Hello, welcome to Zhuhai Hanqin Cable Co.,Ltd.   In this article, we will talk about the difference between coaxial cable and twist pair network cables.

First, COAXIAL CABLE:
Coaxial cable has the advantages of being cheaper and easier to lay
(Relative to optical fiber), so, generally in a small-scale monitoring system, by
Because the transmission distance is very short, the use of coaxial cables to directly transmit the monitoring image does not cause much damage to the image quality, which can meet the actual requirements.
However, according to the analysis of the characteristics of the coaxial cable itself, when the signal is transmitted in the coaxial cable, its attenuation is related to the transmission distance and the signal itself.
The frequency is related. Generally speaking, the higher the signal frequency, the greater the attenuation. The bandwidth of the video signal is very large, reaching
6MHz, and the color part of the image is modulated at the high end of the frequency. In this way, when the video signal is transmitted in the coaxial cable, not only the overall signal amplitude is attenuated, but also the attenuation of each frequency component varies greatly, especially the color part attenuation is the largest. Therefore, coaxial cables are only suitable for short-distance transmission of image signals. When the transmission distance reaches about 200 m, the image quality will be significantly reduced, especially the color becomes dim and there is a sense of distortion.

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 extent, and also
Different frequency components can be compensated in different sizes through equalization adjustment, so that the distortion of the video signal output by the receiving end is as small as possible. But
Yes, coaxial amplifiers cannot be cascaded indefinitely. Generally, coaxial amplifiers can only be cascaded up to 2  to 3  in a point-to-point system.
Otherwise, the video transmission quality cannot be guaranteed, and it is difficult to adjust. Therefore, when using a coaxial cable in a monitoring system, in order to ensure a better
Generally, the transmission distance is limited to about four or five hundred meters.
In addition, coaxial cables still have some shortcomings in the transmission of image signals in the monitoring system:
1) The coaxial cable itself is greatly affected by climate change, and the image quality is affected to a certain extent;
2) The coaxial cable is relatively thick, which is not convenient for wiring in intensive monitoring applications;
3) Generally, coaxial cables 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.
Line
4) Coaxial cable has limited anti-interference ability and cannot be used in strong interference environment;
5) The coaxial amplifier also has the disadvantage of difficulty in adjustment.

Second, Twisted pair
Twisted pair has been used for a long time. Telephone transmission uses twisted pair, which is used in many industrial control systems and places with greater interference and long distances.
Twisted-pair cables are used in remote transmission, and the local area network that we widely use today also uses twisted-pair cables. The reason why twisted pair is so widely used,
It is because it has many advantages such as strong anti-interference ability, long transmission distance, easy wiring, and low price. Since the twisted pair signal also exists
Larger attenuation, so when the transmission distance is long, the frequency of the signal cannot be too high, while high-speed signals such as Ethernet can only be restricted to
Within 100m. For video signals, the bandwidth reaches 6MHz. If it is directly transmitted in a twisted pair cable, it will also attenuate greatly. Therefore, the video signal is
To achieve long-distance transmission on a twisted wire, amplification and compensation must be carried out. The twisted pair video transmission equipment is to complete this function. Plus a pair of twisted pairs
After the line video transceiver equipment, the image can be transmitted from 1  to 2km. Twisted-pair and twisted-pair video transmission equipment are very cheap, not only without
Increasing the cost of the system, on the contrary, when the distance increases, its cost is much lower than that of the coaxial cable. Therefore, in the monitoring system, the twisted pair is used for transmission.
Transmission has obvious advantages: 1) Long transmission distance and high transmission quality. Due to the advanced processing technology used in the twisted pair transceiver, it perfectly compensates for the attenuation of the twisted pair to the video signal amplitude and the attenuation difference between different frequencies, and maintains the brightness and color of the original image and the real-time performance. When the transmission distance reaches 1km or more, the image signal is basically without distortion. If the relay mode is adopted, the transmission distance will be longer.
2) Convenient wiring and high cable utilization. A pair of ordinary telephone lines can be used to transmit video signals. In addition, the extensively paved buildings in the building
Any pair of unshielded twisted pair cables of category 5  can transmit one video signal without additional wiring. Even if it is re-wiring, category 5 cables are better than the same
Shaft cable is easy. In addition, a category 5 cable has 4 pairs of twisted-pair wires. If a pair of wires is used to transmit the video signal, the other pairs of wires can also be used.
To transmit audio signals, control signals, power supply or other signals, improve cable utilization, and avoid separate wiring of various signals
The trouble here has reduced the project cost.
3) Strong anti-interference ability. Twisted-pair cable can effectively suppress common mode interference. Even in a strong interference environment, twisted-pair cable can transmit excellent image signals.
Number. Moreover, the use of several pairs of twisted pairs in a cable to transmit different signals respectively without interference with each other.

