JPH02149106A - Digital temperature compensated oscillator - Google Patents
Digital temperature compensated oscillatorInfo
- Publication number
- JPH02149106A JPH02149106A JP30373488A JP30373488A JPH02149106A JP H02149106 A JPH02149106 A JP H02149106A JP 30373488 A JP30373488 A JP 30373488A JP 30373488 A JP30373488 A JP 30373488A JP H02149106 A JPH02149106 A JP H02149106A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- digital
- crystal resonator
- analog
- temperature compensation
- 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.)
- Granted
Links
- 239000013078 crystal Substances 0.000 claims abstract description 35
- 238000006243 chemical reaction Methods 0.000 claims abstract description 13
- 230000010355 oscillation Effects 0.000 claims description 12
- 238000010586 diagram Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Oscillators With Electromechanical Resonators (AREA)
Abstract
Description
【発明の詳細な説明】
(発明の技術分野)
本発明は、温度変化による発振周波数の変化をデジタル
的に補償するデジタル温度補償発振器に関する。DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a digital temperature compensated oscillator that digitally compensates for changes in oscillation frequency due to temperature changes.
(発明の技術的背景とその問題点)
近時、周波数、時間等の基準として水晶発振器が広く用
いられている。ところで水晶発振器に用いられる水晶振
動子は一般に温度係数を持ち、温度の変化によって周波
数も変化する。たとえば、数MHzないし十数MHz程
度の周波数で一般的なATカットの水晶振動子は、第3
図において曲線Aで示すような3次曲線状の温度係数を
示し、その変極点は26℃程度である。(Technical background of the invention and its problems) Recently, crystal oscillators have been widely used as standards for frequency, time, etc. Incidentally, a crystal resonator used in a crystal oscillator generally has a temperature coefficient, and its frequency changes with changes in temperature. For example, AT-cut crystal resonators, which are common at frequencies of several MHz to tens of MHz, are
In the figure, the temperature coefficient has a cubic curve shape as shown by curve A, and its inflection point is about 26°C.
一方、電子機器の高精度化がすすむにつれて水晶発振器
にあっても周波数の安定度に対する要求は厳しくなる傾
向にある。このような要求を満たす水晶発振器としては
発振回路を恒温槽に収納したものがあるが、恒温槽を用
いるために形状が大型化し、消費電力も大きく、・電源
の投入時に周波数が安定化するまでに時間がかかり、し
かも部品が70℃程度の比較的高温度にさらされるため
に信頼性にも問題がある。On the other hand, as electronic equipment becomes more precise, requirements for frequency stability tend to become stricter even for crystal oscillators. A crystal oscillator that meets these requirements has an oscillation circuit housed in a thermostatic chamber, but the use of a thermostatic chamber increases the size and power consumption, and it takes a long time until the frequency stabilizes when the power is turned on. It takes a long time to process, and there is also a reliability problem because the parts are exposed to a relatively high temperature of about 70°C.
このために、水晶振動子にサーミスタ等の温度検出素子
を接続してそのリアクタンスの変化によって温度補償を
行うものがある。しかしながらこのようなものでは上記
恒温槽を用いたものに比べて周波数安定度は10倍以上
悪くなる。For this purpose, some devices connect a temperature detection element such as a thermistor to a crystal resonator and perform temperature compensation by changing the reactance of the element. However, in such a device, the frequency stability is 10 times worse than that in the above-mentioned device using a constant temperature bath.
このために、たとえば第4図に示すような構成のデジタ
ル温度補償発振器が知られている。For this purpose, a digital temperature compensated oscillator having a configuration as shown in FIG. 4, for example, is known.
この発振器では温度センサ1の検出出力をアナログ−デ
ジタル変換器2でデジタル変換し、このデジタル出力に
よって記憶素子、すなわちメモリ3のアドレスを選択し
てアクセスする。In this oscillator, the detection output of the temperature sensor 1 is digitally converted by an analog-to-digital converter 2, and an address of a storage element, that is, a memory 3 is selected and accessed based on this digital output.
