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Introdución de varios cables usados ​​en vixilancia e seguridade

2021-02-04

Introdución de varios cables comúns usado enVixilanciae seguridade

The most widely used cables in surveillance e seguridade projects include coaxial cables, twisted pairs, eoptical fibers. The following are the main points of knowledge about the usage methods and functions of these commonly used cables, así como as diferenzas entre eles.

 

1. Cable coaxial

 

 

Cable coaxial is a cable with a central copper conductor wrapped in layers of insulated wires. It is characterized by good anti-interference ability, stable data transmission, elow price. It is also widely used, such as closed-circuit television lines. Coaxial thin cables are generally sold at a few yuan per meter in the market, which is not too expensive. Cable coaxials are used to connect with BNC connectors. The coaxial cables sold on the market are generally finished products that have been connected with BNC connectors.

 

Na práctica de enxeñaría, para ampliar a distancia de transmisión, úsase un amplificador coaxial. O amplificador coaxial pode amplificar o sinal de vídeo ata certo punto e tamén pode compensar diferentes compoñentes de frecuencia en diferentes tamaños mediante axuste de igualación, para minimizar a distorsión da saída de sinal de vídeo polo extremo receptor. Non obstante, os amplificadores coaxiais non poden ser en cascada indefinidamente. Xeralmente, só de 2 a 3 amplificadores coaxiais poden ser en cascada nun sistema punto a punto. Se non, a calidade da transmisión de vídeo non se pode garantir e o axuste é difícil. Polo tanto, cando se usan cables coaxiais nun sistema de monitorización, para garantir unha mellor calidade de imaxe, o rango de distancia de transmisión limítase xeralmente a uns 400-500 metros.

Ademais, os cables coaxiais aínda presentan algunhas deficiencias na transmisión de sinais de imaxe no sistema de monitorización:

1) O cable coaxial en si é moi afectado polo cambio climático e a calidade da imaxe vese afectada ata certo punto;

2) O cable coaxial é relativamente groso, o que non é conveniente para o cableado en aplicacións de monitorización densas;

3) Cable coaxials generally can only transmit video signals. If the system needs to transmit control data, audio and other signals at the same time, additional wiring is required;

4) Cable coaxial has limited anti-interference ability and cannot be usado enstrong interference environment;

5) O amplificador coaxial tamén ten a desvantaxe da dificultade de axuste.

 

2.Cable Ethernet Cable torcido

 

Os cables comúns de par trenzado sonCAT5eCAT5E, CAT6, eCAT7. O primeiro ten un diámetro de arame fino e o segundo ten un diámetro de arame groso. Os modelos son os seguintes:

 

5) CAT5 cable: This type of cable has increased winding density, a high-quality insulation material, ea transmission rate of 100MHz. It is used for voice transmission and data transmission with a maximum transmission rate of 100Mbps. It is mainly used for 100BASE-T and 10BASE-T network. This is the most commonly used Ethernet cables.

6) CAT5 cable: CAT5 has low attenuation, less crosstalk, higher attenuation to crosstalk ratio (ACR), signal-to-noise ratio (Structural Return Loss), smaller delay error, eperformance Greatly improved. The maximum transmission rate of CAT5E cable is 250Mbps.

7) Cable CAT6: a frecuencia de transmisión deste tipo de cable é de 1 MHz250MHz, ethe comprehensive attenuation crosstalk ratio (PS-ACR) of Category 6 wiring system should have a larger margin at 200MHz. It provides two times the power of CAT5 bandwidth. The transmission performance of Category 6 cabling is much higher than that of the Super Category 5 standard, eis most suitable for applications with a transmission rate higher than 1Gbps.

 

An important difference between CAT6 and CAT5 is: improved crosstalk and return loss performance. For a new generation of full-duplex high-speed network applications, excellent return loss performance is extremely important. The basic link model is canceled in the six types of standards, ethe wiring standard adopts a star-shaped topology. The required wiring distance is: the length of the permanent link cannot exceed 90m, ethe channel length cannot exceed 100m.

8)CAT6A Cable: CAT6A Cable is an improved version of Category 6, which is also an unshielded twisted pair cable specified in ANSI/EIA/TIA-568B.2 and ISO Category 6/Class E standards. Mainly usado engigabit networks. In terms of transmission frequency, it is also 200-250 MHz like Category 6 lines, ethe maximum transmission speed can also reach 1 000 Mbps, but it is greatly improved in terms of crosstalk, attenuation and signal-to-noise ratio.

9) Cable CAT7: esta liña é o último par trenzado da norma ISO 7 / F. Úsase principalmente para adaptarse á aplicación e desenvolvemento da tecnoloxía Ethernet de 10 Gigabit. Pero xa non é un par trenzado sen apantallar, senón un par trenzado protexido, polo que a súa frecuencia de transmisión pode alcanzar polo menos 500 MHz, o que supera o dobre que os cables CAT 6 e CAT6A. Ata 10 Gbps.

 

 

3. Fibra óptica

Fibra óptica (Fiber Optic Cable) transmits signals in the form of light pulses, so the material is mainly glass or plexiglass. It consists of a fiber core, a cladding and a protective cover.

 

The structure of the optical fiber is very similar to that of a coaxial cable, ethe center is an optical fiber made of glass or transparent plastic, surrounded by a protective material, emultiple optical fibers can be combined in one optical cable as needed. According to different optical signal generation methods, optical fibers can be divided into single-mode fibers and multi-mode fibers. To

 

Multimode fiber is generally used for network connections in the same office building or in a relatively close area. The single-mode optical fiber transmits data with higher quality and longer transmission distance, eis usually used to connect office buildings or geographically dispersed networks. If optical fiber and cable are used as the network transmission medium, it is necessary to add equipment such as optical transceivers, so the cost investment is greater and it is less usado engeneral applications.

 

The biggest feature of optical fiber is that it conducts optical signals, so it is not interfered by external electromagnetic signals, ethe signal attenuation speed is very slow, so the signal transmission distance is much longer than the above various network cables that transmit electrical signals, eit is especially suitable for Places with harsh electromagnetic environment.

 

Debido ás características de reflexión óptica da fibra óptica, pódense transmitir múltiples sinais ao mesmo tempo dentro dunha fibra óptica, polo que a velocidade de transmisión da fibra óptica pode ser moi alta. Actualmente, a rede de fibra óptica de 1 Gbps 1000 Mbps converteuse na rede de alta velocidade principal. Teoricamente, a rede de fibra óptica pode alcanzar ata 50000Gbps a 50Tbps. velocidade.