The principle of shielded cable:<\/p>\n
The shielded wiring system originated in Europe. It adds a metal shielding layer to the ordinary unshielded wiring system, and uses the reflection, absorption and skin effect of the metal shielding layer to prevent electromagnetic interference and electromagnetic radiation. The shielding system comprehensively utilizes the balance principle of twisted pair cables and the shielding effect of the shielding layer, and therefore has very good electromagnetic compatibility (EMC) characteristics.<\/p>\n
Electromagnetic compatibility (EMC) refers to the ability of electronic equipment or network systems to resist electromagnetic interference to a certain extent, while not generating excessive electromagnetic radiation. In other words, it requires that the equipment or network system can work normally in a relatively harsh electromagnetic environment, while not radiating too much electromagnetic waves to interfere with the normal operation of other surrounding devices and networks.<\/p>\n
The balance characteristics of U\/UTP (unshielded) cables do not only depend on the quality of the components themselves (such as twisted wires), but are also affected by the surrounding environment. The metal around the U\/UTP (unshielded), the hidden "ground wire", the pulling and bending during the construction process, etc. will destroy the balance characteristics, thereby reducing the EMC performance.<\/p>\n
Therefore, there was only one solution to obtain lasting balanced properties: ground all cores with an additional layer of aluminum foil. The aluminum foil adds protection to the fragile twisted pair cores and creates an artificial balanced environment for the U\/UTP (unshielded) cable. This creates what we now call shielded cable.<\/p>\n
The shielding principle of shielded cable is different from the balanced offset principle of twisted pair cable. Shielded cable is to add one or two layers of aluminum foil outside the four pairs of twisted pair cables, and use the reflection, absorption and skin effect principle of metal on electromagnetic waves (the so-called skin effect refers to the distribution of current on the conductor cross section tends to the conductor surface with the increase of frequency. The higher the frequency, the smaller the skin depth, that is, the higher the frequency, the weaker the penetration ability of electromagnetic waves). It effectively prevents external electromagnetic interference from entering the cable and prevents internal signals from radiating out and interfering with the work of other equipment.<\/p>\n
Experiments show that electromagnetic waves with frequencies above 5MHz can only pass through 38\u03bcm thick aluminum foil. If the thickness of the shielding layer is allowed to exceed 38\u03bcm, the electromagnetic interference frequency that can pass through the shielding layer and enter the cable will be mainly below 5MHz. Applying the balance principle of twisted pair cables can effectively offset low-frequency interference below 5MHz.<\/p>\n
According to the earliest definition of cabling, there are two types: unshielded cable \u2013 UTP and shielded cable \u2013 STP. Later, with the development of technology and different processes, many different shielding types have been derived. 1.b) S\/FTP (PIMF) Single pair of aluminum foil shielding plus copper wire braided outer four pairs of conductors PIMF = Pair in Metal Foil.<\/p>\n
Shielded cables are resistant to external interference, mainly because the shielding system ensures the integrity of signal transmission. Shielded wiring systems can prevent data transmission from external electromagnetic interference and radio frequency interference. Electromagnetic interference (EMI) mainly refers to low-frequency interference. Motors, fluorescent lights and power lines are common sources of electromagnetic interference. Radio frequency interference (RFI) is high-frequency interference, mainly radio frequency interference, including radio, TV transmissions, radar and other wireless communications.<\/p>\n
For resisting electromagnetic interference, it is most effective to choose braided layer shielding, that is, metal mesh shielding, because its critical resistance is very low. For radio frequency interference, metal foil layer shielding is most effective, because the gaps created by metal mesh shielding allow high-frequency signals to enter and exit freely. For interference fields with mixed high and low frequencies, a combination of metal foil layer and metal mesh shielding, that is, double-shielded cable in the form of S\/FTP, should be used, so that the metal mesh shielding can be used for interference in the low-frequency range, and the metal foil layer shielding can be used for interference in the high-frequency range.<\/p>\n
The single-layer thickness of the aluminum foil shielding layer in the IBM ACS shielded cable is 50-62\u03bcm, which can achieve a relatively complete shielding effect. At the same time, since only a single-layer shielding is used, it will be simpler for construction and easier to install. It is not easy to cause human damage during the construction process, and the thickness of the aluminum foil can withstand greater damage. Therefore, it can provide users with better transmission performance.<\/p>","protected":false},"excerpt":{"rendered":"
Definition of shielded wire: The wire wrapped outside the conductor is called shielded wire, and the wrapped conductor is called shielding layer, which is generally copper mesh or copper (aluminum) braided. The shielding layer needs to be grounded, and the external [\u2026]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"default","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[19],"tags":[253,236],"class_list":["post-5839","post","type-post","status-publish","format-standard","hentry","category-blog","tag-blog","tag-pingbixian"],"_links":{"self":[{"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/posts\/5839","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/comments?post=5839"}],"version-history":[{"count":0,"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/posts\/5839\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/media?parent=5839"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/categories?post=5839"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ray-tron.com\/en\/wp-json\/wp\/v2\/tags?post=5839"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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