200914845 九、發明說明： 【發明所屬之技術領域】 本發明關於一種掃猫方法，用於測定一種大致正弦、、皮 形的信號走勢的相位；該信號走勢具有一基本頻率，且該 #號走勢利用基本頻率的泛波扭曲（失真化），其中藉著 用一掃瞒頻率fs掃瞄測定該信號走勢的一週期内的數個婦 瞒值，且由此計算出該相位。 r200914845 IX. Description of the Invention: [Technical Field] The present invention relates to a method for sweeping a cat for determining a phase of a substantially sinusoidal, pico-shaped signal; the signal has a basic frequency, and the ## trend The pan-wave distortion (distortion) of the fundamental frequency is utilized, in which a plurality of women's and women's values in the period of the signal are measured by a sweep frequency fs, and the phase is calculated therefrom. r
V 【先前技術】 舉例而言，這類掃瞄方法用於作訊息技術或在干涉計 測量目的。所謂的Nyquist_Shann〇n掃瞄理論或WKs取 樣里。冊（用於 Whittaker-Kotelnikow-Shannon)。係訊•技 術、信號處理與資訊理論的基本原理、掃瞄理論提到：— 種連續，㈣受限的信號〔最小頻率〇赫，最大頻率fmax〕 貝用大於2xfmax的頻率掃瞒，俾能由如此所得的時間不 :信號重建最初信號而無資訊損失，但要用無限大的成 ，或者用有P艮成本任意準確的趨近。在—般的情形對於 知瞄頻率（取樣頻率）fs適用下式（1): 0) fS>2(fmax—fmin)(對於 w>〇 赫) 實際上，該掃瞄理論表示： 出最大的頻率，舉例”，將一=在知晦則須知悉或找 立輦八妍H ^ ° 、用尚頻掃瞄的信號利用傳 立業为析，且如果我們I腺& & 要將此信號作良好趨近方式以# 建，則該信號須用多於雙枰 处万式以重 夕於又倍的頻率㈣（ 200914845 的目的）。所要掃瞄的信號的限制頻率（它可利用掃晦頻 率無誤地重建）稱為Nyquist頻率fN，且相當於一半的掃晦 頻率ff。 在實用上往往有一目的：把利用合諧的泛波 (Oberschwingung，英：overtone )扭曲（失真化） (Verzerren ’英：distorsion )的正弦波形信號利用數位計 算方法解除扭曲（entzerren ) ^因此本發明的目的在提供一 種快速的掃瞄方法，它一方面可維持高精確度，但也可簡 單地在今日電腦系統中實施（implementieren)。 【發明内容】 此目的達成之道係為：該信號走勢的至少一基本頻率 的相位與該泛波的相位藉著將下方或上方的泛波排除而 且同時測定。在此方法中的有利點為將計算限於簡單地得 到差或商，廷些方式在今曰電腦可簡單廉價地實施。因此 可迅速且較簡單地測定如此扭曲的信號的相位。 一種特別有利的方法變更例係為該㈣頻率Μ在一頻 率實施，使得一個相每於— 89 ' 半掃瞄頻率的尼奎斯特 C Myquist )限制頻率f 丨 ^ ^ 相虽於要排除的最大泛波的兩 ^ ^ 艾炅例中，在掃瞄頻率fs時β =亥t唬走勢的一週期選設掃 頻率f砗@U 怦田的數目，此數目小於在掃的 、 s寸里0冊上可能的掃瞄點沾 ig ΛΑ _ ^ ^ ，，的數目，且沿信號走勢的- k /月的一個知目田點之 1的寺間的間隔不同，其中二個先種 200914845 相隨的掃晦點的最小時間間隔由掃晦頻率&預設。如此， 所要實施的計算步驟減少到最少。 如果沿該信號走勢的-週期掃猫後，將掃猫點利用— ㈣猫移動作業移動-段最小時間間隔，_隔由掃晦頻 率fs決定，並測定信號走勢的新週期内的新的掃⑭ 相位測定可在不同掃㈣實施，這些掃H方面有利於 較大的累贅（Redundanz)且提高準確度，如果在此，該掃 瞄移動作業對應於在掃瞄頻_ fs時在信號走勢的一週期内 可能的掃晦點的數目作重複’且由所測定的相位值就算相 位平均值’則如此在相位測定時，統計學上的誤 減少。 人 在另一有利方法變更例’基本頻率fl的相位與信號走 勢的其他基本頻率f2，f3的相位藉著排除計算法同時測定。 如果假設基本頻率f2的頻率為基本頻率fl的兩倍，且 假設為基本頻f3的頻率為基本頻率fl的兩倍。則這種掃晦 方法的擴充可有利地使用。 田 如果藉著提高掃瞄頻率fs將基本頻率的泛音消除，則 可有利地將扭曲的正弦波信號走勢（它由數個基本頻率组 合）簡單地重建。 广有利的方法變更例，使用具有濾波功能的類比濾 波器以測定基本頻率的相位，該濾波器的最大通過係大致 在基本頻率的頻率。如此可另外提高相位測定作用的品質。 特別有利的係該掃瞄方法的應用，其係用於用聲波及 /或光學分析方法測量相位。 200914845 本發明在以下利用圖式中所示之實施例詳細說明。 【實施方式】 第1圖顯示在一正弦波形信號走勢（1)的掃瞄方法，一 如迄今習用者’其中顯示信號走勢⑴之隨時間變化的振幅 (20)與時間（10)的關係。在此實施例中顯示未扭曲的正弦波 信號，其沿其週期的信號走勢（1)利用等距離的掃瞄在一掃 # 瞄頻率fs檢出，此掃瞄頻率相當於所要測的基本頻率fl(3 υ 的四七頻率，其中對於各掃瞄點測定一掃瞄值s 1 (1 〇 1)、 S2(l〇2)、S3(l〇3)及S4(l〇4)，且信號走勢（1)的相位0可利用 以下關係測定： /?細印=arctan / 、 U-&J (2) 反之，圖2則顯示一扭曲的信號走勢（1)，其基本頻率 6(31)藉著一第一和諧泛波（32)(具頻率2xfi)及一第二和 ί 咱的泛波（33)(具頻率3x6 )扭曲。固然在分析後可用圖示 之取樣模式排除具頻率2x6的第一泛波2)，但不能排除具 頻率3xfi的第二泛波（33)。 圖3顯示在一頻率座標圖中的性質，該圖中利用傅立 葉（Fourier)分析測定。在此分析中顯示含在信號走勢 中各不同頻率（30)的振幅（2〇)。在細節上係基本頻率fl(31) 第泛波（32)及第一泛波（3 3)，其波幅相對基本頻率fi(3 i ) 減少，其頻率相當於基本頻率fi的二倍或三倍。在圖示實 ^例，掃瞄頻率fs對應於所要測量之基本頻率f〗（3 1)的四倍 200914845 頻率之圖1中的掃瞄點。對應地，在圖示例子中奈奎斯特 (Nyquist )極限頻率fN4 1 (= 一半之掃瞄頻率fs )等於第 一泛波（32)的頻率2xfl ’後者可分係以作排除。