JPH053911B2 - - Google Patents
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- Publication number
- JPH053911B2 JPH053911B2 JP59243097A JP24309784A JPH053911B2 JP H053911 B2 JPH053911 B2 JP H053911B2 JP 59243097 A JP59243097 A JP 59243097A JP 24309784 A JP24309784 A JP 24309784A JP H053911 B2 JPH053911 B2 JP H053911B2
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- voltage
- circuit
- probe
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- 238000001514 detection method Methods 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 15
- 239000000523 sample Substances 0.000 description 22
- 238000010586 diagram Methods 0.000 description 8
- 230000001360 synchronised effect Effects 0.000 description 8
- 238000001727 in vivo Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000000691 measurement method Methods 0.000 description 4
- 238000009529 body temperature measurement Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000000284 extract Substances 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 206010028980 Neoplasm Diseases 0.000 description 1
- 210000004556 brain Anatomy 0.000 description 1
- 201000011510 cancer Diseases 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 210000001035 gastrointestinal tract Anatomy 0.000 description 1
- 238000000338 in vitro Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Description
【発明の詳細な説明】
(産業上の利用分野)
本発明は周波数の変動に対応してある物理量が
停留点をもつて変化するような素子或は回路等の
該停留点に於ける共振周波数検出方法に関する。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to the resonant frequency at a stationary point of an element or a circuit in which a certain physical quantity changes with a stationary point in response to frequency fluctuations. Regarding detection method.
(従来技術)
一般に、共振現象は自然界に広く存在するがこ
れは特に電気回路に於いては極めて重要な現象で
あつて種々様々な回路或は装置に多用されてい
る。(Prior Art) Resonance phenomena generally exist widely in the natural world, but they are particularly important phenomena in electric circuits, and are frequently used in a variety of circuits and devices.
従つて、これら電気回路或は回路素子等の共振
周波数を正確に測定することは不可欠の技術であ
るが一般に、共振回路は周囲環境の影響を受け易
く、周波数カウンター等の測定器の入力端子を直
接共振回路に接触せしめると周波数が変動し正確
な測定が不可能となることが多い。 Therefore, it is an essential technology to accurately measure the resonant frequency of these electric circuits or circuit elements, but in general, resonant circuits are easily affected by the surrounding environment, and the input terminal of a measuring device such as a frequency counter is If it comes into direct contact with a resonant circuit, the frequency will fluctuate and accurate measurement is often impossible.
従来、このような場合の共振周波数測定方法と
しては、これら被測定回路等の近傍に非接触に配
置した周波数可変発振器の発振エネルギーが前記
被測定共振回路と同一周波数に於いてこれに吸収
される現象を用いたもの、所謂デイツプ・メータ
法が一般的であつた。 Conventionally, the resonant frequency measurement method in such cases is to absorb the oscillation energy of a variable frequency oscillator placed non-contact near the resonant circuit under test at the same frequency as the resonant circuit under test. A method using phenomena, the so-called dip meter method, was common.
このデイツプ・メータの原理を少しく説明すれ
ば、第4図に示すように電圧計(V.V)1を付加
した周波数可変発振器2にこれと並列共振回路を
構成する如く接続したアンテナ・コイル3を例え
ばインダクタンスL1及びコンデンサC1とからな
る被測定回路4に接近せしめ前記発振器2の周波
数を1から2まで変化すれば前記コイル3の両端
に於ける周波数と前記電圧計の電圧とは第5図に
示す如く前記被測定回路の共振周波数0に於いて
前記電圧計の地が最小となるよう変化する。これ
は前述の通り、前記発振器2のエネルギーがこれ
よりインピーダンスの低い被測定共振回路に吸収
されるために生ずるものであつて測定者は電圧計
の針の振れが最小となるよう前記発振器2の周波
数を調整することによつてその点に於ける周波数
を検出することができる。 To briefly explain the principle of this dip meter, as shown in FIG. If the circuit under test 4 consisting of an inductance L 1 and a capacitor C 1 is approached and the frequency of the oscillator 2 is changed from 1 to 2 , the frequency at both ends of the coil 3 and the voltage of the voltmeter are as shown in FIG. As shown in the figure, the ground of the voltmeter changes to a minimum at the resonant frequency of the circuit under test, which is 0 . As mentioned above, this occurs because the energy of the oscillator 2 is absorbed by the resonant circuit under test, which has a lower impedance. By adjusting the frequency, the frequency at that point can be detected.
