With the HDMI 1.4 specification output, five types of HDMI Cable appeared immediately. The purpose of this article is to help to understand this abundance. Immediately I will say that the material is designed for the reader, which already has an idea of what HDMI is.

Therefore, I will stop at the most uplifting features of its design and use, as well as comparison with HDMI 1.3 cable.

By and large, there is no fundamental difference in the structures of the "old" cable 1.3 and "new" 1.4, and the differences that are available mainly concern the cable with Ethernet. And most differences do not apply to the cable as such, but to the new capabilities of the format itself, and are implemented in devices: signal sources and receivers. Moreover, some of these possibilities exist only on paper.

The new classification should in theory facilitate the user to select the desired cable by dividing the cable products according to the rate of data transmission and the pound capabilities.

In the near future, all manufacturers will switch to a standard system of symbols of all five types of products. Each product will be marked according to its type. Standardized marking can be several kinds: color, black and white, rectangular, round. The most important thing is the presence of such a marking is already defined by the cable belonging to the HDMI 1.4 category. At the same time, the "HDMI 1.4" itself can be absent!

1. standard HDMI cable

The standard HDMI cable is designed to work with most ordinary home components (DVD players, satellite TV receivers, plasma and liquid crystal panels, etc.) and is designed to transmit image signals with up to 1080i or 720p resolution. In fact, it is an old familiar, HDMI 1.3 "category 1", it is characterized by a reduced (compared to the "Category 2" cable) total bandwidth (3 m m m m up to 2,25 Gb/s and clock speed up to 74,25 MHz.

Attention! In some cases, at lengths of more than 2 - 3 meters, the correct transmission of signals 1080r and higher when using such a cable can be forgotten. The situation will depend on the quality of a particular copy of the cable, but when using this type, no one promised high speed data transfer. The visual degradation of the image signal can be observed even at smaller lengths. The cable of this type is designed primarily for connecting conventional sources and signal receivers.

This is the most bust type cable, for those who do not need high quality image and sound.

2. standard HDMI cable with Ethernet

This type of cable has the same capabilities as the standard HDMI cable considered above (1080i or 720p), but additionally is equipped with a specialized Ethernet HDMI data channel and is designed to combine different components in the network at a speed of up to 100 Mbps and communication of these components with the Internet. Ethernet HDMI Cable functionality is available if both connected devices support Ethernet HDMI. It should be noted that this cable supports the Audio Return Channel (ARC).

A typical Ethernet diagram of connections in an audio video system is shown in the following pictures:

Ethernet data channel capabilities

Standard connection of components without Ethernet HDMI

Standard connection of components with Ethernet HDMI

3. car HDMI cable

The new type of HDMI cable, designed specifically for vehicles, is able to work in tough conditions, such as vibration, high humidity and temperature changes. Designed to connect various multimedia devices in cars. One of the possible usage schemes is shown in the figure below (Fig. 4).

The new E-type HDMI connector with lock provides better fixing of the connector in the socket and prevents separation during operation. In pic. 5 presented View HDMI connector E-type, source:Http://www.hdmi.org/.

4. High Speed HDMI Cable

High-Speed HDMI Cable is designed to connect high-quality home components (Blu-ray players, HDD players, satellite TV receivers, plasma and liquid crystal panels) and is designed to transmit image signals with a resolution of 1080r and above (up to 4 K-4096 × 2160, 24Hz). The total bandwidth (per 3 channels is RGB) reaches 10,2 Gb/s and the allowed clock frequencies up to 340 MHz. Suitable for connecting any sources and receivers of the signal. Has Backward compatibility with all types of HDMI, provided you use A-type connectors. The main differences from the standard hdmicable are in the section and material of four twisted pairs, the quality and design of the dielectric twisted pairs, the shielding of pairs and the general. Naturally, all this affects the final price of the product.

From my point of view, this is the most suitable cable in most situations, provided, that your components do not support HDMI 1.4 Ethernet or you are not going to connect home network and Internet to your audio video system in the future. This is a significantly higher quality cable compared to Standart and Standart with Ethernet. The difference in the image of a good high speed cable, compared to the Standart cable, is usually noticeable even on inexpensive components.

