Materials used in HDMI and its characteristics

Hello, welcome to Zhuhai hanqin cable co.,ltd

In this page, we will discuss the materials used in HDMI and its characteristics.

FPE Foam-PE   with proportion 0.7g/mm³

Often use America material 3485 as the FPE, before foaming, the PE’s permittivity is about 2.3, PE after foaming, the permittivity comes down and the attenuation become lower while the transmit signal become better. the more complete the PE foaming, the lower the permittivity and the better the transmit, but the physical performance also come down. e.g: the hardness come down and the stretch become shorter. Normally, chemical foaming degree is about 30-50%, often use 40%. we use PE+ foaming agent to processing the FPE, foaming agent release lots of small foam after high temper , these small foam spread among the PE and then make the FPE. Often, the higher temper, the more complete foaming. Foam wire use in HF signal transmit.

HDPE  0.92-0.95g /mm³

Normally use America’s 3364 PE, use in electrical wire insulation, drain wire insulation, not use for foam PE. price is about 20% lower than 3485.

 pvc 1.48g/mm³

low price,good insulation,anti-corrosion and easy processing. It has been widely used in cable jacket

TPE 0.9-1.25g /mm³

it is a kind of high elastic rubber,strong and elastic materials. It can be used in cable jacket, price is higher than PVC.

 

wire OD use ID (Inner Diameter),middle diameter useMD,outer diameter use OD As the surface of the jacket, there are frosting, half-frosting, polished kinds.

 

 

Wrap material: Aluminum foil can also be abbreviated as AL, sometimes customers will write S.AL refers to single-sided aluminum foil, and D.AL refers to double-sided aluminum foil

AL/Mylar AL-Foil AL/MY with proportion of  0.05g/mm (experience data ) has characteristics as follow:

Use 12u aluminum layer and 10u PET transparent light film, plus 3u glued together, the total thickness is 25u. The confined metal space can shield signal interference/crosstalk. The aluminum foil wrapped (rolled) uses this principle to achieve the shielding purpose. The default overlap rate of the wrapped aluminum foil is more than 25% to ensure the shielding effect.

PET Mylar transparent film 0.04g/mm (experience data)

Generally used for insulation and isolation, without the shielding effect of aluminum foil or copper foil. The thickness is generally 20-25u

Al+ PET 0.09g/mm (experience data)

The above two materials are made together. PET is slightly wider than aluminum foil. The original process of wrapping aluminum foil and then PET becomes directly wrapping fin aluminum foil, that is, one process completes the work of the previous two processes, but fin aluminum foil is harder and more expensive. It is also more expensive than the combined materials of the above two processes, so there are not many applications.

copper foil

The shielding effect is better than that of aluminum foil, and the price is higher. Generally, the 360-degree copper-clad ring welding of the joint is shielded on the line that requires EMI. At present, it is also shielded by ring welding of tinplate. The thickness is generally 35u or 55u

ALMG al alloy ‘s proportion is 2.7g/mm³

The conductivity of aluminum is better than that of steel, and the conductivity is about 60%. However, the strength of aluminum is poor and easy to break. Adding a small amount of magnesium can strengthen its strength to a certain extent, and the price is about half lower than that of copper. The shielding effect is worse than copper. Weldability is poor (can’t be welded), usually need to add a BC/TC/CCS to weld on the joint shell to ground.

BC TC ‘s proportion is  8.9g/mm³

Like the previous conductor introduction, tinned copper and bare copper have similar shielding effects, which are much better than aluminum-magnesium wires. They are expensive and easy to solder. You don’t need to add a ground wire to solder. One group of braided nets can be drawn as the general ground wire welding.

As shown in the figure below, the red dot marks the intersection of the two strands of the woven net, counting straight to the right to the 9th intersection. The distance between 1-9 points is the pitch of the 16-spindle woven net. If it is 24 spindles, then Measure to the 13th intersection; The number of knitting mesh refers to the distance of one inch (2.54CM), and the number of intersections counted by the straight line is the number of meshes. The larger the weaving pitch, the smaller the mesh, the lower the shielding rate and the worse the shielding effect. At present, HDMI26/28 weaving 168 nets or more generally use 24 ingots to weave

 

In addition, because of the non-shielding effect of the cotton net or metal material net woven outside the wire, the function of the outer net is generally to be beautiful, wear-resistant, and tensile. Woven net is represented by B, +ADB in English: A is aluminum foil, D is ground wire, and B is shielded net

HDMI materials and functions

Hello, welcome to Zhuhai hanqin cable Co.,Ltd   In this article, I am going to discuss the structure materials of HDMI and their difference.

 

Note: supper CCS has high proportion of copper, so, it has higher conductivity but its cost is not so lower than BC. HDMI ’s CCS conductors’ conductivity is about 18% . Conductors often transmit signal, and the earth wire only for take out the electromagnetic interference. Braiding material is for shielding the interference as well as flow deflector.