しかしながら、このような従来のレベルデイツ
プ法による共振周波数測定方法はレベル最小値或
はこれを電流変換して電流の最大値を検出するも
のであるから正確な測定が困難である。 However, such a conventional resonant frequency measurement method using the level dip method detects the minimum level value or converts this into a current to detect the maximum current value, and therefore accurate measurement is difficult.
即ち、上述のデイツプ点に於ける電圧最小値は
被測定共振回路の抵抗分とリアクタンスの比所謂
Q(quality factor)、或は該回路と前記アンテナ
コイル3との相互インダクタンス等によつて変化
するものであつて都度異るものであるから一義的
に特定が困難なため、測定制度に欠けると云う欠
陥があつた。 That is, the minimum voltage value at the dip point mentioned above changes depending on the ratio of the resistance and reactance of the resonant circuit to be measured, the so-called Q (quality factor), or the mutual inductance between the circuit and the antenna coil 3, etc. It is difficult to identify it unambiguously because it differs from case to case, so there was a flaw in the lack of a measurement system.
(発明の目的)
本発明は上述したような従来の共振周波数測定
方法の欠陥を解決するためになされたものであつ
て、測定条件と無関係に一義的に共振点を検出す
ることができしかも測定制度が極めて高い共振周
波数の検出方法を提供することを目的とする。(Object of the Invention) The present invention has been made in order to solve the deficiencies of the conventional resonance frequency measurement method as described above. The purpose of this invention is to provide a method for detecting resonant frequencies with extremely high precision.
(発明の構成)
上述の目的を達成するために本発明は以下の如
き構成をとる。(Structure of the Invention) In order to achieve the above-mentioned object, the present invention has the following structure.
即ち、被測定回路に所要の低周波信号によつて
周波数変調を施した搬送波信号を印加せしめると
共に、該搬送波信号が前記被測定回路の共振周波
数及びその近傍に於いて受ける振幅歪を復調する
ことによつて前記共振周波数を検出する如く構成
する。 That is, applying a carrier wave signal frequency-modulated by a required low frequency signal to the circuit under test, and demodulating the amplitude distortion that the carrier signal receives at the resonant frequency of the circuit under test and its vicinity. The resonant frequency is detected by the following.
(実施例)
以下本発明を図示した実施例に基づいて詳細に
説明する。(Example) The present invention will be described in detail below based on an illustrated example.
その前に、上述したような被接触にて非測定回
路等の共振周波数を測定する場合の具体例をあ
げ、従来のデイツプメータ法の欠点を少しく説明
する。 Before that, we will give a specific example of measuring the resonant frequency of a non-measuring circuit with a contact as described above, and briefly explain the drawbacks of the conventional dip meter method.
近年、生物学、医学上の研究等にガンの治療等
を目的として生体内各部の温度を測定する為長期
間生体内に埋込んだ無電源プローブと生体外の測
定器との間を有線にて接続することなしに測温す
る方法が提案されている。 In recent years, in order to measure the temperature of various parts of the body for the purpose of cancer treatment, etc. in biological and medical research, wires have been used to connect unpowered probes implanted in the body for long periods and measuring instruments outside the body. A method has been proposed to measure temperature without having to connect the device.
