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傳輸線中電長(zhǎng)度（electrical length）的意義 |
| 作者：tg.liu 欄目：通信技術(shù) |
請(qǐng)教各位電長(zhǎng)度（electrical length）是如何定義的 |
| 2樓： | >>參與討論 |
| 作者： feng_zc 于 2005/7/23 15:50:00 發(fā)布：
傳輸線的長(zhǎng)度與傳輸波長(zhǎng)（在傳輸線中）的比值 |
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| 3樓： | >>參與討論 |
| 作者： tg.liu 于 2005/7/23 18:32:00 發(fā)布：
那么當(dāng)波長(zhǎng)和物理長(zhǎng)度確定時(shí)，電長(zhǎng)度是否就是固定值了？ |
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| 4樓： | >>參與討論 |
| 作者： tg.liu 于 2005/7/23 18:36:00 發(fā)布：
還是不明白（有一份英文解釋?zhuān)?br>在網(wǎng)上搜到一份英文解釋?zhuān)皇呛苊靼住?br>請(qǐng)?jiān)�，本人初次涉及RF electrical length -------------------------------------------------------------------------------- electrical length: 1. Of a transmission medium, its length expressed as a multiple or submultiple of the wavelength of a periodic electromagnetic or electrical signal propagating within the medium. Note 1: The wavelength may be expressed in radians or in artificial UNITS of angular measure, such as degrees. Note 2 : In both coaxial CABLES and OPTICAL fibers, the velocity of propagation is approximately two-thirds that of free space. Consequently, the wavelength will be approximately two-thirds that in free space, and the electrical length, approximately 1.5 times the physical length. 2. Of a transmission medium, its physical length multiplied by the ratio of (a) the propagation time of an electrical or electromagnetic signal through the medium to (b) the propagation time of an electromagnetic wave in free space over a distance equal to the physical length of the medium in question. Note: The electrical length of a physical medium will always be greater than its physical length. For example, in coaxial CABLES, distributed resistances, capacitances and inductances impede the propagation of the signal. In an OPTICAL fiber, interaction of the lightwave with the materials of which the fiber is made, and fiber geometry, affect the velocity of propagation of the signal. 3. Of an antenna, the effective length of an element, usually expressed in wavelengths. Note 1: The electrical length is in general different from the physical length. Note 2: By the addition of an appropriate reactive element (capacitive or inductive), the electrical length may be made significantly shorter or longer than the physical length. |
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| 5樓： | >>參與討論 |
| 作者： computer00 于 2005/7/23 18:48:00 發(fā)布：
電長(zhǎng)度就是指在工作條件下表現(xiàn)出來(lái)的電氣長(zhǎng)度，對(duì)應(yīng)的有物理長(zhǎng)度 物理長(zhǎng)度就是實(shí)際用尺測(cè)量出來(lái)的長(zhǎng)度。 電長(zhǎng)度主要跟介質(zhì)參數(shù)有關(guān)。 |
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| 6樓： | >>參與討論 |
| 作者： computer00 于 2005/7/23 19:57:00 發(fā)布：
