JPH04129303A - Method for controlling oscillation of crystal oscillating circuit - Google Patents
Method for controlling oscillation of crystal oscillating circuitInfo
- Publication number
- JPH04129303A JPH04129303A JP24893390A JP24893390A JPH04129303A JP H04129303 A JPH04129303 A JP H04129303A JP 24893390 A JP24893390 A JP 24893390A JP 24893390 A JP24893390 A JP 24893390A JP H04129303 A JPH04129303 A JP H04129303A
- Authority
- JP
- Japan
- Prior art keywords
- oscillation
- resistor
- oscillating circuit
- crystal
- oscillating
- 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
- 230000010355 oscillation Effects 0.000 title claims abstract description 65
- 239000013078 crystal Substances 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims description 10
- 230000005855 radiation Effects 0.000 abstract description 7
- 230000002542 deteriorative effect Effects 0.000 abstract description 4
- 239000011324 bead Substances 0.000 abstract description 2
- 230000001939 inductive effect Effects 0.000 abstract description 2
- 229910000859 α-Fe Inorganic materials 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000003203 everyday effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Landscapes
- Oscillators With Electromechanical Resonators (AREA)
Abstract
Description
【発明の詳細な説明】
〔概 要〕
マイコンあるいは時計などに使用される水晶発振回路の
発振動作制御方法に関し、
水晶発振周波数の高調波成分による電波障害の発生を防
止することを目的とし、
水晶発振回路に電源が投入され、その発振動作が安定し
た時点で、その発振振幅を制限しまたその発振波形をな
まらせるための抵抗またはリアクタンス素子を、水晶振
動子に接続するように構成される。[Detailed Description of the Invention] [Summary] Regarding a method for controlling the oscillation operation of a crystal oscillation circuit used in microcomputers or watches, the purpose of this invention is to prevent the occurrence of radio wave interference due to harmonic components of the crystal oscillation frequency. When the oscillation circuit is powered on and its oscillation operation becomes stable, a resistor or reactance element for limiting the oscillation amplitude and blunting the oscillation waveform is connected to the crystal resonator.
本発明はマイコンあるいは時計などクロックを必要とす
る機器に使用される水晶発振回路の発振動作制御方法に
関する。The present invention relates to a method for controlling the oscillation operation of a crystal oscillation circuit used in devices that require a clock, such as a microcomputer or a clock.
〔従来の技術および発明が解決しようとする課題〕従来
よりマイクロコンピュータなどが一般生活に使用される
に従がい、そのクロック周波数、もしくはその高調波成
分の輻射による電波障害が問題となっている。[Prior Art and Problems to be Solved by the Invention] As microcomputers and the like have been used in everyday life, radio interference due to their clock frequencies or the radiation of their harmonic components has become a problem.
本発明は、このクロック発振振幅を、水晶発振開始特性
を悪化させることなく低下させ、またその発振波形をな
まらせることにより、該電波障害の発生を防止し、それ
によって他の機器に妨害を与えることなく共存すること
を可能にしたものである。The present invention reduces the clock oscillation amplitude without deteriorating the crystal oscillation start characteristics and blunts the oscillation waveform, thereby preventing the occurrence of radio wave interference and thereby causing interference with other equipment. This made it possible for them to coexist without any problems.
［課題を解決するための手段〕
かかる課題を解決するために本発明によれば、水晶発振
回路に電源が投入され、その発振動作が安定した時点で
、その発振振幅を制限しまたその発振波形をなまらせる
ための抵抗またはリアクタンス素子を、水晶振動子に接
続するようにした水晶発振回路の発振動作制御方法が提
供される。[Means for Solving the Problems] In order to solve the problems, according to the present invention, when the crystal oscillation circuit is powered on and its oscillation operation becomes stable, its oscillation amplitude is limited and its oscillation waveform is A method for controlling the oscillation operation of a crystal oscillation circuit is provided, in which a resistor or a reactance element for blunting the oscillation is connected to a crystal resonator.