5. High Speed HDMI Cable with Ethernet

This type of cable has the same capabilities as the previous type High Speed HDMI Cable, but has an additional specialized HDMI Ethernet transmission channel to combine different components in the network at speeds up to 100 Mbps and communication of these components with the Internet. Ethernet HDMI Cable functionality is available if both connected devices support Ethernet HDMI. There are no such devices in Russia yet. The first components should appear only at the end of 2010. This is a universal cable with all the conceivable capabilities that can provide the HDMI 1.4 specification today. It makes sense to purchase with the "sight" for the future.

Several simple tips on the choice and use of the cable.

First of all, we will determine the choice of one of the four types of HDMI cable. The fundamental choice occurs between high speed (more expensive and better) or Standart (cheaper and somewhat worse). Further easier-you should decide whether to connect to the Internet or local computer network of your components. In this case, the components must support HDMI 1.4 with Ethernet, otherwise the exchange of HDMI data will not be possible. And again there are two options, different quality capabilities,-high speed with Ethernet (better) or Standart with Ethernet (cheaper). On the packing of the cable can be provided information about the guaranteed signal transmission range 1080r, and then everything is simple: the further-the better. Cable conductors must be maximum section, but this information on the package does not usually indicate. You can evaluate the quality of the cable and on some indirect signs. In general, the thicker and harder the cable, the better the transmission of sound and image. This, at first glance ambiguous criterion, there is a rather serious physical justification (about this in the second part of the article). I especially want to stop on the choice of cable for laying in the wall or ceiling: The technique very quickly develops and has the sense to lay the cable only with maximum bandwidth-high speed or or

Very important! Never switch the components to HDMI when the equipment is on, it can fail it! Do not allow sharp cable bends, because. This leads to a change of wave resistance and can in some cases violate signal transmission.

In this part will go a story about the characteristics and difference of the HDMI cable designs.

The HDMI 1.4 standard clearly separates the cables into two groups depending on their characteristics. This division was previously (in the HDMI 1.3 specification-"category 1" and "category2"), but not all manufacturers indicated it. Now it will be called "Standart" and "high speed". What is the difference between "Standart HDMI 1.4" and "High Speed HDMI 1.4"? Please refer to the HDMI 1.4 specification. Having examined Table 1 (tab. 1) we see that the standard HDMI 1.4 cable is much inferior to the High Speed HDMI 1.4 cable by frequency response and, accordingly, the transfer rate of information.

Comparison of High Speed HDMI 1.4 and standard HDMI 1.4 cable.

In the figure below (Fig. 5) this difference is expressed graphically. I pay attention to the fact that in the vast majority of cases

Indicate the total bandwidth, and it will be three times higher than each of the channels. Marketing!...

The tables give a comparative analysis of the maximum physical capabilities of the format and HDMI 1.3 and HDMI 1.4 cable is highlighted by the blue dotted. As we can see, they are not different. All that is highlighted by the Brown dotted refers to the possibilities of formats. Audio output: the difference between high quality cable (without Ethernet) HDMI 1.3 and high speed (without Ethernet) HDMI 1.4 there is no.

More detail on the constructive differences and their impact will stop later.

HDMI 1.4 Cable With and Without Ethernet: What is the difference?

Tabl. 3 S

If we see what is different in design standard (or high-shell) HDMI 1.4 cable without Ethernet and a standard (or high-shell) cable with Ethernet, then the 5-way-way unpacked at 14, 17 and 19 contacts of the connector (tab. 3). The same pair sends the arc signal (Audio Return Channel).

This photo shows very well, HDMI 1.4 cable design difference with Ethernet and HDMI 1.4 Without Ethernet

Fifth twisted pair with screen, HDMI 1.4 with Ethernet. These three wires are replaced by twisted shielded pair, HDMI 1.4 Without Ethernet.

Standard HDMI cable and High Speed HDMI Cable.