對應於此 Nyquist-Shannon掃瞄理論，此具有頻率3><fi的第二泛波不 再能明確地檢出。 圖4中顯示相同之扭曲的正弦波信號走勢（1),其中該 掃瞄方法依本發明利用一掃瞄頻率fs(4〇)實施，使得該奈奎 斯特極限頻率fN(4 1)〔它相當於一半之掃瞄頻率6(4〇)〕至 少相當於最高的所要排除的泛波（33)的兩倍頻率。在圖示的 例子中，掃瞄頻率fs(4〇)比所要測量的基本頻率fi(31)高十 二倍。在此，奈奎斯特極限頻率fN(41)為所要排除的泛波（33) 的頻率的兩倍。在掃瞄頻率fs(4〇)的合，沿著信號走勢 的一週期的掃瞄的數目選設成使該數目小於在掃瞄頻率 fs(40)的場合理論上可能的掃瞄點的數目。在圖示之例子只 有八個掃瞄點，其中測定掃瞄值s〇 (週期開始）（1〇〇)、 S2(l〇2) 、 S3(l〇3) 、 S4(l〇4) 、 S5(l〇5) 、 S6(106)及 S8(108)、 S9(l〇9)及Su(lll)，沿著信號走勢（1)的週期的二個掃瞄點 之間的時間間隔係各不同者，其中二個先後相隨的掃瞄點 的最小時間間隔由隔瞄頻率fs(4〇)預設。 圖5顯示在一頻率座標圖中依圖4所示的掃瞄的性質。 #號走勢（1)的相位Φ可在泛波（32)(33)排除後利用下 式測定： (3) 相位 p = 了+arctan 200914845 用圖示的取樣模式，複雜性的增加只有4個附加的加 法，因此該計算可簡單铋A 他占 間早地在一微處理機中實施。和此相較， 利用-數位滤波器將不要的頻率排除的做法較複雜。 圖6中顯示掃瞄方法的-方法變更例。沿信號走勢⑴ 的週期掃瞒後’將掃瞒點利用一掃瞒移動作業⑼)移動各 -段最小時間間隔〔它利用掃猫頻率fs⑽測定〕，並測定 此信號走勢⑴的新週期内的新的掃瞒值（ι〇〇)〇12)。和 圖4的方式〔用掃瞒值s〇 (週期開始）（1〇〇)、^(1〇2)、 S3(l〇3)、S5(1G5)、S6(1G6)、S8(1G8)、s9(l〇9)及 Swill)作 第人掃〕不同，在第一次掃猫移動作業⑼後，測定掃 ⑴〇)及Sl2⑴2)。對各新掃瞄、相位敎可用下式測 L+- -2πΧ (4) ί 其中X表示掃瞄移動作業（50)的次數。 利用此方法’可將掃猫移動作業對應於在掃聪頻率 =〇)的場合在信號走勢⑴一週期内可能的掃晦點的數目 5设，則由各測定的相位值計算相位平均值， 相位^相位 ίΚΟ nAVG W ) 同時排除計 其中nAVG為相位平均值的相位測定數數目 在另一方法實施例中’該掃瞄方法可就「 200914845 算方式」以測定基本頻_ fl(31)的相位以及信號走勢⑴的 其他基本頻率fs(34)、f3(37)的相位的方面擴充。在此實例 中，假設一頻為基本頻率f2(34)，比頻率為基本頻率 的兩倍大，並假設一頻率為基本頻率6(37)，它為基本頻率 fi(31)的三倍。 藉著將信號走勢（1)的基本頻率6(34)、5(37)排除以計 算基本頻率fl(31)的作業係利用以下方程式，其中所用之掃 瞄頻率fs(40)為一比最低基本頻率£1(31)大24倍的頻率： 相如(以) arctan (^18+X +i^22+x)~(^6+X _ (S〇+x + ) - (5\2+x + 5\6+x ) 0+X> (6) 利用排除信號走勢（1)的基本頻率fi(31)、f3(37)計算基 本頻率f2(34)的作業係利用以下方程式計算 相位〆/2，；〇=2 + 二^_ 24 •f arctan (S9+x +^2ΐ4χ)~(^3+Χ +S\5+Xj (*^〇+Χ + *^12+χ) — (^6+Χ + *^18+Χ> ⑺ 利用排除信號走勢f1(31)、f2(34)計算基本頻率f2(34) 的作業係利用以下方程式計算： 相位 9>(/3,X)= η -2τύί ^ ：--H arctan 24 >6+Χ + 夕u+x + S22+ x)~(S:V [Prior Art] For example, such a scanning method is used for information technology or for interferometer measurement purposes. The so-called Nyquist_Shann〇n scan theory or WKs sample. Booklet (for Whittaker-Kotelnikow-Shannon). The basic principles of technology, signal processing and information theory, scanning theory mentioned: - a continuous, (four) limited signal [minimum frequency 〇, maximum frequency fmax] shell with a frequency sweep greater than 2xfmax, 俾 energy The time thus obtained is not: the signal reconstructs the original signal without loss of information, but with an infinitely large number, or with an arbitrary accurate approach with P艮 cost. In the general case, the following equation (1) is applied to the perceptual frequency (sampling frequency) fs: 0) fS > 2 (fmax - fmin) (for w > 〇 )) In fact, the scanning theory indicates: Frequency, for example, will be a = in the knowledge, you must know or find the 辇 妍 H ^ °, use the frequency sweep signal to use the pass-through industry for analysis, and if we I g && For a good approach, the signal must be used more than the double-twisted frequency to double the frequency (four) (the purpose of 200914845). The limit frequency of the signal to be scanned (it can use the broom) The frequency is