上述の如き測温方法としてはアンテナ・コイル
に水晶振動子を接続したプローブを生体内の所望
の位置に外科的に埋込むか或はこれを消化器内に
流すと共に生体外から所要周波数の電磁エネルギ
を放射し前記アンテナ・コイルを介して前記水晶
振動子に与えこれが共振する際のエネルギ吸収を
観測する方法、即ち上述のデイツプメータ法を用
い前記プローブの共振点を検出することによつて
体内温度を測定するのが一般的である。 The above-mentioned temperature measurement method involves surgically implanting a probe with a crystal oscillator connected to an antenna coil at a desired location within the body, or passing it into the digestive tract and injecting electromagnetic waves at the desired frequency from outside the body. A method of emitting energy and applying it to the crystal resonator via the antenna coil and observing the energy absorption when it resonates, that is, by detecting the resonance point of the probe using the dipmeter method described above, the internal temperature can be determined. It is common to measure
しかしながら、このように生体内に埋め込んだ
プローブと体外装置との結合は極めて疎であるう
え前述の如くデイツプ点に於ける最小レベル量は
測定条件によつて変動するから共振点の検出は非
常に困難を要するものであつた。 However, the coupling between the probe implanted in the living body and the external device is extremely loose, and as mentioned above, the minimum level at the dip point varies depending on the measurement conditions, so detection of the resonance point is extremely difficult. It was difficult.
このような欠点を除去するため、本実施例では
本発明の共振周波数検出方法を応用して以下の如
く構成した生体内温度測定方法とする。 In order to eliminate such drawbacks, in this embodiment, the resonant frequency detection method of the present invention is applied to provide an in-vivo temperature measurement method configured as follows.
即ち、第1図は本発明に係かる生体内温度測定
装置の一実施例を示すブロツク図である。 That is, FIG. 1 is a block diagram showing one embodiment of the in-vivo temperature measuring device according to the present invention.
同図に於いて5は水晶発振子Xとアンテナ・コ
イルL3とで構成した生体内プローブであつて、
生体外装置として前記プローブと対向せしめたア
ンテナ・コイルL4に低周波発振器6の出力によ
りFM又はPM変調を施した電圧制御発振器
(VCO)7の出力を印加すると共に、前記アンテ
ナ・コイルL4にAM検波回路8を付加しその出力
を増幅器9を介して前記低周波発振器6の出力を
同期信号とする同期検波回路10に入力せしめか
つその出力でもつて前記VCO7の発振周波数を
制御する如く構成したものである。 In the figure, 5 is an in-vivo probe composed of a crystal oscillator X and an antenna coil L3 ,
As an in vitro device, the output of a voltage controlled oscillator (VCO) 7 subjected to FM or PM modulation using the output of a low frequency oscillator 6 is applied to the antenna coil L 4 facing the probe, and the antenna coil L 4 An AM detection circuit 8 is added to the synchronous detection circuit 8, the output of which is inputted via an amplifier 9 to a synchronous detection circuit 10 which uses the output of the low frequency oscillator 6 as a synchronous signal, and the oscillation frequency of the VCO 7 is controlled by the output thereof. This is what I did.
このように構成した生体内温度測定装置は以下
の如く動作する。 The in-vivo temperature measuring device configured as described above operates as follows.
即ち、第2図は前記プローブの共振周波数0近
傍に於いて照射電磁波が受けるAM変調歪の状態
を示す波形図である。 That is, FIG. 2 is a waveform diagram showing the state of AM modulation distortion that the irradiated electromagnetic wave is subjected to in the vicinity of the resonant frequency 0 of the probe.
今、前記低周波信号を80Hz、周波数偏位を±
2KHz電磁波周波数を19MHzから21MHzまで可変
とし前記プローブの共振周波数を□0=20MHzと
すると、前記周波数変調を受けた電磁波をその中
心周波数から±2KHzにわたつて80Hzの周期で振
動する。 Now, the low frequency signal is 80Hz, and the frequency deviation is ±
When the 2KHz electromagnetic wave frequency is variable from 19MHz to 21MHz and the resonant frequency of the probe is □ 0 =20MHz, the frequency-modulated electromagnetic wave is vibrated at a period of 80Hz over ±2KHz from its center frequency.