Tabl. 4

A very interesting question about the difference of standard HDMI 1.4 cable and high-speed HDMI cable 1.4, taking into account that the desoldering of connectors and the number of physical conductors they have equally (Table 4). In the meantime, let's see what some of the manufacturers offer, and what options of HDMI cable designs are used.

Options for the appearance of HDMI cable. Not yet marked and without colorful packaging.

In the manufacturer's offer, one of the specification options for making HDMI cable looks like this: version: HDMI 1.3b/1.4 (optional)

• AWG: 30/28/26/24 (optional)

• Plated: Gold/nickel (optional)

• Length: 1m to 20m (3ft to 60ft)

• Braid: black/white/blue/gray… (optional)

• Conductor: BC-bare copper, TC-tin copper, SC-sliver copper

As we see, the manufacturer offers various options for cable, connectors, etc. D., in general, "any Caprice for your money." Here comes a very important factor-the cost, with which the characteristics are connected and, in the end, the resulting quality of the cable. Unfortunately, in some cases, cable manufacturers (ordering their goods from manufacturers) put in the final value of the margin "from free". As a result, both high level products and very mediocre, can be close in price, and in some cases the price may not correspond to the quality at all. In many ways because of such "paradox" is common misconception that all cables are the same and do not need to overpay unknown for what. The cost of production of HDMI cable can be very different due to the features of technology from various manufacturers, in particular, due to manual soldering and its quality (do not forget about 38 contacts)) Save, given the mass production, try literally on everything, first of all on copper, replacing it with cheaper aluminum and lowering the cross section of copper conductors. Some save on individual ground conductors twisted pairs, which significantly reduces the noise protection of such a product. Signal 1080r on such a cable, depending on the source, receiver and external conditions may not "pass" and for five meters, with the declared fifteen. In some cases, working capacity at large lengths, unfortunately, can only be checked in an experienced way.

The main difference of standard HDMI 1.4 Cable, in comparison with high speed, is in sections of twisted pairs, in precision of cable construction, as copper, in service conductors, as well. With the increase of the conductor section to a certain limit, signal transmission improves. But on this path there are restrictions associated with the physical dimensions of the cable, its flexibility and complexity of soldering. The cross section of conductors used in HDMI cable is usually no more than 24 AWG (0.205mm2 S), Very rarely 23.5 AWG (0.22mm2 S), Single cases 22 AWG (0.32mm2 S). From well-known manufacturers represented in Russia, conductors of the largest section of the cable tchernovaudio HDMI pro ic-23 AWG (0.258mm2 S).

Very important for data transfer speed has precision of manufacturing twisted pairs. The uniformity and thickness of the dielectric, compliance with the diameters of conductors are very important conditions to ensure the normalized value of the wave resistance and minimization of the signal reflections reflections on The uniformity of the twist step of twisted pairs has a very strong effect on cable security. The level of cross-interference of transmission channels in nature and signal structure depends on the quality of the shielding of twisted pairs, which ultimately determines the quality of transmission of video signals. The external dual screen allows you to additionally protect twisted pairs and service conductors from external floods.

Shielding cables in itself represents a complex theoretical and practical task. In general, for frequency bands of transmitted signals with which the HDMI standard works, the following points are fair:

• The thicker the wire and foil material, the better as it ensures increased conductivity.

• The longitudinal foil setting is better than the spiral one, but it is hard enough and hard to bend.

• The outer screen in the form of Braid and foil, or double braid, is much better than the single screen, even if two shielding layers are not isolated.

• The best configuration for cables with a screen in the form of Braid and foil when the braid is against the conductive side of the spiral foil.

• Individual twisted pairs in a common shielded cable shall be placed in individual screens to prevent capacitive cross interference between signal conductors, and the screens themselves shall be closed.

It is desirable that the specific resistance of the conductor material is minimal.

From the above, it follows that high-quality HDMI cable is almost impossible to make a thin and flexible. In the photo below, you can see the comparative thickness of three HDMI:

Two high speed and one standard. To determine which one is standard, I think, will not be difficult...

