Blooming America

AT&T belongs to Bell Labs.

At this time, they are also studying one thing.

-Broadband.

AT&T did not place its hopes on the Iridium Star Program.

In addition, AT&T also has its own plans.

There is what they are doing now-research and development of their own broadband network.

Catherine established a broadband network across the United States.

But AT&T does not have the support of the US government. Although the Pentagon is stupid, they will not invest repeatedly in the same thing. So AT&T only

Can choose to use their existing technology to break through the locks of the network.

The power of the Internet has been noticed by many people, and the benefits contained in this powerful thing have also been noticed by AT&T.

They cannot ignore this market.

And in a sense, they have an advantage over Catherine.

Optical fiber requires dedicated broadband, but AT&T's plan is to use their existing telephone lines to access the Internet.

Catherine is indeed aggressive, but AT&T is not completely defensive.

In fact, as long as they want to do it, their advantage is even greater than Catherine.

For AT&T, for a long time, the telephones of communication users have been connected to the city exchange through the "twisted copper wire" subscriber line, and entered the communication network of the public exchange.

(PSTN), connected to the phone of the other user, so that both parties can talk to each other.

Twisted copper wire provides a frequency band of 300～3400Hz for traditional analog telephones. In order to adapt to the low-speed data communication used by telephone users, AT&T tried to install a modem to make the rate 33k.

s and up to 56k

The data signal of s can perform data communication with the other party through the analog voice band. This is the beginning of their strategy.

Although twisted-pair copper wires do not have any bandwidth limitations-they can't reach that level-but the switches in the communication network are limited. They only allocate a voice band for telephone communication. Although the user's data information is transmitted through the modem, the switch does not recognize it as a data signal from the modem, but treats it as a voice signal.

At the same time, at this time, AT&T also encountered the historical predicament of the Internet.

It is the "last mile" one by one.

The original meaning of this word refers to the completion of the last leg of a long journey. It is extended to be the last and critical step when completing a thing (it usually means that this step is full of difficulties). The communication industry often uses the "last mile" to refer to the connection from the communication service provider's computer room switch to the user's computer and other terminal equipment. The users involved in the “last mile” refer to users who are in the position of network terminals such as households and individual users or small business users, rather than large commercial users or professional communication companies. Therefore, the line between the service provider and the user is not It will be the single-mode fiber commonly used in the Boneqian network. The "last mile" also involves the problem of wiring at the location where the user's computer and other terminal equipment are located. Since each user's room is different, communication service providers, real estate developers and users need to consider three aspects based on actual conditions. How to connect user equipment to the network, how to migrate to other locations, and how to log out of user services.

This creates a problem.

So what AT&T is thinking about is a transmission mode similar to ADSL, which is part of the "digitalization" that Catherine is talking about.

In fact, simply relying on the low frequency part of the copper wire used in the traditional telephone line system, their practical use of this technology is completely no problem, but in that case, AT&T found that if it did so, the transmission speed of the system It's just barely compelling.

The technology they are using now is to use DMT (Discrete Multi-tone) technology to convert the original telephone line 40KH frequency band to 256 sub-bands with a bandwidth of 4.3125KHz. Among them, the frequency band below 4KHz is used to transmit TS (traditional telephone service), the frequency band from 20KHz to 138KHz is used to transmit uplink signals, and the frequency band of 138KH is used to transmit downlink signals. DMT technology can adjust the number of bits modulated on each channel according to the condition of the line in order to make full use of the line. Generally speaking, the greater the signal-to-noise ratio of a sub-channel, the more bits are modulated on the channel. If a sub-channel has a poor signal-to-noise ratio, it is discarded. At present, ADSL can reach up to 40K

ps, downlink 8M

ps data transfer rate.

In other words, theoretically speaking, it can provide up to 3.5M without affecting normal telephone communication.

ps uplink speed and up to 24M

ps downlink speed.

In other words, the download speed is up to 3MB

S.

Although it is a theoretical speed, this speed can already knock Catherine's broadband down.

Through such DMT technology, AT&T can make subscriber lines avoid narrowband voice switches and become "digital subscriber lines."

