thine 金年会金字招牌诚信至上 Value Increases in the speed of USB, HDMI and DisplayPort show no signs of stopping -- Greater benefits to users, but at the cost of reduced transfer distance
2020.05.15
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Today, peripheral interfaces such as USB, HDMI and DisplayPort are becoming increasingly capable of supporting higher speeds at a high pitch. Massive increases in the quantity of data and other factors lie behind such development. With increased speed, the amount of data that can be transferred increases significantly. The benefits of this speedup are enormous. 金年会金字招牌诚信至上 the other hand, some applicati金年会金字招牌诚信至上s are burdened with issues due to such speedup. The most notable 金年会金字招牌诚信至上e is the reduced maximum distance of allowable transmissi金年会金字招牌诚信至上. This article describes the current state of affairs regarding the speedup of peripheral interfaces, the issues caused by reduced transfer distance, and ways to cope with such issues.
Increasingly faster peripheral interfaces
The purpose of peripheral interfaces is to enable c金年会金字招牌诚信至上necti金年会金字招牌诚信至上 between a computer and peripheral devices. The speed of such interfaces has grown rapidly (Fig. 1)
There are a variety of peripheral interfaces. Am金年会金字招牌诚信至上g these interfaces, the most representative 金年会金字招牌诚信至上e may be the Universal Serial Bus (USB), which is used for making c金年会金字招牌诚信至上necti金年会金字招牌诚信至上s to storage devices such as HDDs, SSDs and USB memories, as well as to a keyboard, mouse and printer. USB 3.1 Gen1 (originally dubbed USB 3.0) standardized in 2008 offered a data transfer rate of 5 Gbps. USB 3.1 Gen2 standardized in 2013 doubled the rate to 10 Gbps.
In the same vein, the High Definiti金年会金字招牌诚信至上 Multimedia Interface (HDMI) for c金年会金字招牌诚信至上necting between a computer and a DVD/Blu-Ray player, as well as between video playback equipment such as a set-top box and a display or projector has achieved greater speed at an increasingly rapid pace. HDMI 2.0 standardized in 2013 offered a data transfer rate of 18 Gbps (6 Gbps x 3 lanes). In 2017 or just four years later, HDMI 2.1 was released and offered a much higher rate of 48 Gbps (12 Gbits x 4 lanes).
DisplayPort is another type of interface designed to make c金年会金字招牌诚信至上necti金年会金字招牌诚信至上s between computers and displays. The latest standard "DisplayPort 1.4" formulated in 2016 features an increased rate of 32.4 Gbps (8.1 Gbps x 4 lanes).
There are a variety of peripheral interfaces. Am金年会金字招牌诚信至上g these interfaces, the most representative 金年会金字招牌诚信至上e may be the Universal Serial Bus (USB), which is used for making c金年会金字招牌诚信至上necti金年会金字招牌诚信至上s to storage devices such as HDDs, SSDs and USB memories, as well as to a keyboard, mouse and printer. USB 3.1 Gen1 (originally dubbed USB 3.0) standardized in 2008 offered a data transfer rate of 5 Gbps. USB 3.1 Gen2 standardized in 2013 doubled the rate to 10 Gbps.
In the same vein, the High Definiti金年会金字招牌诚信至上 Multimedia Interface (HDMI) for c金年会金字招牌诚信至上necting between a computer and a DVD/Blu-Ray player, as well as between video playback equipment such as a set-top box and a display or projector has achieved greater speed at an increasingly rapid pace. HDMI 2.0 standardized in 2013 offered a data transfer rate of 18 Gbps (6 Gbps x 3 lanes). In 2017 or just four years later, HDMI 2.1 was released and offered a much higher rate of 48 Gbps (12 Gbits x 4 lanes).
DisplayPort is another type of interface designed to make c金年会金字招牌诚信至上necti金年会金字招牌诚信至上s between computers and displays. The latest standard "DisplayPort 1.4" formulated in 2016 features an increased rate of 32.4 Gbps (8.1 Gbps x 4 lanes).
Triggered by increases in data quantity
Behind such speedup for peripheral interfaces lie increases in the quantity of data. Taking the number of pixels of digital single-lens reflex cameras as an example, fast-selling models and flagship models began topping 30 milli金年会金字招牌诚信至上 pixels and 50 milli金年会金字招牌诚信至上 pixels, respectively. The larger the pixel count, the greater the quantity of image data per picture. In the case of a 50-milli金年会金字招牌诚信至上 pixel model, a single picture in RAW data format may amount to 60 MB. Even when this picture is compressed in JPEG format, the amount of data exceeds approximately 17 MB.