このメモリ3には予め温度変化による発振器の発振周波
数の変化を補償するためのデータを書き込んでおく。Data for compensating for changes in the oscillation frequency of the oscillator due to temperature changes is written in advance in this memory 3.
そしてメモリ3の出力データをデジタル−アナログ変換
器4に与えてアナログ信号に変換する。Then, the output data of the memory 3 is given to a digital-to-analog converter 4 to be converted into an analog signal.
そしてこのアナログ信号を電圧容量変換素子5、たとえ
ばバリキャップに印加してその静電容量を制御する。そ
してこの電圧容量変換素子5を発振回路7の水晶振動子
6に接続し、その発振周波数を微小に可変して温度補償
を行う。This analog signal is then applied to the voltage capacitance conversion element 5, for example a varicap, to control its capacitance. The voltage capacitance conversion element 5 is connected to the crystal resonator 6 of the oscillation circuit 7, and the oscillation frequency is minutely varied to perform temperature compensation.
ところで、このようなもので、たとえば第3図に曲線A
で示すような3次曲線状の温度特性を有するATカット
の水晶振動子の温度補償を行なうと、特に0℃以下の低
温部および40℃以上の高温部で補償量が増大し、しか
も補償量が大きい状態で滑らかに温度補償を行うために
は温度のステップも細かくする必要があり、この結果メ
モリに大容量のものを必要とする問題がある。By the way, with something like this, for example, curve A in Figure 3
When temperature compensation is performed on an AT-cut crystal resonator that has a cubic temperature characteristic as shown in , the amount of compensation increases especially in the low temperature region below 0°C and the high temperature region above 40°C, and the amount of compensation increases. In order to perform temperature compensation smoothly in a state where the temperature is large, it is necessary to make the temperature steps fine, and as a result, there is a problem that a large capacity memory is required.
(発明の目的)
本発明は、上記の事情に鑑みてなされたもので、少ない
メモリ容量で高精度に温度補償を行うことができるデジ
タル温度補償発振器を提供することを目的とするもので
ある。(Object of the Invention) The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a digital temperature compensation oscillator that can perform temperature compensation with high accuracy with a small memory capacity.
(発明の概要)
本発明は、温度センサの出力をアナログ−デジタル変換
器でデジタル変換して温度補償データを格納した記憶素
子のアドレスを選択し、この出力データをデジタル−ア
ナログ変換器でアナログ変換して水晶振動子に接続した
電圧容量変換素子を制御して温度補償を行うようにした
ものにおいて、上記水晶振動子は3次曲線状の温度特性
を有するATカットの水晶振動子と2次曲線状の温度特
性を有するBTカットの水晶振動子を組み合わせたこと
を特徴とするものである。(Summary of the Invention) The present invention converts the output of a temperature sensor into digital data using an analog-to-digital converter, selects the address of a memory element that stores temperature compensation data, and converts this output data into analog data using a digital-to-analog converter. In this device, temperature compensation is performed by controlling a voltage-capacitance conversion element connected to a crystal resonator, in which the crystal resonator is an AT-cut crystal resonator having a cubic curve-shaped temperature characteristic and a quadratic curve-shaped crystal resonator. It is characterized by a combination of a BT-cut crystal resonator having temperature characteristics similar to the above.
(実施例)
以下、本発明の一実施例を、第1図に示すブロック図を
参照して詳細に説明する。(Example) Hereinafter, an example of the present invention will be described in detail with reference to the block diagram shown in FIG.
図中11は、温度センサで、たとえば温度変化に応じて
抵抗値が変化するサーミスタである。そして12は温度
センサ11から検出温度に応じたアナログ信号の温度デ
ータを与えられるアナログ−デジタル変換器で、上記ア
ナログ信号を予め定めたと、ット数のデジタル信号の温
度データに変換する。In the figure, 11 is a temperature sensor, for example, a thermistor whose resistance value changes according to temperature changes. Reference numeral 12 denotes an analog-to-digital converter which is supplied with analog signal temperature data corresponding to the detected temperature from the temperature sensor 11, and converts the analog signal into a predetermined number of digital signal temperature data.