従つて、その中心周波数が前記プローブの共振
特性曲線上をその共振点0を含んでこれより△
低い点イ、0と同一点ロ及び△高い点ハの三つ
の点に位置する場合のAM変調歪は夫々同図中矢
印にて示したような波形を呈する。 Therefore, the center frequency is △ on the resonance characteristic curve of the probe including the resonance point 0 .
The AM modulation distortion when located at three points: a low point A, a point B that is the same as 0 , and a high point C exhibits waveforms as shown by the arrows in the figure, respectively.
即ち、前記電磁波の偏位周波数中にプローブの
共振点0を包含する場合、該共振点を境にその偏
位周波数の2倍のAM変調歪を生ずる。この2倍
歪は0の上下に於いて180°位相が異なり電磁波の
中心周波数が0と一致するとき前述の2倍歪は直
流的にはシフトしているがほヾ正弦波となる。 That is, when the resonance point 0 of the probe is included in the deflection frequency of the electromagnetic wave, AM modulation distortion twice as high as the deflection frequency occurs with the resonance point as a boundary. This double distortion has a phase difference of 180° above and below 0 , and when the center frequency of the electromagnetic wave coincides with 0 , the double distortion described above is shifted in terms of direct current, but becomes a sine wave.
これは前記プローブの共振回路に電磁エネルギ
ーが吸収されるためで、このときプローブに対向
した外部装置のコイルL4の両端には第3図c,
d,eに示すようなAM変調をうけた波形が現れ
る。 This is because the electromagnetic energy is absorbed by the resonant circuit of the probe, and at this time, both ends of the coil L4 of the external device facing the probe are
AM modulated waveforms as shown in d and e appear.
第3図は前記第1図に示したブロツク図の各部
の信号波形を示したものであつてaは低周波発振
器6の波形、bは該低周波信号によつてFM変調
をうけた電磁波でコイルL4に印加される信号波
形、c,d及びeは夫々前記第2図に示したプロ
ーブ共振特性曲線イ,ロ及びハに於ける前記コイ
ルL4両端に生ずる波形である。 FIG. 3 shows the signal waveforms of each part of the block diagram shown in FIG. The signal waveforms c, d, and e applied to the coil L4 are the waveforms generated at both ends of the coil L4 in the probe resonance characteristic curves A, B, and C shown in FIG. 2, respectively.
更にこれらc,d,eの波形をAM検波すると
夫々同図f,g,hに示す如く、前記プローブに
エネルギ吸収された結果生じた前述のAM変調成
分が抽出される。 Furthermore, when these waveforms c, d, and e are subjected to AM detection, the aforementioned AM modulation components generated as a result of energy absorption by the probe are extracted, as shown in f, g, and h of the figure, respectively.
従つてこの変化を何等かの手段によつて検出す
れば、そのときの電磁波の中心周波数が前記プロ
ーブの共振特性曲線上のどの点に位置するかが識
別できる。 Therefore, by detecting this change by some means, it is possible to identify at which point on the resonance characteristic curve of the probe the center frequency of the electromagnetic wave at that time is located.
本実施例では、このようにして復調した波形を
同期検波数回路10に於いて、前記低周波信号を
基準として同期検波したのち波形成形して第3図
i,j,kに示す如く夫々のAM変調歪に対応し
た矩形波を得、該矩形波のデユーテイ比を検出す
る如く構成し、前記プローブの共振点0に於ける
該デユーテイ比が1:1となることを利用してそ
のとき周波数を検出し、もつて生体内の温度を測
定するものである。 In this embodiment, the thus demodulated waveform is subjected to synchronous detection using the low frequency signal as a reference in the synchronous detection circuit 10, and then the waveform is shaped into the respective waveforms as shown in FIG. 3 i, j, and k. A rectangular wave corresponding to AM modulation distortion is obtained, the duty ratio of the rectangular wave is detected, and the duty ratio at the resonance point 0 of the probe is 1:1. It is used to detect and measure the temperature inside the living body.