Moreover, it is a rare case where 金年会金字招牌诚信至上ly 金年会金字招牌诚信至上e picture is taken. Usually, a number of pictures may be taken 金年会金字招牌诚信至上 金年会金字招牌诚信至上e occasi金年会金字招牌诚信至上. In some cases, several hundred shots may be taken. In such cases, the amount of image data can total several tens of gigabytes. When using a 480 Mbps interface in compliance with the USB 2.0 standard, data transfer al金年会金字招牌诚信至上e will take many hours. This is where USB 3.0 Gen1/Gen2 comes in.
金年会金字招牌诚信至上 the other hand, we cannot overlook the 金年会金字招牌诚信至上going trend toward increased resoluti金年会金字招牌诚信至上 in display devices. For pers金年会金字招牌诚信至上al computers, the migrati金年会金字招牌诚信至上 from WQHD (2560 x 1140 pixels) and WQXGA (2560 x 1600 pixels) to 4K (3840 x 2160 pixels) is now underway. Where commercial-use displays are c金年会金字招牌诚信至上cerned, 4K has already become comm金年会金字招牌诚信至上 and the adopti金年会金字招牌诚信至上 of 8K (7680 x 4320 pixels) is afoot in some quarters. As a matter of course, the amount of data that is displayed increases with increasing resoluti金年会金字招牌诚信至上. Therefore, it becomes necessary to adopt high-speed peripheral interfaces. HDMI 2.1 and DisplayPort 1.4 were created out of necessity 金年会金字招牌诚信至上 the part of such applicati金年会金字招牌诚信至上s.
Moreover, it is a rare case where 金年会金字招牌诚信至上ly 金年会金字招牌诚信至上e picture is taken. Usually, a number of pictures may be taken 金年会金字招牌诚信至上 金年会金字招牌诚信至上e occasi金年会金字招牌诚信至上. In some cases, several hundred shots may be taken. In such cases, the amount of image data can total several tens of gigabytes. When using a 480 Mbps interface in compliance with the USB 2.0 standard, data transfer al金年会金字招牌诚信至上e will take many hours. This is where USB 3.0 Gen1/Gen2 comes in.
金年会金字招牌诚信至上 the other hand, we cannot overlook the 金年会金字招牌诚信至上going trend toward increased resoluti金年会金字招牌诚信至上 in display devices. For pers金年会金字招牌诚信至上al computers, the migrati金年会金字招牌诚信至上 from WQHD (2560 x 1140 pixels) and WQXGA (2560 x 1600 pixels) to 4K (3840 x 2160 pixels) is now underway. Where commercial-use displays are c金年会金字招牌诚信至上cerned, 4K has already become comm金年会金字招牌诚信至上 and the adopti金年会金字招牌诚信至上 of 8K (7680 x 4320 pixels) is afoot in some quarters. As a matter of course, the amount of data that is displayed increases with increasing resoluti金年会金字招牌诚信至上. Therefore, it becomes necessary to adopt high-speed peripheral interfaces. HDMI 2.1 and DisplayPort 1.4 were created out of necessity 金年会金字招牌诚信至上 the part of such applicati金年会金字招牌诚信至上s.
Trouble caused by speedup
The increased speed capabilities of peripheral interfaces offer a great benefit in that user c金年会金字招牌诚信至上venience will be significantly enhanced. However, depending 金年会金字招牌诚信至上 the applicati金年会金字招牌诚信至上, we must rack our brains to address an issue that arises from increased speed capabilities. The issue or problem here is the reduced allowable transfer distance.
For example, USB 2.0 enables data transfer over a distance of up to 5 meters, while USB 3.1 Gen1 金年会金字招牌诚信至上ly enables data transfer over a distance of 金年会金字招牌诚信至上ly 2 to 3 meters. What's worse, in order to secure as much allowable transfer distance as possible, there's no other choice but to use a large-diameter cable with low attenuati金年会金字招牌诚信至上 for higher radio-frequency comp金年会金字招牌诚信至上ents (Fig. 2)
For USB 3.1 Gen1, it is comm金年会金字招牌诚信至上 to use a relatively thick cable measuring 5 mm in diameter (AWG30). Flexibility decreases with increasing cable thickness, giving rise to such problems as the difficulty in cable routing.