Soldering also contributes to the work of the cable. To experiment with the quality of soldering and its influence on the transmission of HDMI signal did not occur, but with a defective cable from different manufacturers had to face and be surprised that the cable is is is In the pictures below (Fig. 9) you can see various options for soldering a defective cable from different manufacturers. According to the reviews of the people relevant to the trade, some part of the HDMI cable after 1-2 years went out of order. One of the most likely reasons is poor soldering.

Thus, a high-quality High Speed HDMI Cable is a fairly complex design that requires high technological culture at its manufacture. Therefore, to the choice of a cable, especially for stationary, and the more hidden, the wiring should not be suitable for the principle "the cheaper, the better". Look at the cross section of twisted pair conductors, many manufacturers of it indicate and better if it will be at least 0.205mm2 S. It is desirable that all screens are copper. As an example of a successful, well thought out and correctly implemented cable design, you can hang tchernovaudio HDMI pro IC (Fig. 10). In the photos (Fig. 10 and fig. 11) two different designs of High Speed HDMI Cable can be seen. The price of these products is very close, but the complexity of the design and the quality of the materials used are different. In pic. 12 shows the typical HDMI standard cable filling.

Sample Design High Speed HDMI Cable without Ethernet

Pic. 13. Examples of network construction, switching with an HDMI cable with Ethernet.

All connections between A/V components of the home network in the near future can be made using an HDMI cable with Ethernet (Fig. 13).

Audio Return Channel capabilities (ARC)

Pic. 14

The Audio Return Channel supports Dolby Digital, DTS and PCM standards and is an analog of standard S / PDIF connection. When using it, you do not need an additional cable to transfer sound from the TV to the Home Theater Receiver. About the work and features of arc, you can find out from the link:Http: // www. Hi -fi.ru/forum/ forum87/topic67176/

Final Part "HDMI 1.4"

Especially for those who think that the cable can not affect the signal quality. The Legend of the figure.

Hot disputes on this topic constantly arise in different forums. Many believe that the signal by HDMI cable can either be transmitted or not transmitted, because. It consists of 0 and 1. in fact it is not quite so. We will stop at some problems of signal transmission to HDMI (DVI) formats.

First of all, do not forget that any electrical signals, including "digital, in the real world are analog, that is, changing continuously and for a certain amount of time. Although sometimes very little time. The main difference is that

Conditionally called "digital" signals, from conditional "analog" is a much wider spectrum of frequencies,

Taken first. In other words, by hdmi cable (as in any other), the signal is transmitted in analog form, that is, in the form of electric currents from very low (i.e. DC) to very high (many tens of GHz) frequencies.

Without entering into details, from an electrical point of view, when transmitting digital signals, you have to encounter the same problems as when transmitting analog signals: loosening on the amplitus the head of the fronts (reducing the level of high-frequency components), noise.

When attenuation of a useful signal, distortion and enrichment of its interference, part of the information is lost. And since the means of monitoring the correctness of data transmission (e.g., the control amount), unlike the transfer of data in the computer, is not used, then when reaching a certain level of errors, you can get distortion and interference, a well-visible image-"Moving" Pixels, dots, stripes). This is what the effect of the cable is.

I will provide some materials on this topic. They are partly related to the problem of connecting to DVI, but all the below can be safely attributed to HDMI, and to any other format of transmission of broadband signals. There are many electromagnetic processes that affect the properties of the transmitted signal in the cable. For the first time with the effect of the cable line on the transmitted electrical signals encountered when laying the first telegraph cable along the bottom of the La Manche Strait. The fifty-kilometre section of the cable was first unable to transmit even the slow signals of the manual telegraph-so great was the attenuation and dispersion of the signal in. To date, the problems of half-time limitations have, of course, been solved, but nevertheless, similar physical processes show themselves at a different level. If we transmit a "digital" signal, we must always determine the conditions of its "discretion". When transmitting a signal, it is considered that if its input voltage of the receiver is at the moment above one certain level, the receiver considers that it is the level of "logical 1" "if below another particular one is" logical 0 ". At the output of the source, the signal is a sequence of rectangular pulses, and when distributed over the cable, such a signal is distorted. Its attenuation occurs, I.E. Reducing amplitude (due to losses in conductors, losses on radiation and polarizing processes in dielectric), the fronts (due to the ultimate bandwidth associated with frequency-dependent loss), distortion of pulse form as a result of dispersion, mutual influence of signals of different twisted pairs and external floods. In addition, in the cable, resonance phenomena and reflections of the signal from heterogeneity are possible, which also leads to the distortion of the pulse form... if we connect the oscilloscope to the Next, in the course of distribution in the cable, they will gradually blur, the form of them will distort. With too long or poor quality cable at the input of the receiver, the signal will be very different from the one that can be observed at the input of the cable. Distortions can be so large that the receiver will not be able to take such a signal according to the criterion of its "discretion".

