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Showing posts with label System. Show all posts
Showing posts with label System. Show all posts

Monday, January 26, 2009



Devices that are able to recognize human's speech and identify it are not particularly new. In fact, they are very common. Some mobile phones have voice control features, so do automatic teller machines and recently we have found out a new voice controlled remote control for home media center. The last one is very interesting and we will come back to it later. However most of them are quite simple. Usually they have a number of words preinstalled, which correspond for example to its menu and they have to ask user on every step of the navigation or whatever the voice recognizing software does. To make things better, European researches have come up with idea of easing up the whole process, making it faster. In turn, voice recognition becomes more complicated from the inside. Nevertheless it didn't stop them trying.

For about three years already there is a project going on under the name of "LUNA Project" developing spoken language understanding in multilingual communication systems. They have come up with a lot of different stuff during these years. The one thing that will be borrowed for the recent study is the SLU - the Spoken Language Understanding system. Unlike the majority of voice recognition systems, this one will not have to ask for an action to do at every particular moment while surfing the menu. SLU provides recognition of every word said, and then filtering it. All the interjections like "hmmm", "oh", etc. will be thrown away, the rest of the words will be analyzed and configured into a command for the device. Such a way user can instantly access needed submenu without getting acquainted with all the peculiarities gadget might have. This is actually the same thing that Amulet Remote we have remembered earlier does successfully.

The conclusion is that if Amulet Devices managed to create a usable voice recognition system, no wonder European researchers will not fail. This is now only the matter of time. The best part of the system is that it will be translated in all European Union languages. The final version of it should aid tourists, take orders at fast food restaurants, help with ATM and in fact be useful at any public location out there.

Sunday, January 4, 2009

Paging Systems are wireless communication systems that are designed to send brief messages to a subscriber. It’s a one-way messaging system in which Base Station send messages to all subscribers. The Paging System transmits the message also known as Page, along with Paging System access number, throughout the service area using Base Station, which broadcast the page on a radio link.
Types of Paging Systems

The Paging Systems can be of two types.

* Manual Paging System: In a manual paging system, a message is sent to the paging operator through telephone call by the caller. The message is then delivers to the pager through paging network by the operator.
* Automatic Paging System: In an automatic paging system, the incoming requests are automatically processed by the paging terminal and then this information is delivers to the pager. Automatic Paging Systems are mostly used.

Messages in Paging Systems

One of the following four types of information messages can be delivered in a Paging System.

* Alert Tone Message
* Voice Message
* Digital String Message
* Text String Message

Alert Tone Message: In the alert tone message, a dedicated telephone number is assigned to the receiver, which is also known as Tone Pager. The pager is triggered by dialing the number. To generate tone-type messages, the advantage of tone paging is that it utilizes a small amount of airtime.

Voice Message: In the voice message, a voice message can be transmitted in some tone paging systems after the beep.

Digital String Message: In digital string message, the receiver is a Numeric Pager. The string can be the telephone number of the caller or a coded message. This coded message is generated on request of the caller by the paging center and is decoded by a codebook built into the pager. This type of paging takes less amount of airtime.


Text String Message: In the text string message, the receiver is an Alphanumeric Pager, which has large screen to display the text strings. This type of messaging is becoming more popular than numeric messaging.
Paging System Architecture

The Paging System network consists of six basic elements.

* User Terminal Equipment (Input Devices)
* Paging Terminal
* Operation and Maintenance Center (OMC)
* Base Station Controller (BSC)
* Base Station (BS)
* Pager

User Terminal Equipment (Input Devices): Terminal equipment is used by the caller to send messages. The equipment can be a telephone handset, a computer with modem and a specific input device. A telephone handset is used to generate alert tone or numeric type messages and is delivered through the Public Switch Telephone Network (PSTN), while alphanumeric messages are generated by the computers and are delivered through the Public Switch Digital Network (PSDN).

Paging Terminal: The messages are sent to the paging terminal through user access interface. A paging terminal can supports 1 million pagers and is connected to a central office of PSTN. The paging terminal also maintains a database of the customer which conations information such as page number, pager code etc.

Operation and Maintenance Center (OMC): The OMC is used for operation, administration and maintenance functions of a paging network. The customer’s database which is stored in terminal paging can be accessed by the OMC to add or delete new customer’s records.

Base Station Controller (BSC): The paging terminal and base stations are connected by the BSC by powering up the base stations. In transmitting mode, the BS consumes the high power and when it is in idle mode it consumes low power.

Base Station (BS): The messages to the pager are broadcasted by the BS over radio links. The BS and its pagers have dedicated paging channels. The messages from the paging terminal to the BS are transmitted by using transmission technologies, which are leased telephone lines and satellite based networks.

Pager: A pager includes four basic elements.

* A Receiver: To receive and demodulate the paging signals, the receiver is tuned to the same radio frequency (RF) as the BS.

* A Decoder: The binary information is decoded by the decoder.

* A Control Logic: The control logic provides control for duplicate messages, locking messages and freeze messages.

* A Display: A display is used to read messages.

Paging Systems have ultra-reliable coverage, high infra structure, high complexity and high hardware cost.