ព័ត៌មានឧស្សាហកម្ម

សេចក្តីផ្តើមនៃខ្សែមួយចំនួនដែលត្រូវបានប្រើជាទូទៅក្នុងការឃ្លាំមើលនិងសុវត្ថិភាព

2021-02-04

សេចក្តីផ្តើមនៃខ្សែមួយចំនួនជាទូទៅ ប្រើក្នុងការឃ្លាំមើលនិងសន្តិសុខ

The most widely used ខ្សែ in surveillance និងសន្តិសុខ projects include coaxial ខ្សែ, twisted pairsនិងoptical fibers. The following are the main points of knowledge about the usage methods and functions of these commonly used ខ្សែក៏ដូចជាភាពខុសគ្នារវាងពួកគេ។

 

1. ខ្សែ coaxial

 

 

ខ្សែ 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 transmissionនិងlow price. It is also widely used, such as closed-circuit television lines. Coaxial thin ខ្សែ are generally sold at a few yuan per meter in the market, which is not too expensive. Coaxial ខ្សែ are used to connect with BNC connectors. The coaxial ខ្សែ sold on the market are generally finished products that have been connected with BNC connectors.

 

In engineering practice, in order to extend the transmission distance, a coaxial amplifier is used. The coaxial amplifier can amplify the video signal to a certain extentនិងcan also compensate different frequency components in different sizes through equalization adjustment, so as to minimize the distortion of the video signal output by the receiving end. However, coaxial amplifiers cannot be cascaded indefinitely. Generally, only 2 to 3 coaxial amplifiers can be cascaded in a point-to-point system. Otherwise, the video transmission quality cannot be guaranteed and adjustment is difficult. Therefore, when using coaxial ខ្សែ in a monitoring system, in order to ensure a better image quality, the transmission distance range is generally limited to about 400-500 meters.

In addition, coaxial ខ្សែ still have some shortcomings in the transmission of image signals in the monitoring system:

1) ខ្សែកាបដោយខ្លួនវាត្រូវបានរងផលប៉ះពាល់យ៉ាងខ្លាំងពីការប្រែប្រួលអាកាសធាតុហើយគុណភាពរូបភាពត្រូវបានប៉ះពាល់ដល់កម្រិតជាក់លាក់មួយ។

2) ខ្សែ coaxial គឺក្រាស់ដែលមិនងាយស្រួលសម្រាប់ខ្សែនៅក្នុងកម្មវិធីត្រួតពិនិត្យក្រាស់;

3) Coaxial ខ្សែ 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) ខ្សែ coaxial has limited anti-interference ability and cannot be ប្រើក្នុងstrong interference environment;

5) អំព្លីអេឡិចត្រូនិចក៏មានគុណវិបត្តិនៃការលំបាកក្នុងការកែសំរួល។

 

២ ។ខ្សែអ៊ីសឺរណិត ខ្សែ twisted

 

Common twisted-pair ខ្សែ are Cអេធី ៥និងCអេធី ៥E, Cអេ6និងCអេ7។ អតីតមានអង្កត់ផ្ចិតលួសស្តើងនិងក្រោយមានអង្កត់ផ្ចិតលួសក្រាស់។ ម៉ូដែលមានដូចខាងក្រោម៖

 

5) Cអេធី ៥ cable: This type of cable has increased winding density, a high-quality insulation materialនិងa 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 ខ្សែ.

6) Cអេធី ៥ cable: Cអេធី ៥ has low attenuation, less crosstalk, higher attenuation to crosstalk ratio (ACR), signal-to-noise ratio (Structural Return Loss), smaller delay errorនិងperformance Greatly improved. The maximum transmission rate of Cអេធី ៥E cable is 250Mbps.

7) Cអេ6 cable: The transmission frequency of this type of cable is 1MHz250MHzនិងthe 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 Cអេធី ៥ bandwidth. The transmission performance of Category 6 cabling is much higher than that of the Super Category 5 standardនិងis most suitable for applications with a transmission rate higher than 1Gbps.

 

An important difference between Cអេ6 and Cអេធី ៥ 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 standardsនិងthe wiring standard adopts a star-shaped topology. The required wiring distance is: the length of the permanent link cannot exceed 90mនិងthe channel length cannot exceed 100m.

8)Cអេ6A Cable: Cអេ6A 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 ប្រើក្នុងgigabit networks. In terms of transmission frequency, it is also 200-250 MHz like Category 6 linesនិងthe 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) Cអេ7 Cable: This line is the latest twisted pair in the ISO 7/F standard. It is mainly used to adapt to the application and development of 10 Gigabit Ethernet technology. But it is no longer an unshielded twisted pair, but a shielded twisted pair, so its transmission frequency can reach at least 500 MHz, which is more than twice that of Cអេ 6 and Cអេ6A ខ្សែ. Up to 10 Gbps.

 

 

3. សរសៃ​អុបទិក

សរសៃ​អុបទិក (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 cableនិងthe center is an optical fiber made of glass or transparent plastic, surrounded by a protective materialនិងmultiple 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 distanceនិងis 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 ប្រើក្នុងgeneral applications.

 

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

 

ដោយសារតែលក្ខណៈឆ្លុះបញ្ចាំងអុបទិកនៃសរសៃអុបទិកសញ្ញាជាច្រើនអាចត្រូវបានបញ្ជូនក្នុងពេលតែមួយនៅខាងក្នុងអុបទិកដូច្នេះល្បឿនបញ្ជូននៃសរសៃអុបទិកអាចខ្ពស់ណាស់។ នាពេលបច្ចុប្បន្នបណ្តាញខ្សែកាបអុបទិក 1Gbps 1000Mbps បានក្លាយជាបណ្តាញល្បឿនលឿនចម្បង។ តាមទ្រឹស្តីបណ្តាញខ្សែកាបអុបទិកអាចឡើងដល់ 50000Gbps 50Tbps ។ ល្បឿន។