０作 用〕
実験によれば、水晶振動子に直列に抵抗もしくはリアク
タンス素子を挿入することにより、マイコンシステムな
どが発生する不要輻射の電界強度が低下することが分っ
ている。これは、発振振幅が小さくなったためと、発振
波形がなまり、基準発振周波数の高調波成分のパワース
ペクトラムが低下したためである。0 Effect] According to experiments, it has been found that by inserting a resistor or reactance element in series with a crystal resonator, the electric field strength of unnecessary radiation generated by a microcomputer system etc. can be reduced. This is because the oscillation amplitude has become smaller, the oscillation waveform has become duller, and the power spectrum of harmonic components of the reference oscillation frequency has lowered.
発振回路の発振子裕（発振のし易さ）は等価直列抵抗と
して与えられる。これは発振回路の水晶振動子が本来も
っている負性抵抗分を打ち消す外部抵抗値として与えら
れる。水晶振動子に抵抗を挿入することは、この等価直
列抵抗を増大させることになり、水晶振動子のアクティ
ビティの個体ばらつきにより、発振開始しない場合も考
えられる。The oscillator width (easiness of oscillation) of an oscillation circuit is given as an equivalent series resistance. This is given as an external resistance value that cancels out the negative resistance inherent in the crystal resonator of the oscillation circuit. Inserting a resistor into the crystal resonator increases this equivalent series resistance, and due to individual variations in the activity of the crystal resonator, oscillation may not start.
しかしながら、発振開始しないような高い抵抗値を有し
た抵抗素子を挿入した発振回路でも、発振のきっかけと
なる電気的パルスを与え、−旦発振を開始すると、この
ような高い抵抗値との組み合わせでも、以降発振は安定
して持続することが実験により確かめられた。However, even in an oscillation circuit in which a resistance element with a high resistance value that does not start oscillation is inserted, if an electrical pulse is applied that triggers oscillation, and once oscillation starts, even in combination with such a high resistance value, It was confirmed through experiments that the oscillation continued stably after that.
このため、発振開始時のみ、充分な発振余裕をもった状
態とし、発振安定後、該水晶振動子に直列に抵抗（例え
ば数百オーム程度）またはリアクタンス素子を接続する
ことより、発振開始特性を悪化させることなしに、不要
輻射成分を低減し電波障害の発生を防止することができ
る。For this reason, the oscillation start characteristics are controlled by providing sufficient oscillation margin only at the start of oscillation, and after oscillation stabilizes, by connecting a resistor (for example, about several hundred ohms) or a reactance element in series with the crystal resonator. It is possible to reduce unnecessary radiation components and prevent the occurrence of radio wave interference without causing any deterioration.
第１図（ａ）および（ｂ）は本発明方法を実験するため
のマイコン用水晶発振回路の構成を例示する図であって
、Ｏ２０は水晶振動子、■はインバータ、γ１は帰還用
の抵抗、Ｃ１およびＣ２は例えば外付けのコンデンサで
あって、これらにより水晶発振回路が構成される。第１
図（ａ）に示されるＲは該水晶振動子Ｏ８Ｃと直列に接
続された抵抗であって、該抵抗Ｒと並列に常閉型のアナ
ログスイッチＡＳが接続され、所定のポート出力がオン
とならない限り該アナログスイッチＡＳによって該抵抗
Ｒは短絡される。1(a) and (b) are diagrams illustrating the configuration of a crystal oscillation circuit for a microcomputer for testing the method of the present invention, in which O20 is a crystal oscillator, ■ is an inverter, and γ1 is a feedback resistor. , C1 and C2 are, for example, external capacitors, which constitute a crystal oscillation circuit. 1st
R shown in Figure (a) is a resistor connected in series with the crystal oscillator O8C, and a normally closed analog switch AS is connected in parallel with the resistor R, so that a predetermined port output is not turned on. As far as the analog switch AS is concerned, the resistor R is short-circuited.