更に、前記矩形波を積分したのち直流電圧に変
換すれば前述のデユーテイ比に対応した直流電圧
を得しかもこれは前記プローブの共振特性曲線上
の各点に一対一に対応した値となる。 Further, if the rectangular wave is integrated and then converted into a DC voltage, a DC voltage corresponding to the above-mentioned duty ratio is obtained, and this value corresponds one-to-one to each point on the resonance characteristic curve of the probe.
即ち、0に於いて相対値が0.5Vとなり0より低
い方で0.5V以下にかつ高い方でも0.5V以上とな
る。 That is, at 0 , the relative value is 0.5V, the lower side than 0 is 0.5V or less, and the higher side is 0.5V or more.
従つて上述の直流電圧を前記VCOの周波数制
御電圧を制御するよう構成すればこれら各ブロツ
クは閉ループを形成し前記電磁波の中心周波数を
プローブの共振点0に自動的に調整することが可
能となる。 Therefore, if the above-mentioned DC voltage is configured to control the frequency control voltage of the VCO, each of these blocks forms a closed loop, and the center frequency of the electromagnetic wave can be automatically adjusted to the resonance point 0 of the probe. .
つまり前述の直流電圧が0.5Vになるように又
は、この直流電圧出力を0.5Vを基準電圧とした
比較器に入力しその差が0となる如く前記閉ルー
プを作動せしめればサーボ制御ループ系を構成す
ることができ、これを利用して前記プローブの共
振点0が温度に従つて移動する際にその周波数の
自動測定を行なうことができる。 In other words, if the closed loop is operated so that the aforementioned DC voltage is 0.5V, or this DC voltage output is input to a comparator with 0.5V as the reference voltage, and the difference becomes 0, the servo control loop system can be activated. This can be used to automatically measure the frequency of the resonance point 0 of the probe as it moves in accordance with the temperature.
このように本発明を用いてロツクループ系を構
成すれば、従来のフエーズロツクループ(PLL)
を用いたものと比較して次のような特徴をもつ。 If a lock loop system is constructed using the present invention in this way, it will be possible to construct a lock loop system using the present invention.
It has the following characteristics compared to the one using .
即ち、従来のPLLが閉ループ中で信号の位相
を検出しその差を直流信号に変換してサーボ系を
構成するものであつて、一般に位相情報を抽出す
るには大きいレベルの信号を要するのに対し、本
発明はFM波に生ずるAM歪を抽出するものであ
るから比較的低レベル信号であつてもこれが可能
である。 In other words, a conventional PLL detects the phase of a signal in a closed loop and converts the difference into a DC signal to construct a servo system, and generally a large level signal is required to extract phase information. On the other hand, since the present invention extracts AM distortion occurring in FM waves, this is possible even with relatively low level signals.
又、両者のループ感度及びロツクレンジを比較
すれば、PLLに於いては周波数可変範囲全域例
えば2MHzをフルスケールとしてその中の極めて
狭い位相範囲例えば数KHzにロツクインせしめる
からロツクレンジとフルスケールの相対比は非常
に大きく、系を構成する回路素子等の安定性が系
の安定性は大きく左右するのに対し、本発明では
上述の周波数偏位例えば±2KHzがフルスケース
であつてその中の変調信号周波数の2倍例えば
160Hzを抽出するか或は波形のデユーテイ比1:
1を検出すれば足り前述のロツクレンジとフルス
ケール比は小さくなり、従来のPLLに比して系
の制御が極めて容易であることが理解できよう。 Also, if you compare the loop sensitivity and lock range of the two, the relative ratio of the lock range and full scale is The stability of the system is greatly influenced by the stability of the circuit elements that make up the system, but in the present invention, the above-mentioned frequency deviation, for example ±2KHz, is the full scale, and the modulation signal frequency within that 2 times for example
Extract 160Hz or waveform duty ratio 1:
It is sufficient to detect 1, and the aforementioned lock range and full scale ratio become small, and it can be understood that the control of the system is extremely easy compared to the conventional PLL.