Interference can also have a great impact on the stability of the digital signal transmission. A fundamental solution to the problem of anti-interference protection is the so-called "differential" (or "balanced") transmission. For each line, two wires are used, one of which is sent a direct signal, and the other is an inverted copy. Thus, at any time, the sum of such signals is ideally zero, and the difference is the double value of the signal at the input of each line. At the receiving end of the line is placed a special device-a differential receiver, which just subtracts one signal from the other. Imagine now that two conductors transmitting such signals are very close to each other. The external field, which leads to interference, will create practically the same interference signals in these conductors. N. Synphase interference. The receiver will subtract them from one another, as a result at its output the signal interference will be close to zero, and the useful signal will be doubled. The work of the differential line and receiver well explains the following figure (Fig. 16):

Pic. 16 box

On the upper part of the picture shows the signals acting in the line. The green color is displayed-a useful signal in the direct conductor. The blue one is in the anti-phase conductor, and the red one is the interference signal, the same for both conductors. The bottom of the picture shows a signal at the input of the difference receiver-it is seen that the useful signal will be doubled, and the signal of the blue interference will be almost zero zero.

In order for the conductors to be located nearby, and external interference created in them as close as possible signals are used to twist the conductors into pairs, which are usually used in the way. If such a pair is placed in an external screen, the floods on the line will be reduced even more. As a result, you will get a cable with a fairly high noise protection. This is how dvi and hdmi cables are made, designed to transmit a very wide frequency band of signals. In the picture below (Fig. 17) you can see a simplified circuit of the transmission line for a single shielded twisted pair.

Pic. 17

The higher the maximum frequency of useful signals in the cable and the higher the frequency of possible external interference, the smaller there should be a twist pitch of the pair and the smaller the distance between between between But, on the other hand, the same parameters determine the wave resistance of the line, dispersion and loss in it. Therefore, there are certain optimal values of insulation thickness of conductors and twist step, which with good noise protection provide and required electrical parameters of the line. However, in the world there is nothing perfect and even the best cables are still not perfectly protected from interference (for a number of reasons, incl. Precision of manufacture) and have quite a certain attenuation. Therefore, the interference, unfortunately, penetrates even the shielded cables, and the own electrical parameters of the cables also affect the signal. What can this lead to? Let's see the following figure (Fig. 18):

Pic. 18

The upper oscilloscope shows a signal at the output of the data transmitter. The second is the signal at the output of the receiver when it is directly connected to the transmitter output. It can be seen that the restored signal has an accurate binding to the timeline. The third oscilloscope corresponds to the fact that you can observe at the output of a long cable in conditions of great external interference and the presence of disagreements of the wave resistance of the cable and and load What will be at the output of the signal receiver, shows the last oscilloscope. The restored signal, in addition to having received a temporary delay, also changes its duration and location of fronts and drops in time, that is, accidentally depends on the value of the device. And this is jitter, the storm of all digital data transmission systems. Its appearance leads to the fact that a strict time grid is broken, defining in digital devices all processes of signal processing and conversion. The result of this is visible and audible distortion of the image and sound. Of course, in real conditions, interference and distortion of transmission will not be as high as on the above example, but they are available in any case, only their level and properties. Linking source and receiver of digital signals. Any hardware and software means of jitter suppression have limitations in application, and the quality of their operation is directly associated with its original level-the greater the value of jitter, the lower the value In simple cases, a large level of jitter leads simply to some decrease in image and sound quality, in "clinical"-can cause serious violations in the work of digital systems.