4) High reliability and easy to use. Use twisted pair cables to transmit video signals, and a dedicated transmitter must be connected at the front end, and a dedicated transmitter must be connected at the control center.
Receiver. This kind of twisted pair transmission equipment is cheap and easy to use. It does not require professional knowledge and does not require much operation.
Installation, long-term stable work.

5) The price is cheap and it is convenient to obtain materials. Because it uses the general 5  unshielded cable or general telephone line that is widely used at present, it is easy to purchase.
And the price is also very cheap, which brings great convenience to engineering applications.

Welcome to Zhuhai hanqin Cable Co.,Ltd  ,in this part, we will discuss the comparison of    different version HDMI.

Version 1.4 compared to version 1.3, the most obvious difference is the addition of the Ethernet function (HDMI Ethernet Channel) Support Audio Return Channel (Audio Return Channel) HDMI 3D function 4K*2K@30 video support More color space Micro HDMI connector, Type D Vehicle connection system Type E

Compared with version 1.4, there are no changes to the cable and connectors in version 2.0, so the cable in 2.0 is the same as the cable in 1.4, except that the chips of the Source and sink devices have changed. HDMI in version 2.0 is based on the 1.4 cable. , The signal equalization processing is improved through the device chip to achieve the transmission effect, which is similar to the addition of signal amplifiers to the devices at both ends.

Version 2.0 specifies that 4K is required, and 1.4 and 1.3 do not specify that 4K is required.
Version 2.0 supports 4K*2K@50Hz, 4K*2K@60Hz resolution
The transmission bandwidth has been increased from 10.2Gbps in version 1.4 to 18Gbps
Version 2.0 supports 21:9 aspect ratio/32 channels and 4 sets of audio streams/dual picture/CEC extension/dynamic sound and picture synchronization function
Compared with version 2.0, version 2.1 has higher requirements for wire technology, and the connector has been redesigned.

Higher video resolution supports a series of high resolutions and faster refresh rates, including 8K60Hz and 4K120Hz, enabling immersive viewing and smooth fast action details. Commercial AV, industrial and professional uses also support resolutions up to 10K.
Dynamic HDR support can ensure that each moment of the video is displayed with ideal values ​​of depth, detail, brightness, contrast, and wider color gamut-scene by scene or even frame by frame.
The ultra-high speed HDMI cable supports 48G bandwidth and supports uncompressed HDMI 2.1 functions. The cable also has extremely low EMI radiation, and is backward compatible with earlier versions of the HDMI specification, and can be used in conjunction with existing HDMI equipment.
eARC simplifies connections, provides greater ease of use, and supports the most advanced audio formats and the highest audio quality. It ensures full compatibility between audio equipment and upcoming HDMI 2.1 products.

The enhanced refresh rate function ensures a higher level of smooth and seamless motion and transition for games, movies and videos. They include:
Variable refresh rate (VRR) can reduce or eliminate lag, stuttering and frame tearing, resulting in a smoother and more detailed gaming experience.
Fast media switching (QMS) for movies and videos eliminates the delay that can cause a blank screen before displaying content.
Quick Frame Transfer (QFT) can reduce latency, achieving smoother latency-free gaming and real-time interactive virtual reality.
Automatic low-latency mode (ALLM) allows automatic setting of the ideal delay setting, thereby achieving smooth, lag-free and uninterrupted viewing and interaction.

The selling point of version 1.3 is to support 1080P high-definition picture quality
The selling point of version 1.4 is to support 3D function and Ethernet function
The selling point of version 2.0 is to support 4K ultra-high-definition picture quality

Note: Since the HDMI2.0 version does not have a new definition of the cable and connector, only the Source and Sink have been changed, so the HDMI2.0 cable still refers to and uses the HDMI1.4 version of the cable specifications and test standards, that is, if it passes 2 All HDMI1.4 cables of cat2 (cat2) can be used for HDMI2.0 transmission.

hello, welcome to zhuhai hanqin cable co.,ltd

In this article, we will discuss the cabling process’ affection on the performance

Cabling’s processing affection on the performance of HDMI：

Foam processing： take 50%，most important part in cabling use dB to shows the signals attenuation

Signal attenuation is closely related to impedance. Impedance matching and impedance stability are of great significance to attenuation. As can be seen from the above figure, it is very important to control the foaming degree to ensure stable impedance during the foaming process of the core wire.Now the new foaming machine can automatically control the temperature, so it can ensure the foaming stability throughout the whole process, while the old-fashioned machine is controlled manually, and the value of the static capacitance is adjusted every minute.