reconstructed without error) called the Nyquist frequency fN, and is equivalent to half the broom frequency ff. In practice, there is often a purpose: to distort (distort) the harmonic wave (Oberschwingung, English: overtone) (Verzerren ' The sinusoidal waveform signal of the English: Distortion is decomposed using a digital calculation method. Therefore, the object of the present invention is to provide a fast scanning method which can maintain high precision on the one hand, but can also be simply used in today's computer systems. Implementation (impleme [Abstract] This object is achieved by: the phase of at least one fundamental frequency of the signal trend and the phase of the flood wave are excluded by simultaneous detection of the lower or upper flood wave and simultaneously measured. The advantage is that the calculation is limited to simply obtaining the difference or quotient, and the method can be implemented simply and inexpensively in today's computer. Therefore, the phase of such a distorted signal can be determined quickly and simply. A particularly advantageous method variant is The (iv) frequency Μ is implemented at a frequency such that a phase of Nyquist C Myquist at a frequency of - 89 'half scan limits the frequency f 丨 ^ ^ relative to the maximum flooding of the two waves to be excluded In the example, at the scanning frequency fs, the number of sweeping frequencies f砗@U is selected in the period of β = Hai t唬, which is smaller than the possible scanning points on the zero volume of the sweep. The number of ig ΛΑ _ ^ ^ , , and the interval between the temples of a knowledgeable field point of -k / month along the signal trend, the minimum time interval between the two first species of 200914845 followed by the broom point Preset by broom frequency & The calculation steps to be implemented are reduced to a minimum. If the cat is swept along the -cycle of the signal, the sweeping point will be used—(4) The cat moves the job to move the segment minimum interval, _ is determined by the broom frequency fs, and the signal is measured The new sweep 14 phase measurement in the new cycle of the trend can be implemented in different sweeps (4). These sweeps are beneficial to the larger cumbersome (Redundanz) and improve the accuracy. If here, the scan move operation corresponds to the sweep. When aiming frequency _ fs, the number of possible broom points in the one-week period of the signal trend is repeated 'and the phase value is calculated from the measured phase value', so that the statistical error is reduced in the phase measurement. In another advantageous method change, the phase of the fundamental frequency fl and the phase of the other fundamental frequencies f2, f3 of the signal potential are simultaneously measured by the exclusion calculation method. If it is assumed that the frequency of the fundamental frequency f2 is twice the fundamental frequency