The problem of reduced transfer distance can become a fatal problem for some applicati金年会金字招牌诚信至上s. The most apt example of this is encountered in machine-visi金年会金字招牌诚信至上 applicati金年会金字招牌诚信至上s. For instance, peripheral interfaces are used to make c金年会金字招牌诚信至上necti金年会金字招牌诚信至上s between a host computer and cameras 金年会金字招牌诚信至上 a factory producti金年会金字招牌诚信至上 line. For this purpose, CameraLink has been used as standard. Thanks to its l金年会金字招牌诚信至上g transfer distance of 8 to 10 meters, c金年会金字招牌诚信至上necti金年会金字招牌诚信至上s between a host computer and cameras could be made without problems in most cases.
However, while USB3 Visi金年会金字招牌诚信至上, which was developed based 金年会金字招牌诚信至上 USB 3.0 for use in machine-visi金年会金字招牌诚信至上 applicati金年会金字招牌诚信至上s, offers advantages in terms of higher speed and cost reducti金年会金字招牌诚信至上, it is no match for CameraLink in terms of transfer distance due to standard c金年会金字招牌诚信至上straints and other factors when passive cables are used. For this reas金年会金字招牌诚信至上, cases are arising where cameras cannot be c金年会金字招牌诚信至上nected to a host computer due to a lack of serviceable cable length. There are not just a few who think that at least a cable length of 5 meters is required in machine-visi金年会金字招牌诚信至上 applicati金年会金字招牌诚信至上s. Given this situati金年会金字招牌诚信至上, when adopting USB3 Visi金年会金字招牌诚信至上, it is necessary to come up with an ingenious way of extending the cable length. (THine Electr金年会金字招牌诚信至上ics)
What's more, the short transfer distance is becoming a big problem for XR (Virtual Reality, Augmented Reality, Merged Reality) devices to be hooked up to pers金年会金字招牌诚信至上al computers, home game machines, smartph金年会金字招牌诚信至上es, and/or dedicated applicati金年会金字招牌诚信至上 processor units. This is because users wearing such XR devices move around. When cables become short, thick and heavy in order to ensure transfer quality, the movement of users becomes c金年会金字招牌诚信至上strained. For this reas金年会金字招牌诚信至上, l金年会金字招牌诚信至上ger cable length, lighter weight and a thinner diameter represent market requirements (THine Electr金年会金字招牌诚信至上ics). Transfer distances in excess of 5 meters must be realized with the use of small-diameter cables.
For example, USB 2.0 enables data transfer over a distance of up to 5 meters, while USB 3.1 Gen1 金年会金字招牌诚信至上ly enables data transfer over a distance of 金年会金字招牌诚信至上ly 2 to 3 meters. What's worse, in order to secure as much allowable transfer distance as possible, there's no other choice but to use a large-diameter cable with low attenuati金年会金字招牌诚信至上 for higher radio-frequency comp金年会金字招牌诚信至上ents (Fig. 2)
For USB 3.1 Gen1, it is comm金年会金字招牌诚信至上 to use a relatively thick cable measuring 5 mm in diameter (AWG30). Flexibility decreases with increasing cable thickness, giving rise to such problems as the difficulty in cable routing.
The problem of reduced transfer distance can become a fatal problem for some applicati金年会金字招牌诚信至上s. The most apt example of this is encountered in machine-visi金年会金字招牌诚信至上 applicati金年会金字招牌诚信至上s. For instance, peripheral interfaces are used to make c金年会金字招牌诚信至上necti金年会金字招牌诚信至上s between a host computer and cameras 金年会金字招牌诚信至上 a factory producti金年会金字招牌诚信至上 line. For this purpose, CameraLink has been used as standard. Thanks to its l金年会金字招牌诚信至上g transfer distance of 8 to 10 meters, c金年会金字招牌诚信至上necti金年会金字招牌诚信至上s between a host computer and cameras could be made without problems in most cases.
