦Cs′/Cs≦1.7 has a larger attenuation amount.
以上述べたように、この発明によれば、Cs′＝
Csとして、制動容量のバラツキの範囲内でカツ
ト・アンド・トライにより通過帯域特性の調整を
行つた従来のものに比べて、容易に特制の良好な
フイルタが構成できる。また、影像パラメータ法
を利用してCs′＝2Csとしたものよりもリツプル
は少なく、しかも減衰量も大きい。 As described above, according to this invention, Cs′=
As for Cs, a filter with good special control can be easily constructed compared to the conventional filter in which the passband characteristic is adjusted by cut-and-try within the range of variation in damping capacity. Moreover, the ripple is smaller than that using the image parameter method and Cs'=2Cs, and the amount of attenuation is also larger.
特にこの発明は、多段構成した場合に、減衰量
を小さくすることなく通過帯域内でのリツプルの
減少を図る上で非常に有効である。また、Cs′＝
2Csとする場合に比べて製造上の困難性が大幅に
軽減される。 In particular, the present invention is very effective in reducing ripples within the passband without reducing the amount of attenuation when a multi-stage configuration is used. Also, Cs′=
The difficulty in manufacturing is significantly reduced compared to the case of using 2Cs.
第１図は梯子型圧電フイルタの構成を示す図、
第２図乃至第９図はこの発明の効果を説明するた
めの実験データで、入出力端子に直接接続された
直列共振子の制動容量を種々変えて測定した通過
帯域特性を示す図、第１０図は減衰量の変化の様
子を示す図である。
Rs1，Rs3…Rso；直列共振子、Rp2，Rp4…
Rpo-1；並列共振子。
Figure 1 is a diagram showing the configuration of a ladder-type piezoelectric filter.
Figures 2 to 9 are experimental data for explaining the effects of the present invention; The figure is a diagram showing how the amount of attenuation changes. Rs 1 , Rs 3 …Rs o ; series resonator, Rp 2 , Rp 4 …
Rp o-1 ; Parallel resonator.
Claims (1)
した梯子型圧電フイルタにおいて、梯子型圧電フ
イルタの入出力端子に直接接続された直列共振子
の制動容量を他の直列共振子の制動容量の1.5〜
1.7倍に設定したことを特徴とする梯子型圧電フ
イルタ。1 In a ladder type piezoelectric filter configured by connecting multiple piezoelectric resonators in a ladder type, the damping capacity of the series resonator directly connected to the input/output terminal of the ladder type piezoelectric filter is equal to the damping capacity of the other series resonators. 1.5~
A ladder-type piezoelectric filter characterized by a 1.7x magnification.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12381475A JPS5248452A (en) | 1975-10-16 | 1975-10-16 | Ladder-type piezoelectric filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12381475A JPS5248452A (en) | 1975-10-16 | 1975-10-16 | Ladder-type piezoelectric filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5248452A JPS5248452A (en) | 1977-04-18 |
| JPS6120171B2 true JPS6120171B2 (en) | 1986-05-21 |
Family
ID=14869987
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12381475A Granted JPS5248452A (en) | 1975-10-16 | 1975-10-16 | Ladder-type piezoelectric filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5248452A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6325768Y2 (en) * | 1980-03-18 | 1988-07-13 | ||
| JPS57208713A (en) * | 1981-06-17 | 1982-12-21 | Pioneer Electronic Corp | Bias controlling circuit |
| WO1988004115A1 (en) * | 1986-11-21 | 1988-06-02 | Takafumi Kasai | Amplifier having a constant-current bias circuit |
| USRE40036E1 (en) | 1991-10-28 | 2008-01-29 | Fujitsu Limited | Surface acoustic wave filter |
| JP2800905B2 (en) | 1991-10-28 | 1998-09-21 | 富士通株式会社 | Surface acoustic wave filter |
| JP2000286676A (en) | 1999-03-31 | 2000-10-13 | Sanyo Electric Co Ltd | Surface acoustic wave filter |
-
1975
- 1975-10-16 JP JP12381475A patent/JPS5248452A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5248452A (en) | 1977-04-18 |
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