fl, and the frequency of the fundamental frequency f3 is assumed to be twice the fundamental frequency fl. An extension of this broom method can then be advantageously used. If the overtone of the fundamental frequency is eliminated by increasing the scanning frequency fs, it is advantageously possible to simply reconstruct the distorted sine wave signal (which is composed of several basic frequency combinations). In a widely advantageous method variant, an analog filter with a filtering function is used to determine the phase of the fundamental frequency, the maximum pass of which is approximately at the frequency of the fundamental frequency. This can additionally improve the quality of the phase measuring action. Particularly advantageous is the application of the scanning method for measuring phase with acoustic and/or optical analysis methods. 200914845 The invention is described in detail below using the embodiments shown in the drawings. [Embodiment] Fig. 1 shows a scanning method of a sinusoidal waveform signal trend (1), as in the prior art, in which the amplitude (20) of the signal trend (1) changes with time (10). In this embodiment, an undistorted sine wave signal is displayed, and its signal trend along its period (1) is detected by an equal distance scan at a sweep frequency fs, which is equivalent to the fundamental frequency fl to be measured. (3 四 of the four seven frequency, in which a scan value s 1 (1 〇 1), S2 (l 〇 2), S3 (l 〇 3) and S4 (l 〇 4) are measured for each scanning point, and the signal trend The phase 0 of (1) can be determined by the following relationship: /? fine print = arctan / , U- & J (2) Conversely, Figure 2 shows a distorted signal trend (1), its fundamental frequency 6 (31) Distorted by a first harmonic wave (32) (with frequency 2xfi) and a second and ί 泛 pan (33) (with frequency 3x6). Although the sampling mode can be used to exclude the frequency 2x6 after analysis. The first flood wave 2), but the second flood wave with frequency 3xfi (33) cannot be excluded. Figure 3 shows the properties in a frequency coordinate plot, which is determined using Fourier analysis. The amplitude (2〇) of the different frequencies (30) contained in the signal trend is shown in this analysis. In detail, the fundamental frequency fl(31) is the first wave (32) and the first wave (3 3), and its amplitude is reduced relative to the fundamental frequency fi(3 i ), and its frequency is equivalent to twice or three of the fundamental frequency fi. Times. In the example shown, the scan frequency fs corresponds to four times the fundamental frequency f (3 1) to be measured. The scan point in Figure 1 of the frequency of 200914845. Correspondingly, in the illustrated example, the Nyquist limit frequency fN4 1 (= half of the scan frequency fs) is equal to the frequency of the first flood (32) 2xfl 'the latter can be classified for exclusion. Corresponding