In differential transmission lines, jitter can occur not only under the influence of external factors. Any asymmetry in the cable, incl. And the difference in the signal delays inside the pair, leads to the appearance of a synphase component of the signal. At the same time, the amplitude of the differential component is reduced. The trouble is that differential and synphase signals have different spread rates and different loss factors, therefore, depending on the form and spectrum of the transmitted signals, the resulting error leads to an additional component of the phase jitter (jitter), corellated with the signal. Note that the synphase components themselves do not make jitter into the signal. Problems begin when converting. The imperfect difference transformation of components significantly spoils the signal, and the unidentity of twisted pairs in the cable further aggravates the situation. In the image transmission systems on dvi and hdmi interfaces, the recovery of the tactic frequencies in the display device (monitor, panel) is done with the help of phahr systems,,, flood on connecting cables, but also the difference in the delay of the transmission of clock frequencies and information signals. That is, such systems are sensitive to both cable protection and its delay and dispersion. In the experience of silicon image, dvi cables with a length of 2 meters work normally, however, the quality can significantly deteriorate with an increase in length to 5 m (and especially up to 10 ("Digital connection of lcd monitors: dvi quality tests at ati and nvidia" d. Chekanov, Lars veinand).

Many problems of digital signal transmission have been investigated and described for quite a long time and everyone willing to study this issue in more detail, i recommend the article: "digital connection of lcd monitors monitors monitorsHttp://www.thg.ru/graphic/20041203/tft_ connection-01.htmlIs)

The increase in the level of jitter, caused by the above phenomena, leads to the appearance of visually noticeable defects in the image. Jitter, caused by the discrepancy of the initial phase of the sampling rate in the adjacent lines, leads to additional noise at the video signal changes. The biggest errors are observed for higher frequency and amplitude signals.

How is this all visually displayed on the screen?

When transmitting the image signals, the greater noise level is observed at signal changes (repeatedly exceeding the noise present on a flat background). This is especially expressed when playing the contrasting transitions of the frame (edges of objects, grilles, etc.), as well as images containing a large number of small parts (back plans,,,

Etc.). There is a subjective feeling of reducing the depth of the image and reducing the contrast. The black color becomes less black. If you look carefully at the dark places of the frame, you can notice the noise in the form of small points. This is the reason for reducing the contrast of the image.

The image can look less stable, it is shown in "moving pixels", especially noticeable on leaves or complex rear plans with a large number of elements, especially when the camera moves. In addition, there is also color rendition, which is especially visible on projection systems and plasma panels with a large diagonal. Distortion of color is observed, first of all, on complex stories. Colors visually look more bleached

And less clean. In some cases, the brightness and sharpness of the image are noticeably reduced. The sharpness is reduced as a result of the blurring boundaries of the contours of objects, although some see such a picture as more "film" and "analog".

At the last stages of signal degradation appear. "Flies" and stripes. Then there is a loss of synchronization and the image disappears.

Pic. 19

But before this "happy" moment is the gradual degradation of the signal associated with the above processes (fig. 19).

Thus, the data transmission channel, in our case, is an hdmi cable, has a significant effect on the quality of transmission of image signals even on small lengths, and not to consider its its its

In conclusion, i want to say that the last three years had the most direct relevance to the testing of hdmi cable and came to the following conclusions:

1. The difference in the quality of the cable is visually visible even on tvs with a diagonal of 26 inches.

2. It is difficult to tell in advance at what length a complete or partial degradation of the signal will occur.

It depends heavily on the cable itself and the combination source/receiver signal. The same cable can work perfectly on one combination source/receiver, issue problems in the form of the worst picture on the other and do not work at all on the third. When testing the 20 m of the hdmi prototype from tchernovaudio, except for laboratory studies, several dozen source/receiver options were checked for performance testing, and the test was performed. providing 100% performance (already about 150 hardware combinations have been tested today, for the 1080p signal). Looking forward to possible questions about the instrument control (which was conducted outside russia) and the additional need for "field" tests, i will immediately answer that the final user will not be pleased if and on his system, however, there will be a problem.