AT&T calls it tal-Su

i

e

-ne, which is DSL.

DSL technology supports symmetric and asymmetric transmission modes on subscriber lines of traditional telephone networks, and solves the "last mile" transmission bottleneck problem that occurs between network service providers and end users. Since a large number of telephone subscriber loops have been laid, how to make full use of the existing steel cable resources and achieve high-speed access through copper twisted pair has become AT&T's next research focus.

But in time, their technology will definitely be practical. At that time Catherine was nothing.

This conclusion is an encouraging news for AT&T.

...Just as AT&T was happily conducting research, Catherine had already arrived at the Thunder Lab.

Now in this world, the only thing that can be compared with Bell Labs is Thunder Labs.

But Catherine was not preaching about her plan at this time.

In fact, at this time, Catherine was watching the new plan prepared by Thunder Lab with interest here.

-They are preparing to develop a mechanical UPS power supply.

UPS (nte

le-we

-System), that is, uninterruptible power supply.

This is a constant voltage and constant frequency uninterruptible power supply with an energy storage device and an inverter as the main component. Mainly used to provide uninterrupted power supply to a single computer, computer network system or other power electronic equipment. When the mains input is normal, the UPS will stabilize the mains and supply it to the load. At this time, the UPS is an AC mains voltage stabilizer, and it also charges the battery inside the machine; when the mains is interrupted (accidental power failure) Immediately, UPS will continue to supply 110V AC power to the negative trimmer by means of inverter conversion from the power of the battery in the machine, so that the load can maintain normal operation and protect the software and hardware of the load from damage.

Generally speaking, the supercomputer center needs UPS power supply, so that it can effectively protect the security of the data.

In the North American Computer Center, a series of UPS power supplies are installed. These storage-type UPS power supplies produced by GM are the core there.

These UPSs can ensure that in the event of a sudden power failure, they can start the generator in time and keep the supercomputer running normally.

But this kind of power storage UPS is not perfect.

So at this time, Xunlei Lab is thinking about a solution that can solve the problem perfectly.

Here are their conclusions-mechanical batteries.

That is, the flywheel battery.

Before the era of using batteries, uninterruptible power supplies used flywheels and internal combustion engines to provide electrical energy to loads. This uninterruptible power supply is called flywheel or rotary uninterruptible power supplies. The flywheel uninterruptible power supply consists of a rectifier, a DC motor, a flywheel, a diesel engine (or gasoline engine), and a generator. In the case of power supply from the grid, the direct current provided by the rectifier drives the motor to drive the flywheel to rotate, and a generator to supply power to the load. Due to the inertia of the flywheel, the generator speed can be kept balanced, and the uninterruptible power supply plays a role in filtering the disturbance of the power grid. When the power grid is cut off, the flywheel continues to drive the rotor of the generator to rotate, and at the same time the diesel engine is started to drive the generator to generate electricity, replacing the original grid to supply power to the load.

And now, this kind of flywheel battery has been brought out again.

This is the new plan of Xunlei Lab...According to the design of Xunlei Lab, there is a motor in the flywheel battery. When charging, the motor runs in the form of a motor. Driven by an external power source, the motor drives the flywheel to rotate at a high speed. The "charging" of the flywheel battery increases the speed of the flywheel to increase its function; when discharging, the motor runs as a generator, and the flywheel drives the output of electrical energy ~ www.wuxiaspot.com ~ completes the mechanical energy (kinetic energy) to electrical energy Conversion.

When the flywheel battery emits electricity, the speed of the flywheel gradually decreases. The flywheel of the flywheel battery runs in a vacuum environment and the speed is extremely high. "The bearings used are non-contact magnetic bearings. In this way, friction can be effectively reduced." The technician really told her.

(Does this product use the legendary magnetic levitation?) Catherine murmured in her heart.

Catherine had also heard of the flywheel battery, but Catherine hadn't used it much.

In fact, Catherine had very little contact with UPS.

But this does not affect Catherine's optimistic view of the prospects of this industry. Even if you use it yourself, this is enough.

So Catherine was very satisfied with this plan. "You can rest assured to do it well, I support!"

She said so.

"It was said that it was not technical enough...

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