尚上記実施例は本発明の一具体例であつてこれ
に限定されることはなく他に様々な実施方法があ
ること明らかである。例えば前記低周波信号は三
角波形の如く左右対象波であればよいし、又前記
同期検波回路も同期をとつた位相検波回路として
もよい。 It should be noted that the above embodiment is one specific example of the present invention, and the present invention is not limited thereto, and it is clear that there are various other implementation methods. For example, the low frequency signal may be a left-right symmetrical wave such as a triangular waveform, and the synchronous detection circuit may also be a synchronized phase detection circuit.
更に、本発明は被測定回路の共振周波数の検出
にとどまらずその特性が極大極小値の停留点(ス
テーシヨン・ポイント)をもつて変化するとき該
変化を周波数の変化に置換せしめればどのような
もの、例えばインピーダンスの停留点或は電流、
電圧の変化又はその他の物理変化のあらゆる停留
点検出に応用可能なること明らかであろう。 Furthermore, the present invention is not limited to detecting the resonant frequency of a circuit under test, but also detects what happens when the characteristic changes with a stationary point of maximum or minimum value and that change is replaced with a change in frequency. something, such as a stopping point of impedance or current,
It will be obvious that the invention can be applied to any stationary point detection of voltage changes or other physical changes.
本発明の他の応用例としては、例えば圧力によ
つて共振周波数が変化する素子或は回路を前記プ
ローブとなし前記実施例に示したブロツク図と同
様に構成した装置を用いてその共振周波数を検出
すれば上述の説明と同一の方法によつて圧力の検
出が可能であり、このようにすれば前記生体内の
温度測定と同様に生体内各部の圧力例えば脳内圧
力の測定或は容器内圧力の測定等に極めて有効で
ある。 As another application example of the present invention, for example, an element or a circuit whose resonant frequency changes depending on pressure is used as the probe, and the resonant frequency is adjusted using a device configured similarly to the block diagram shown in the above embodiment. If detected, the pressure can be detected by the same method as explained above, and in this way, in the same way as the temperature measurement in the living body, the pressure in various parts of the living body, such as the pressure in the brain, or the pressure inside the container can be measured. Extremely effective for measuring pressure, etc.
又、上述の例では共振回路のデイツプ点を検出
する場合を示したが、本発明はこれに限らず物理
量の変化の極大点を検出することも可能である。
このときは前記外部回路のアンテナコイルとAM
検波回路とを直列共振せしめそのインピーダンス
を低くすれば被測定回路が呈する物理量変化の極
大点を検出することができる。 Further, although the above example shows a case where a dip point of a resonant circuit is detected, the present invention is not limited to this, and it is also possible to detect a maximum point of a change in a physical quantity.
At this time, the antenna coil of the external circuit and the AM
By making the detection circuit resonate in series and lowering its impedance, it is possible to detect the maximum point of the physical quantity change exhibited by the circuit under test.
(発明の効果)
本発明は以上説明した如く構成し機能するもの
であるから周波数変動に対応してある物理量が停
留点をもつて変化する際の該貯留点に於ける周波
数を精密に検出する手段に適し、更にこの検出の
自動化をはかるうえで極めて都合がよい。(Effects of the Invention) Since the present invention is configured and functions as explained above, when a certain physical quantity changes with a stationary point in response to frequency fluctuation, the frequency at the storage point can be precisely detected. This method is suitable for various methods, and is extremely convenient for automating this detection.
殊に、生体内の温度或は圧力を測定する際の体
内埋込みプローブから温度情報を抽出する場合の
如く、物理変化の情報が微弱な場合これを正確に
検出するうえで極めて大きな効果がある。 In particular, it is extremely effective in accurately detecting weak information on physical changes, such as when extracting temperature information from an implanted probe for measuring temperature or pressure inside a living body.