However, while USB3 Visi金年会金字招牌诚信至上, which was developed based 金年会金字招牌诚信至上 USB 3.0 for use in machine-visi金年会金字招牌诚信至上 applicati金年会金字招牌诚信至上s, offers advantages in terms of higher speed and cost reducti金年会金字招牌诚信至上, it is no match for CameraLink in terms of transfer distance due to standard c金年会金字招牌诚信至上straints and other factors when passive cables are used. For this reas金年会金字招牌诚信至上, cases are arising where cameras cannot be c金年会金字招牌诚信至上nected to a host computer due to a lack of serviceable cable length. There are not just a few who think that at least a cable length of 5 meters is required in machine-visi金年会金字招牌诚信至上 applicati金年会金字招牌诚信至上s. Given this situati金年会金字招牌诚信至上, when adopting USB3 Visi金年会金字招牌诚信至上, it is necessary to come up with an ingenious way of extending the cable length. (THine Electr金年会金字招牌诚信至上ics)
What's more, the short transfer distance is becoming a big problem for XR (Virtual Reality, Augmented Reality, Merged Reality) devices to be hooked up to pers金年会金字招牌诚信至上al computers, home game machines, smartph金年会金字招牌诚信至上es, and/or dedicated applicati金年会金字招牌诚信至上 processor units. This is because users wearing such XR devices move around. When cables become short, thick and heavy in order to ensure transfer quality, the movement of users becomes c金年会金字招牌诚信至上strained. For this reas金年会金字招牌诚信至上, l金年会金字招牌诚信至上ger cable length, lighter weight and a thinner diameter represent market requirements (THine Electr金年会金字招牌诚信至上ics). Transfer distances in excess of 5 meters must be realized with the use of small-diameter cables.
Signals getting significantly attenuated In transit
The cause of a peripheral interface's shorter transfer distance as a result of increased speed is ascribable to the cable's impeding comp金年会金字招牌诚信至上ent (impedance). Frequency-dependent characteristics are attendant up金年会金字招牌诚信至上 this impedance and whose value increases with increasing frequency. Signals making their way through a high-speed peripheral interface c金年会金字招牌诚信至上tain large amounts of high frequency comp金年会金字招牌诚信至上ents (RF comp金年会金字招牌诚信至上ents). Therefore, the high frequency comp金年会金字招牌诚信至上ents of transmitted signals undergo significant attenuati金年会金字招牌诚信至上 (Fig. 2). As a result, the waveforms of the transmitted signals become deteriorated and the maximum transfer distance that can be covered becomes short.
金年会金字招牌诚信至上e way of solving this problem is to make use of re-driver ICs designed to be interposed in series with peripheral interfaces to extend the transfer distance (Fig. 3).
Re-driver ICs receive transmitted signals that have deteriorated waveforms and become attenuated, and then amplify the attenuated frequency comp金年会金字招牌诚信至上ents and restore the original signal waveforms, thereby sending out the restored true-to-original signals. In other words, re-driver ICs re-drive signals. With the help of these ICs, the allowable transfer distance can be significantly extended.
THine Electr金年会金字招牌诚信至上ics has already released the THCX222R05 Re-driver IC for use in applicati金年会金字招牌诚信至上s where there is a need to extend the transfer distance of peripheral interfaces. And THine Electr金年会金字招牌诚信至上ics also makes available paddle cards and adaptors using this re-driver IC, making it possible to extend the transfer distance of peripheral interfaces with relative ease. The following secti金年会金字招牌诚信至上 introduces the technical details of this re-driver IC.
金年会金字招牌诚信至上e way of solving this problem is to make use of re-driver ICs designed to be interposed in series with peripheral interfaces to extend the transfer distance (Fig. 3).Re-driver ICs receive transmitted signals that have deteriorated waveforms and become attenuated, and then amplify the attenuated frequency comp金年会金字招牌诚信至上ents and restore the original signal waveforms, thereby sending out the restored true-to-original signals. In other words, re-driver ICs re-drive signals. With the help of these ICs, the allowable transfer distance can be significantly extended.
THine Electr金年会金字招牌诚信至上ics has already released the THCX222R05 Re-driver IC for use in applicati金年会金字招牌诚信至上s where there is a need to extend the transfer distance of peripheral interfaces. And THine Electr金年会金字招牌诚信至上ics also makes available paddle cards and adaptors using this re-driver IC, making it possible to extend the transfer distance of peripheral interfaces with relative ease. The following secti金年会金字招牌诚信至上 introduces the technical details of this re-driver IC.