そし7で、このデジタル化した温度データによって記憶
素子13たとえばEP−ROMのアドレスを選択する。Then, in step 7, the address of the storage element 13, such as an EP-ROM, is selected based on the digitized temperature data.
このEP−ROM13の各アドレスには予め、上記温度
データに対応した温度補償データを格納している。しか
して選択したアドレスから読みだした温度補償データを
デジタル−アナログ変換器14に与えてアナログ変換し
て電圧容量変換素子15に印加してその静電容量を制御
する。この電圧容量変換素子15は水晶発振器17の水
晶振動子16に接続してその発振周波数を微小に可変し
、温度変化による発振周波数の変化を補償する。Temperature compensation data corresponding to the above-mentioned temperature data is stored in each address of this EP-ROM 13 in advance. The temperature compensation data read from the selected address is supplied to the digital-to-analog converter 14 for analog conversion and applied to the voltage capacitance conversion element 15 to control its capacitance. This voltage capacitance conversion element 15 is connected to the crystal resonator 16 of the crystal oscillator 17 to minutely vary its oscillation frequency, thereby compensating for changes in the oscillation frequency due to temperature changes.
なお、上記水晶振動子16は、たとえば第3図に曲線A
で示すような周波数温度特性のATカットの水晶振動子
であるAT板18aと、同図に曲線Bで示すようなりT
力・ントの水晶振動子であるBT板16bとを並列に接
続し、BT板の頂点温度は約−35℃とし、かつAT板
16aのインダクタンスに対するBT板16bのインダ
クタンスは約2倍として低温度域でAT板26aの共振
周波数からBT板の共振周波数への移行が円滑に行なわ
れるようにしている。Note that the crystal resonator 16 has a curve A in FIG. 3, for example.
The AT plate 18a, which is an AT-cut crystal resonator, has a frequency-temperature characteristic as shown in FIG.
The BT plate 16b, which is a crystal oscillator, is connected in parallel, and the peak temperature of the BT plate is approximately -35°C, and the inductance of the BT plate 16b is approximately twice that of the AT plate 16a, so that the temperature is low. The transition from the resonant frequency of the AT plate 26a to the resonant frequency of the BT plate is made smooth in the region.
なお第3図において曲線CはAT板16aを実際の発振
回路に接続した際の周波数温度特性を示し、曲線りはB
T板16bを実際の発振回路に接続した際の周波数温度
特性を示すものである。In addition, in FIG. 3, curve C shows the frequency temperature characteristic when the AT board 16a is connected to an actual oscillation circuit, and the curve B
It shows the frequency-temperature characteristics when the T-plate 16b is connected to an actual oscillation circuit.
さらに第3図において、曲線Eは上記AT板16aと、
BT板16hとを並列に接続した発振回路の周波数温度
特性を示し、領域Fはアナログ−デジタル変換器14の
出力で電圧容量変換素子15を制御した上記実施例のデ
ジタル温度補償発j辰器の周波数温度特性の周波数変動
範囲を示している。Further, in FIG. 3, the curve E indicates the AT plate 16a,
The frequency-temperature characteristics of the oscillation circuit connected in parallel with the BT board 16h are shown, and region F shows the frequency-temperature characteristics of the digital temperature-compensated oscillator of the above embodiment in which the voltage-capacitance conversion element 15 is controlled by the output of the analog-to-digital converter 14. It shows the frequency fluctuation range of frequency temperature characteristics.