to this Nyquist-Shannon scanning theory, this second flood with frequency 3 << fi can no longer be clearly detected. The same distorted sine wave signal trend (1) is shown in Figure 4, wherein the scanning method is implemented in accordance with the present invention using a scan frequency fs (4 〇) such that the Nyquist limit frequency fN(4 1) The equivalent of half the scan frequency of 6 (4 〇) is at least equivalent to twice the frequency of the highest unwanted wave (33). In the illustrated example, the scan frequency fs (4 〇) is twelve times higher than the fundamental frequency fi (31) to be measured. Here, the Nyquist limit frequency fN(41) is twice the frequency of the flood (33) to be excluded. At the scan frequency fs (4 〇), the number of scans along a period of the signal trend is selected such that the number is smaller than the theoretically possible number of scan points at the scan frequency fs (40). . In the example shown, there are only eight scanning points, in which the scanning values s〇 (cycle start) (1〇〇), S2(l〇2), S3(l〇3), S4(l〇4), S5(l〇5), S6(106) and S8(108), S9(l〇9) and Su(lll), the time interval between two scan points along the period of the signal trend (1) For each different person, the minimum time interval between two successive scanning points is preset by the shielding frequency fs (4〇). Figure 5 shows the nature of the scan shown in Figure 4 in a frequency coordinate plot. The phase Φ of the ## trend (1) can be determined by the following equation after the wave (32) (33) is excluded: (3) Phase p = +arctan 200914845 With the sampling mode shown, the complexity increases by only 4 Additional additions, so the calculation can be implemented simply in a microprocessor early. In contrast, the use of a digital filter to eliminate unwanted frequencies is more complicated. Fig. 6 shows a method of changing the method of the scanning method. After sweeping along the period of the signal trend (1), 'sweep the broom point with a broom move operation (9)) move the minimum time interval of each segment (which is measured by the sweeping cat frequency fs(10)), and measure the new cycle within the new cycle of this signal trend (1) The broom value (ι〇〇)〇12). And the method of Fig. 4 [Broom value s〇 (cycle start) (1〇〇), ^(1〇2), S3(l〇3), S5(1G5), S6(1G6), S8(1G8) S9 (l〇9) and Swill) are different. In the first scan of the cat (9), the sweep (1) 〇) and Sl2 (1) 2) are measured. For each new scan, phase 敎 can be measured by the following formula: L+- -2πΧ (4) ί where X is the number of times the scan moves (50). By using this method, the number of possible broom points in the signal trend (1) can be set 5 in the case where the sweeping mouse movement operation corresponds to the sweeping frequency = 〇, and the phase average value is calculated from the measured phase values. Phase ^phase ΚΟ nAVG W ) Simultaneously exclude the number of phase measurements