American wire gauge, use for conductor size, HDMI common size as below:

Note: different manufacturers with different ID, no need to be the same, just pay attention to the conductor size is ok.
HDMI’s total strand cores OD=foam insulation wire*5.2, e.g.: 30AWG conductor’s foam insulation ID is 0.7mm, then the total stranded core OD =0.7*5.2=3.64mm
OD after braiding=single braiding OD*5+ total stranded core OD, eg: the braiding materials AL’s OD is 0.12mm,after braiding=0.12*5+3.64=4.24mm

if the conductors is for transmit HF signals, then often use 7 stranded cores or 19 stranded cores. for the 7 cores, one inside the 6cores which strand around the center 1 core. If it is for 19 cores, then there is 1+6+12. Theoretically, both single cores or multi cores, they are the same.

Advantage of multi-cores:   softer and it can be used even some conductors has broken
Disadvantage: more complicated to produce and more cost not as stable as single core, so, mostly use single core or 7 cores, seldom use 19 cores
for the more cores, the harder to make it.

Also, why 1/0.404BC and 7/0.16 are both 26AWG? Because they count it by section. the bigger AWG, the smaller size it is. 7/0.16mm can be written as 7/34AWG. Earth wire can use D or D.W (Drain Wire)
 

Some professional words and testing method of HDMI. 27/06/2021

Welcome to Zhuhai Hanqin Cable Co.,LTD  , in this article, we will discuss the HDMI testing method and some professional words.

 

1. TV testing: Using TV practical operation, if audio and video normal, then pass. But, due to the different compatibility of different brand engine and TV, it might be ok in this engine or TV, but not ok in the others. Also, some good quality TV has better performance, it can use this cable which can not in other devices.

2.1 TDR Test: TDR is the abbreviation of Time-Domain Reflectometry, which is a kind of technology called time area refraction, a kind of remote measuring tech of reflection wave. HDMI use this measuring method to tell the condition of the signal wire’s signal transition, a kind of quantized parameter standard. In short, it tells the quality of the cable.

2.2 Professional word “attenuation”: When the signal transmit in the media(dielectric),part of its energy would be transferred into thermal energy or be absorbed by the media or be reflected, which would make the signal become weak. we call this attenuation.

2.3 Professional word “ Impedance”(IMPZ): Means the ratio between voltage and electric current of each wire. If one of them is not stable, the electromagnetic field is also not stable, and this would cause bigger impedance, which would cause loss of signal transition. There are many factors that affect impedance, like dielectric constant, dielectric thickness, foil thickness/tightness

2.4 Professional word “Matching Impedance”: the wires impedance need to match each other, also the connector’s impedance. Just like the screw and nut, only with tolerance can it be assembled well. We can understand it like this: when the water pipe was stepped, the water pressure inside the pipe change, and the water spray out at different position. If the water can not get to the specific position, it fails.

2.5 Professional Word: TDMS Transition Differential Minimized Signaling, abbreviation: TDMS its special performance is that, one conductor is positive pole, another is negative pole. By this way, it can transmit with good anti-interference. When two wires twisted together, the signal transmit with equal, same but opposite electromagnetic. They would offset with each other, which would improve the transmit quality, which would improve dependability of HF transmit. Of course, the two wire must be the same specification. At present, most HF transmit use this kind of method

 

HDMI connectors models and PIN position

Pin 18 is for providing power,if there is one bigger electrical wire, it should connect to this Position

 

Take HDMI AM-AM as example 1-12 is for data and time channels,2/5/8/11 four pins is for earth wire 14/19/17 is for independent ethernet channel,17pin is for earth wire Normally, the earth wire use PE insulation If one group of signal wire has problems, we can connect them to the 14/17/19 Pin, in order to guarantee the image data. but if more than one group signal wire has problems, there would be nothing we can do about it.

 

 

 

 

 

 

 

 

 

Some mistake operation would cause high impedance,which would affect the wire signals also the iterference signal of EM:

 

bad proccessing would affect the performance of the wire signals.

For each pair of signal wires,the lighter damage of foil shield, the better performance. That means on condition of being well welded, the short cut in the foil shield , the better signals,also, is better not to loose the uncut part of the foil shield.

short introduction of HDMI working principal

In the coming weeks Zhuhai Hanqin Cable will explain details the working principal of the HDMI

High Definition Multimedia Interface, is called HDMI is a kind of digital to video/audio connector technology,mostly use high definition
movie play: home theatre,computer,DV device  Principle of movie play: human’s eyes has speciality of”vision suspend”,which means that, when our eyes watch a photo or object, it will not dissappear within 1/24 second. Using this principle,before this photo dissappear we play the next one,it will make us fluent vision. That is why most movie use the play speed of 24pcs of photo/second. If it is slower than that speed, it will shows standstill.

For more details, you can browse our website: www.hanqin-cable.com