第1図は本発明の一実施例を示すブロツク図、
第2図及び第3図は前記第1図に示したブロツク
図の各部の動作を説明するための波形図、第4図
及び第5図は共に従来の共振周波数測定方法を示
す原理図である。
1……電圧計、2……発振器、3……アンテ
ナ・コイル、4……被測定回路、5……プロー
ブ、6……低周波発振器、7……電圧制御発振回
路(VCO)、8……AM検波回路、9……増幅
器、10……同期検波回路、11……デユーテイ
比検出回路。
FIG. 1 is a block diagram showing one embodiment of the present invention;
Figures 2 and 3 are waveform diagrams for explaining the operation of each part of the block diagram shown in Figure 1, and Figures 4 and 5 are principle diagrams showing the conventional resonant frequency measurement method. . DESCRIPTION OF SYMBOLS 1... Voltmeter, 2... Oscillator, 3... Antenna coil, 4... Circuit under test, 5... Probe, 6... Low frequency oscillator, 7... Voltage controlled oscillator circuit (VCO), 8... ...AM detection circuit, 9...amplifier, 10...synchronous detection circuit, 11...duty ratio detection circuit.
Claims (1)
ピーダンス等物理量の変化が停留点を有する素子
或いは回路等の該停留点に於ける周波数を検出す
る際所要の信号によつて周波数変調を施した搬送
波信号をアンテナコイルを介して前記素子或いは
回路にワイヤレスにて関与せしめつつ前記搬送波
信号の中心周波数を変化したとき前記停留点に於
ける前記搬送波復調波形のデユーテイ比を抽出す
ることによつて前記停留点の周波数を検出するよ
うにしたことを特徴とする共振周波数の検出方
法。 2 前記搬送波復調波形を矩形波に変換しこれを
積分したのち直流電圧に変換することによつて前
記停留点の周波数を検出するようにしたことを特
徴とする特許請求の範囲1記載の共振周波数の検
出方法。 3 前記直流電圧によつて前記搬送波信号の中心
周波数を制御するよう閉ループを構成することに
よつて前記停留点の周波数を自動的に検出するよ
うにしたことを特徴とする特許請求の範囲2記載
の共振周波数の検出方法。[Claims] 1. When detecting the frequency at a stopping point of an element or circuit, etc., in which a change in a physical quantity such as voltage, current, or impedance has a stopping point in response to a change in frequency, the frequency can be determined by using a required signal. Extracting the duty ratio of the carrier demodulated waveform at the stopping point when the center frequency of the carrier signal is changed while causing the modulated carrier signal to be wirelessly connected to the element or circuit via an antenna coil. A method for detecting a resonant frequency, characterized in that the frequency at the stationary point is detected by: 2. The resonant frequency according to claim 1, wherein the frequency of the stationary point is detected by converting the carrier demodulated waveform into a rectangular wave, integrating this, and converting it into a DC voltage. Detection method. 3. Claim 2, characterized in that the frequency of the stationary point is automatically detected by configuring a closed loop so that the center frequency of the carrier signal is controlled by the DC voltage. How to detect the resonant frequency of.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP24309784A JPS61120974A (en) | 1984-11-16 | 1984-11-16 | Detection of resonance frequency |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP24309784A JPS61120974A (en) | 1984-11-16 | 1984-11-16 | Detection of resonance frequency |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS61120974A JPS61120974A (en) | 1986-06-09 |
JPH053911B2 true JPH053911B2 (en) | 1993-01-18 |
Family
ID=17098742
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP24309784A Granted JPS61120974A (en) | 1984-11-16 | 1984-11-16 | Detection of resonance frequency |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS61120974A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07242234A (en) * | 1994-03-07 | 1995-09-19 | Tanikei Seisakusho:Kk | Easily openable container lid |
JP2011137737A (en) * | 2009-12-28 | 2011-07-14 | Fukuda Crystal Laboratory | Wireless measurement device and wireless temperature measurement system |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5017872A (en) * | 1973-06-15 | 1975-02-25 |
-
1984
- 1984-11-16 JP JP24309784A patent/JPS61120974A/en active Granted
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5017872A (en) * | 1973-06-15 | 1975-02-25 |
Also Published As
Publication number | Publication date |
---|---|
JPS61120974A (en) | 1986-06-09 |
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