in which nAVG is the phase average. In another method embodiment, the scan method can be used to determine the fundamental frequency _ fl(31). The phase and the phase of the other fundamental frequencies fs (34) and f3 (37) of the signal trend (1) are expanded. In this example, it is assumed that the primary frequency is the fundamental frequency f2 (34), which is twice the frequency of the fundamental frequency, and a frequency is assumed to be the fundamental frequency 6 (37) which is three times the fundamental frequency fi(31). By excluding the basic frequencies 6(34), 5(37) of the signal trend (1) to calculate the fundamental frequency fl(31), the following equation is used, wherein the scanning frequency fs(40) used is the lowest ratio. The frequency of the basic frequency £1 (31) is 24 times larger: like (in) arctan (^18+X +i^22+x)~(^6+X _ (S〇+x + ) - (5\2 +x + 5\6+x ) 0+X> (6) The operation system for calculating the fundamental frequency f2 (34) using the fundamental frequencies fi(31) and f3(37) of the excluded signal trend (1) uses the following equation to calculate the phase 〆/2,;〇=2 + two^_ 24 •f arctan (S9+x +^2ΐ4χ)~(^3+Χ +S\5+Xj (*^〇+Χ + *^12+χ) — (^6+Χ + *^18+Χ> (7) The operation system for calculating the fundamental frequency f2(34) using the excluded signal trends f1(31), f2(34) is calculated by the following equation: Phase 9>(/3,X) = η -2τύί ^ :--H arctan 24 >6+Χ + 夕u+x + S22+ x)~(S:
4. e 2+X ^°10+X + l^18+x) W + 58+X + 夕 16+X)- (A+X + \ 2+X + S. 20+X, ⑻ 藉著提高掃晦頻率fs(4〇)可排除基本頻率（3 1)(34)(37) 的泛波（32)(33)(35)(36)(37)(38)，這點可造成進一步改良。 圖7顯示基本頻率（3 1)(34)(37)及泛波 ㈠2)(33)(35)(36)(38)(39)的頻率座標圖。此外顯示Nyquist 限制頻率fN(4l)〔對應於一半之掃瞄頻率匕（4〇)〕。為了達 200914845 成將信號脈波⑴的扭曲充分排除。舉例而纟，係不同於最 低基本頻率而使用七十二倍的掃瞄頻率6(4〇)，這點特別是 當在將純正弦信號解除扭曲時特別有利。然在此，基本頻 率fi(31)要儘量對應使用，且基本頻率（31)的第一及第二和 諧泛波（32)(37)會影響基本頻率（34)(37)的值。 為了改善基本頻率（31)(34)(37)作相位測定的品質，故 使用具濾波功能（60)的類比濾波器，它有濾波功，這些濾波 功能的最高透過度係主要在限制頻率（3丨）（34)(37)的頻域 中。因此較高階的泛波可濾掉。對於濾波器的效率（以排 除較咼之和諧泛波）以及雜訊比及濾波器反應速度之間的 最佳妥協’在以改變的參數重新測量時，濾波功能（60)作對 應的選擇。 圖δ顯示一典型濾波功能（6〇)的示意圖，其中顯示通過 性（61)的對數值很頻率的對數值（1〇g f)(62)的關係。在此， 渡波功能（60)的最大值在基本頻率（31)(34)(37)的頻域中。 原理上’此掃瞄方法也可用在基本頻率（3 1 )(34)(37)的 場合’它們具有一種有理數比例，例如fi為^xfi及|xfi或 者例如f〗為|xfl及|xf 2 2 1 【圖式簡單說明】 第1圖係在一種正弦波形信號走勢依先前技術的掃瞄 方法的示意圖； 第2圖係用泛波扭曲的信號走勢的掃瞄方法； 第3圖係一頻率座標圖； 12 200914845 第4圖係依本發明的掃瞄方法的示意圖； 第5圖為另一頻率座標圖； 第6圖係該掃瞄方法的一變更例； 第7圖係具有濾波功能的一頻率座標圖； 第8圖係濾波功能用的通過特性線的示意圖。 【主要元件符號說明】 (1) 信號走勢 (10) 時間 (20) 振幅 (3 1)(34)(37) 共本頻率fi (32) 第一（和諧） 泛波 (33) 弟二（和Ί皆） 泛波 (35)(36)(38)(39) 泛波 (40) 掃瞄頻率fs (60) 濾波功能 (62) 頻率對數值log f (100) 掃瞒值S〇 (101) 掃瞒值S 1 (102) 掃猫值S 2 (103) 掃瞎值S 3 (104) 掃瞎值s4 (105) 掃晦值S 5 (106) 掃瞒值s6 13 200914845 (108) (109) (ill) 掃瞎值S 8 掃0¾值S 9 掃瞄值sn /' c 144. e 2+X ^°10+X + l^18+x) W + 58+X + 夕16+X)- (A+X + \ 2+X + S. 20+X, (8) by improving The broom frequency fs(4〇) excludes the flood (32)(33)(35)(36)(37)(38) of the fundamental frequency (3 1)(34)(37), which can lead to further improvements. Figure 7 shows the