このような構成であれば、水晶振動子16はATカット
の水晶振動子であるAT板16aとBTカットの水晶振
動子であるBT板16bとを並列に接続し、BT板の頂
点温度は約−35℃とし、かつAT板16aのインダク
タンスに対するBT板16bのインダクタンスは約2倍
として低温領域でAT板16aの共振周波数からBT板
の共振周波数への移行が円滑に行なわれるようにしてい
るので、たとえば第3図に示す曲線Cのように本質的に
40℃以下の中温域および低温域では比較的良好な温度
特性を得られ、たとえば−40℃〜60℃の範囲で±2
ppm程度の良好な周波数温度特性を得ることができ
る。With this configuration, the crystal oscillator 16 has an AT plate 16a, which is an AT-cut crystal oscillator, and a BT plate 16b, which is a BT-cut crystal oscillator, connected in parallel, and the peak temperature of the BT plate is approximately -35°C, and the inductance of the BT plate 16b is approximately twice the inductance of the AT plate 16a to ensure a smooth transition from the resonance frequency of the AT plate 16a to the resonance frequency of the BT plate in the low temperature region. For example, as shown in curve C shown in Fig. 3, relatively good temperature characteristics can be obtained essentially in the medium and low temperature ranges below 40°C, and for example, ±2 in the range of -40°C to 60°C.
Good frequency-temperature characteristics on the order of ppm can be obtained.
そして、比較的良好な周波数温度特性の得られる上記中
温域および低温域については粗に、周波数温度特性に悪
化する高温域については密にデジタル−アナログ変換器
の出力で温度補償を行うことによって、たとえば第3図
にFで示すように一40℃〜80℃の広い温度範囲で±
0. 5ppm以下の良好な周波数温度特性を得ること
ができ、しかも恒温槽等を用いるものに比して消費電力
も著しく低減することができる。 なお、本発明は上
記実施例に限定されるものではなく、上記実施例ではA
T板とBT板とを組み合わせて中・低温域の周波数温度
特性を予め補償するようにしたが、たとえば第2図に示
すように異なる頂点温度T1、T2、T3を有する3個
のBTカットの水晶振動子を組み合わせて予め周波数温
度特性を平坦化しておきここにデジタルメモリの出力に
よって温度補償を行うようにしてもよい。Then, by roughly performing temperature compensation with the output of the digital-to-analog converter for the medium temperature range and low temperature range where relatively good frequency-temperature characteristics can be obtained, and in the high-temperature range where frequency-temperature characteristics are deteriorated, finely. For example, as shown by F in Figure 3, ±
0. Good frequency-temperature characteristics of 5 ppm or less can be obtained, and power consumption can be significantly reduced compared to those using a constant temperature bath or the like. Note that the present invention is not limited to the above embodiments, and in the above embodiments, A
The T plate and the BT plate were combined to compensate for the frequency temperature characteristics in the medium and low temperature ranges, but for example, as shown in Fig. It is also possible to flatten the frequency-temperature characteristics in advance by combining a crystal oscillator, and then perform temperature compensation using the output of the digital memory.
(発明の効果)
以上詳述したように、本発明によればデジタル的に温度
補償を行う際に、予め水晶振動子の絹合せによって温度
補償を行うようにしたのでデジタル的な補償量を少なく
でき、それによってメモリの容量を少なくすることがで
きるデジタル温度補償発振器を提供することができる。(Effects of the Invention) As detailed above, according to the present invention, when temperature compensation is performed digitally, the temperature compensation is performed in advance by aligning the crystal oscillator, thereby reducing the amount of digital compensation. It is possible to provide a digital temperature compensated oscillator that can reduce memory capacity.