So, are there any employees who will help you keep an eye on the static capacitance to adjust the foaming degree in minutes? Obviously it is unrealistic. Go to the toilet and drink a glass of water and leave. Even if not, the night shift is too tired and doze off, the core wire control is not in place, and the core wire has a great impact on performance. This process cannot guarantee stability. , No matter how hard the subsequent process is, it will not help. In addition, the surface of the conductor is oxidized because of the skin effect during high-frequency transmission. Signals are transmitted through the surface of the conductor. If the conductive surface is oxidized, it means that the highway is full of stones, and the car must not drive fast. There is also the core eccentric problem, which will affect the capacitance distribution and produce the problem of electromagnetic field imbalance and seriously affect the signal. A few of this problem is because the mass production is not adjusted properly, and most of the problems are because the foaming mold is worn out and it is difficult to adjust the eccentricity. Open line.

Twisting process: the impact accounts for 5%

For twisting, ensure that the physical lengths of the two core wires are the same. In order to ensure the delay difference, that is, the signal can go from this end to the other end The transmission distance should be infinitely close.

The time for the signal to travel from end A to end B is called delay difference

The time it takes for the signal of a core wire in 1P to go from A to B

The time it takes for the signal of the other core wire in 1P to go from A to B

Internal delay difference (≤112ns, Cat2 standard) 1s=10^9ns，1 nanosecond is equal to one billionth of a second

At present, most factories can use the power pay-off rack to automatically control the pay-off force of the two core wires to ensure that the physical lengths of the two core wires are the same.

foil shield wrap processing: occupy 20%

The wrapping paper cannot be too tight or too loose. Too loose wrapping may cause signal crosstalk and reflection due to slitting of the aluminum foil, which will seriously affect signal attenuation. Too tight the package will cause the core wire to deform and cause serious electromagnetic field deformation, signal reflection interference, and also seriously affect signal attenuation. At present, a small number of factories use new machines to wrap paper. The new machines can automatically track the tightness of the aluminum foil to ensure that the strength of the aluminum foil for all signal pairs is the same, and the wrapping will not be too loose or too tight. However, most factories use old equipment, and the strength of wrapping paper is entirely based on the experience of the employees. Once a novice employee is used to operate it, quality problems are likely to occur.

Wrap (roll wrap): Aluminium foil wraps (rolls) the core wire in 360 degrees, the core wire does not rotate

Wrap processing, occupy 20%

Towing strap (oblique strap): The core wire rotates at high speed, and the aluminum foil is brought in by the rotating core wire

In addition, many factories currently use horizontal twisting and wrapping machines to complete the twisting and wrapping processes together. Because the horizontal twisting machine adopts the form of towing and wrapping, the production capacity is 2-3 times of the original (twisting and wrapping aluminum foil) process. However, the quality is low, and the aluminum foil is easy to loosen. There is also a 405 synchronous machine that also drags the aluminum foil while twisting it. This kind of machine is only suitable for ground wire insulation without pressing, suitable for wrapping aluminum foil + hot melt Mylar method

Total twisting (collection twisting) process: accounted for 5%

Total twisting (collection twisting) process: accounted for 5% Generally, the influence of twisting is not there. Pay attention to the wire mold that it should not be too small,which would squeeze the core wire braiding and extrusion process: 5% The two processes have little impact, so be careful not to crush the core wire. The sheath is half-squeezed to reduce the pressure on the inner core wire.

Process design: 15%

For example, the foaming degree of the core wire is generally designed to be around 40%, but some factories design around 50% of the limit, although the foaming degree is high, the dielectric constant becomes small, theoretically, the attenuation will be better, but we ignore a problem that the PE physics after foaming the strength and other properties deteriorate and the core wire becomes softer, and the higher the foaming degree, the softer the insulating part, which is susceptible to compression deformation during subsequent processing and affects the signal. In addition, the impedance value specification requires 100±10 ohms, and the design is about 100 ohms. Too high or too low impedance will affect signal transmission, TDR test is difficult, EMI test is not good.

1.3The influence of processing procedure on performance: When opening the aluminum foil, try not to cut the foam core wire. The length of the opening is controlled within 15mm. When opening the aluminum foil, be careful not to make the aluminum foil too loose. The wires required by EMI should be 100% girth welded shielding

This page we will introduce the working principal of different Pins of HDMI, you can check www.hanqin-cable.com for more other cable details.