これにより発振開始時には該アナログスイッチＡＳによ
り該抵抗Ｒを短絡し、充分な発振余裕をもった状態とす
る。このようにして該発振回路が発振を開始し、そのク
ロックでマイクロコンピュータの動作が始まるとそのプ
ログラムによって制御される所定のポート出力によって
該アナログスイッチＡＳを開き、該水晶振動子Ｏ８Ｃと
直列に例えば数百オームの抵抗Ｒが挿入される。なおこ
の抵抗Ｒの抵抗値は、上述したように発振開始特性を悪
化させることなしに、不要輻射成分を低減することを目
的として、適宜の値が設定される。As a result, at the start of oscillation, the analog switch AS short-circuits the resistor R, creating a state with sufficient oscillation margin. In this way, the oscillation circuit starts oscillating, and when the microcomputer starts operating with the clock, the analog switch AS is opened by a predetermined port output controlled by the program, and the analog switch AS is connected in series with the crystal oscillator O8C. A resistor R of several hundred ohms is inserted. Note that the resistance value of this resistor R is set to an appropriate value for the purpose of reducing unnecessary radiation components without deteriorating the oscillation start characteristics as described above.
第１図（ｂ）は上記抵抗Ｒの代りにフェライトビーズも
しくは所定の誘導性リアクタンス素子りを挿入したもの
で、その動作は上記第１図（ａ）の場合と同様である。In FIG. 1(b), a ferrite bead or a predetermined inductive reactance element is inserted in place of the resistor R, and its operation is the same as that in FIG. 1(a).
第２図は本発明方法によるマイコン用水晶発振回路の発
振開始時のタイミング図であって、まず時点ｔ１におい
てパワーオンとなると、発振回路が発振動作を開始し、
発振波形が次第に増幅される。そしてその発振波形が充
分に立上った時点ｔ２でマイコンのリセット端子の出力
レベルが例えばハイレベルとなってマイコン動作が開始
され、その後所定の初期設定動作などがなされた後、時
点ｔ３で所定のポート出力がオンとなって該アナログス
イッチＡｓを開く。FIG. 2 is a timing chart when the crystal oscillation circuit for a microcomputer starts oscillating according to the method of the present invention. First, when the power is turned on at time t1, the oscillation circuit starts oscillating.
The oscillation waveform is gradually amplified. Then, at time t2 when the oscillation waveform rises sufficiently, the output level of the reset terminal of the microcomputer becomes, for example, a high level and microcomputer operation is started.After that, after predetermined initial setting operations are performed, a predetermined value is reached at time t3. The port output of is turned on and the analog switch As is opened.
これにより該水晶振動子Ｏ８Ｃと直列に該抵抗Ｒもしく
は該リアクタンス素子りが接続され、それにより第２図
に示すように該発振回路の発振振幅をある程度低下させ
、またその発振波形をなまらせて、電波障害の発生が防
止される。As a result, the resistor R or the reactance element is connected in series with the crystal oscillator O8C, thereby lowering the oscillation amplitude of the oscillation circuit to some extent and blunting the oscillation waveform, as shown in FIG. , the occurrence of radio wave interference is prevented.
第３図は上記マイコンのリセット端子を含むリセット回
路の１例を示すもので、パワーオン時、抵抗Ｔ２を通し
てコンデンサＣ３が充電され、その充電電圧が所定の基
準電圧Ｖ ｒａｆを越した時点でコンパレータＣＯＭＰ
の出力が例えばハイレベルとなってリセットされ、以後
マイコン動作が開始される。なお図中、Ｄはダイオード
を示す。FIG. 3 shows an example of a reset circuit including the reset terminal of the microcomputer described above. When the power is turned on, a capacitor C3 is charged through a resistor T2, and when the charging voltage exceeds a predetermined reference voltage V raf, a comparator C3 is charged. COMP
The output becomes, for example, a high level and is reset, and thereafter the microcomputer operation is started. Note that in the figure, D indicates a diode.