第1図は本発明の一実施例を示すブロック図、第2図は
本発明の他の実施例を説明する周波数温度特性の図、
第3図は本発明の周波数温度特性を説明する図、第4図
は従来のデジタル温度補償発振器のブロック図である。
l 3 φ
14 ・
15 φ
l 6 ・
6a
6b
l 7 ・
記憶素子
デジタル−アナログ変換器
電圧容量変換素子
水晶振動子
AT板
BT板
発振回路
11・・・・温度センサ
12・・・・アナログ−デジタル変換器第301FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a diagram of frequency-temperature characteristics explaining another embodiment of the present invention, and FIG. 3 is a diagram explaining frequency-temperature characteristics of the present invention. FIG. 4 is a block diagram of a conventional digital temperature compensated oscillator. l 3 φ 14 ・ 15 φ l 6 ・ 6a 6b l 7 ・Storage element Digital-analog converter Voltage capacitance conversion element Crystal resonator AT board BT board Oscillation circuit 11...Temperature sensor 12...Analog-digital Converter No. 301
Claims (1)
号に変換するアナログ−デジタル変換器と、 このアナログ−デジタル変換器のデジタル出力に対応し
たアドレスを選択されて予め格納した温度補償データを
出力する記憶素子と、 この記憶素子の出力データをアナログ信号に変換するデ
ジタル−アナログ変換器と、 このデジタル−アナログ変換器の出力に応じて容量を制
御される電圧容量変換素子と、 この電圧容量変換素子に接続した水晶振動子と、この水
晶振動子と共に発振器を構成する発振回路とを具備する
ものにおいて、 上記水晶振動子は3次曲線状の温度特性を有するATカ
ットの水晶振動子と2次曲線状の温度特性を有するBT
カットの水晶振動子を組み合わせたことを特徴とするデ
ジタル温度補償発振器。[Claims] A temperature sensor that detects temperature; an analog-digital converter that converts the output of the temperature sensor into a digital signal having a value corresponding to the detected value; and a digital output of the analog-digital converter. a memory element that selects an address and outputs temperature compensation data stored in advance; a digital-to-analog converter that converts the output data of this memory element into an analog signal; a voltage-capacitance conversion element that is controlled; a crystal resonator connected to the voltage-capacitance conversion element; and an oscillation circuit that constitutes an oscillator together with the crystal resonator, wherein the crystal resonator has a cubic curve shape. An AT-cut crystal resonator with temperature characteristics of , and a BT with quadratic temperature characteristics.
A digital temperature compensated oscillator featuring a combination of cut crystal resonators.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63303734A JP2931595B2 (en) | 1988-11-30 | 1988-11-30 | Digital temperature compensated oscillator |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63303734A JP2931595B2 (en) | 1988-11-30 | 1988-11-30 | Digital temperature compensated oscillator |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH02149106A true JPH02149106A (en) | 1990-06-07 |
JP2931595B2 JP2931595B2 (en) | 1999-08-09 |
Family
ID=17924626
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP63303734A Expired - Fee Related JP2931595B2 (en) | 1988-11-30 | 1988-11-30 | Digital temperature compensated oscillator |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2931595B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7126793B2 (en) | 2002-10-16 | 2006-10-24 | Samsung Electronics Co., Ltd. | Head drum assembly for a tape recorder |
US7387435B2 (en) * | 1999-12-10 | 2008-06-17 | Fujitsu Limited | Temperature sensor |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS53152548U (en) * | 1978-03-28 | 1978-12-01 | ||
JPS6085440U (en) * | 1983-11-18 | 1985-06-12 | キンセキ株式会社 | Digital temperature compensated piezoelectric oscillator |
-
1988
- 1988-11-30 JP JP63303734A patent/JP2931595B2/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS53152548U (en) * | 1978-03-28 | 1978-12-01 | ||
JPS6085440U (en) * | 1983-11-18 | 1985-06-12 | キンセキ株式会社 | Digital temperature compensated piezoelectric oscillator |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7387435B2 (en) * | 1999-12-10 | 2008-06-17 | Fujitsu Limited | Temperature sensor |
US7126793B2 (en) | 2002-10-16 | 2006-10-24 | Samsung Electronics Co., Ltd. | Head drum assembly for a tape recorder |
US7280318B2 (en) | 2002-10-16 | 2007-10-09 | Samsung Electronics Co., Ltd. | Head drum assembly for a tape recorder |
Also Published As
Publication number | Publication date |
---|---|
JP2931595B2 (en) | 1999-08-09 |
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