frequency coordinates of the fundamental frequencies (3 1) (34) (37) and the flood (1) 2) (33) (35) (36) (38) (39). In addition, the Nyquist limit frequency fN(4l) is displayed [corresponding to half of the scan frequency 匕(4〇)]. In order to reach 200914845, the distortion of the signal pulse (1) is fully excluded. For example, it is different from the lowest fundamental frequency and uses seventy-two times the scanning frequency of 6 (4 〇), which is particularly advantageous when the pure sinusoidal signal is untwisted. Here, the fundamental frequency fi(31) should be used as much as possible, and the first and second harmonic waves (32) (37) of the fundamental frequency (31) affect the value of the fundamental frequency (34) (37). In order to improve the quality of the phase measurement of the fundamental frequency (31)(34)(37), an analog filter with a filtering function (60) is used, which has filtering power, and the highest transmittance of these filtering functions is mainly at the limiting frequency ( 3丨) (34) (37) in the frequency domain. Therefore, higher order floods can be filtered out. The filter function (60) is chosen accordingly for the efficiency of the filter (to eliminate the more ambiguous harmonic wave) and the best compromise between the noise ratio and the filter response speed. Figure δ shows a schematic diagram of a typical filtering function (6〇) showing the logarithmic value (1〇g f) (62) of the logarithm of the passivity (61). Here, the maximum value of the wave function (60) is in the frequency domain of the fundamental frequency (31) (34) (37). In principle, this scanning method can also be used in the case of the fundamental frequency (3 1 )(34)(37). They have a rational ratio, for example, fi is ^xfi and |xfi or, for example, f is |xfl and |xf 2 2 1 [Simple description of the diagram] Figure 1 is a schematic diagram of a sinusoidal waveform signal according to the scanning method of the prior art; Figure 2 is a scanning method of the signal trend of the distortion of the flooded wave; Figure 12; Fig. 4 is a schematic diagram of a scanning method according to the present invention; Fig. 5 is another frequency coordinate diagram; Fig. 6 is a modification of the scanning method; and Fig. 7 is a filtering function A frequency coordinate map; Figure 8 is a schematic diagram of the pass characteristic line for the filtering function. [Explanation of main component symbols] (1) Signal trend (10) Time (20) Amplitude (3 1) (34) (37) Common frequency fi (32) First (harmonic) Flood (33) Brother II (and Ί all) Flood (35)(36)(38)(39) Flood (40) Scan frequency fs (60) Filter function (62) Frequency log value log f (100) Broom value S〇(101) Broom value S 1 (102) Sweeping cat value S 2 (103) Broom value S 3 (104) Broom value s4 (105) Broom value S 5 (106) Broom value s6 13 200914845 (108) (109 ) (ill) Broom value S 8 Sweep 03⁄4 value S 9 Scan value sn /' c 14