本発明によれば、発振回路の発振開始特性を悪化させる
ことなしに、不要輻射成分を低減することができ、電波
障害の発生を防止することができる。According to the present invention, unnecessary radiation components can be reduced without deteriorating the oscillation start characteristics of the oscillation circuit, and the occurrence of radio interference can be prevented.
第１図は本発明方法を実施するためのマイコン用水晶発
振回路の構成を例示する図、
第２図は本発明方法によるマイコン用水晶発振回路の発
振開始時のタイミング図、
第３図はマイコンのリセット回路の１例を示す図である
。
く符号の説明）
ＯＳＣ・・・水晶振動子、
ＡＳ・・・アナログスイッチ、
Ｒ・・・抵抗、 Ｌ・・・リアクタンス素
子。
マイコンのリセット回路の１例を示す口笛３図
（ａ）
第１図
ＯＳＣ・・・水晶振動子
ＡＳ・・・アナログスイフ
Ｒ・・・抵 抗
Ｌ・・・リアクタンス素７
コン用水晶
チFig. 1 is a diagram illustrating the configuration of a crystal oscillation circuit for a microcomputer to implement the method of the present invention, Fig. 2 is a timing diagram at the start of oscillation of the crystal oscillation circuit for a microcomputer according to the method of the present invention, and Fig. 3 is a diagram illustrating the configuration of a crystal oscillation circuit for a microcomputer according to the method of the present invention. FIG. 3 is a diagram showing an example of a reset circuit of FIG. (Explanation of symbols) OSC...Crystal resonator, AS...Analog switch, R...Resistance, L...Reactance element. Whistle diagram 3 (a) showing an example of a microcomputer reset circuit Figure 1 OSC...Crystal resonator AS...Analog swift R...Resistor L...Reactance element 7 Crystal chip for computer
Claims (1)
定した時点で、その発振振幅を制限しまたその発振波形
をなまらせるための抵抗またはリアクタンス素子を、水
晶振動子に接続することを特徴とする水晶発振回路の発
振動作制御方法。1.When power is applied to the crystal oscillator circuit and its oscillation operation becomes stable, a resistor or reactance element is connected to the crystal oscillator to limit the oscillation amplitude and blunt the oscillation waveform. A method for controlling the oscillation operation of a crystal oscillation circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24893390A JPH04129303A (en) | 1990-09-20 | 1990-09-20 | Method for controlling oscillation of crystal oscillating circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24893390A JPH04129303A (en) | 1990-09-20 | 1990-09-20 | Method for controlling oscillation of crystal oscillating circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04129303A true JPH04129303A (en) | 1992-04-30 |
Family
ID=17185576
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24893390A Pending JPH04129303A (en) | 1990-09-20 | 1990-09-20 | Method for controlling oscillation of crystal oscillating circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04129303A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030037477A (en) * | 2001-11-05 | 2003-05-14 | 씨멘스 오토모티브 주식회사 | Oscillating apparatus for micom |
| US20110193569A1 (en) * | 2010-02-11 | 2011-08-11 | Landis+Gyr, Inc. | Oscillator Circuit with RF Suppression |
| US8674776B2 (en) | 2011-09-28 | 2014-03-18 | Seiko Epson Corporation | Oscillator circuit, oscillator, electronic apparatus, and activation method oscillator circuit |
-
1990
- 1990-09-20 JP JP24893390A patent/JPH04129303A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030037477A (en) * | 2001-11-05 | 2003-05-14 | 씨멘스 오토모티브 주식회사 | Oscillating apparatus for micom |
| US20110193569A1 (en) * | 2010-02-11 | 2011-08-11 | Landis+Gyr, Inc. | Oscillator Circuit with RF Suppression |
| US9869698B2 (en) * | 2010-02-11 | 2018-01-16 | Landis+Gyr Llc | Oscillator circuit with RF suppression |
| US8674776B2 (en) | 2011-09-28 | 2014-03-18 | Seiko Epson Corporation | Oscillator circuit, oscillator, electronic apparatus, and activation method oscillator circuit |
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