試著翻譯了一下： electrical length -------------------------------------------------------------------------------- electrical length: 1. Of a transmission medium, its length expressed as a multiple or submultiple of the wavelength of a periodic electromagnetic or electrical signal propagating within the medium. Note 1: The wavelength may be expressed in radians or in artificial UNITS of angular measure, such as degrees. Note 2 : In both coaxial CABLES and OPTICAL fibers, the velocity of propagation is approximately two-thirds that of free space. Consequently, the wavelength will be approximately two-thirds that in free space, and the electrical length, approximately 1.5 times the physical length. 2. Of a transmission medium, its physical length multiplied by the ratio of (a) the propagation time of an electrical or electromagnetic signal through the medium to (b) the propagation time of an electromagnetic wave in free space over a distance equal to the physical length of the medium in question. Note: The electrical length of a physical medium will always be greater than its physical length. For example, in coaxial CABLES, distributed resistances, capacitances and inductances impede the propagation of the signal. In an OPTICAL fiber, interaction of the lightwave with the materials of which the fiber is made, and fiber geometry, affect the velocity of propagation of the signal. 3. Of an antenna, the effective length of an element, usually expressed in wavelengths. Note 1: The electrical length is in general different from the physical length. Note 2: By the addition of an appropriate reactive element (capacitive or inductive), the electrical length may be made significantly shorter or longer than the physical length. 電長(zhǎng)度 電長(zhǎng)度： 1.對(duì)于傳輸媒介，它的長(zhǎng)度被表示為一個(gè)在媒介中傳波的電或者電磁信號(hào)波長(zhǎng)的倍數(shù)。 注釋 1：波長(zhǎng)可能用弧度來(lái)表示，或者其它的角度單位來(lái)表示，如角度。 注釋 2：在同軸電纜和光纖中，傳輸速率大約為自由空間中的2/3。因此，波長(zhǎng) 大約為自由空間中波長(zhǎng)的2/3，而電長(zhǎng)度則大約為物理長(zhǎng)度的1.5 倍。 2.對(duì)于傳輸媒介，（電長(zhǎng)度）用 它的物理長(zhǎng)乘以 電或電磁信號(hào)在媒介中的傳輸 時(shí)間（時(shí)間為a）與 這信號(hào)在自由空間中通過(guò)跟媒介物理長(zhǎng)度一樣的距離時(shí)所 需的時(shí)間（時(shí)間為b）的比（即電長(zhǎng)度=物理長(zhǎng)度*a/b） 來(lái)考慮。 注釋?zhuān)簩?duì)于一個(gè)物理媒介來(lái)說(shuō)，它的電長(zhǎng)度總是大于它的物理長(zhǎng)度。例如，在同 軸電纜中，分布電阻、電容、電感阻礙了信號(hào)的傳輸；在光纖中，光波與 光纖材料之間的相互作用，以及光纖的幾何結(jié)構(gòu)，影響了信號(hào)的傳輸速率。 3.對(duì)于天線，天線的有效長(zhǎng)度常表示為波長(zhǎng)的倍數(shù)。 注釋 1.電長(zhǎng)度跟物理長(zhǎng)度通常是不一樣的。 注釋 2.通過(guò)增加一個(gè)適當(dāng)?shù)碾娍乖娙莼螂姼校�，電長(zhǎng)度可以顯著的短于或者長(zhǎng)于物理長(zhǎng)度。 |
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| 7樓： | >>參與討論 |
| 作者： tg.liu 于 2005/7/23 21:00:00 發(fā)布：
謝謝computer00的精解 回去慢慢領(lǐng)悟 |
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| 8樓： | >>參與討論 |
| 作者： iQanalog 于 2005/7/24 17:56:00 發(fā)布：
有益! |
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| 9樓： | >>參與討論 |
| 作者： baby 于 2008/12/3 16:29:03 發(fā)布：
電長(zhǎng)度定義：傳輸線的物理長(zhǎng)度與傳輸波長(zhǎng)（在傳輸線中）的比值 電長(zhǎng)度物理意義：舉個(gè)例子吧：物理長(zhǎng)度為1m的傳輸線，對(duì)于波長(zhǎng)分別為10cm和1cm的兩個(gè)電磁波，電長(zhǎng)度分別為10和100，也就是說(shuō)：在一米的傳輸線上波長(zhǎng)為10cm的波變化了10個(gè)周期，而波長(zhǎng)為1cm的波變化了100個(gè)周期�？梢�(jiàn)：相同物理長(zhǎng)度上波變化越頻繁電長(zhǎng)度越大！即電長(zhǎng)度是用來(lái)描述電磁波波形變化頻繁程度的物理量
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| 10樓： | >>參與討論 |
| 作者： sunfire 于 2008/12/25 17:16:14 發(fā)布：
從網(wǎng)上看到，以下內(nèi)容<對(duì)于傳輸媒介，（電長(zhǎng)度）用 它的物理長(zhǎng)乘以 電或電磁信號(hào)在媒介中的傳輸時(shí)間（時(shí)間為a）與 這信號(hào)在自由空間中通過(guò)跟媒介物理長(zhǎng)度一樣的距離時(shí)所需的時(shí)間（時(shí)間為b）的比（即電長(zhǎng)度=物理長(zhǎng)度*a/b） 來(lái)考慮>,所以可否得出結(jié)論,物理長(zhǎng)度/電長(zhǎng)度=傳輸速率? |
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