Tuesday, January 22, 2008

Cordless telephone systems

Cordless telephone systems are full duplex communication systems that use radio to connect to a portable handset to a dedicated base station, which is connected to a dedicated telephone line with a specific telephone number on the public switched telephone network. In the first generation cordless telephone systems, the portable unit communicates only to the dedicated base unit and only over a distance of few tens of meters. Early cordless telephones operate solely as extension telephones to a transceiver connected to a subscriber line on the PSTN and are primarily for in-home use.

Second generation cordless telephones have recently been introduced which allow subscribers to use their handsets at many outdoor locations within urban centers such as London. Modern cordless telephones are sometimes combined with paging receivers so that a subscriber may first be paged and then respond to the page using the cordless phone. This system provides the user with limited range and mobility, as it is difficult to maintain a call if the user travels outside the area covered by the base station.

Friday, January 18, 2008

Paging Systems

Paging systems are communication systems that send brief messages to a subscriber. Depending on the type of service, the message may be numeric message, an alpha numeric message or a voice message. Paging systems are typically used to notify a subscriber of the need to call a particular telephone number or travel to a known location to receive further instructions. In modern paging systems, news headlines, stock quotations and faxes may be sent. A message is sent to a paging subscriber via paging system access number with a telephone keypad or modem. The issued message is called page. The paging transmits page throughout the service area using base stations which broadcast the page on a radio center.

Paging systems vary widely in their complexity and coverage area. While simple paging systems may cover a limited range of 2 to 5 kilometers or may even be confined to individual buildings, wide area paging systems can provide worldwide coverage. Though paging receivers are simple and inexpensive, the transmission system required is quite sophisticated. Wide area paging systems consist of a network of telephone lines and many base station transmitters, large radio towers that simultaneously broadcast a page from each base station. Simulcast transmitters may be located within the same service area or in in different cities or countries. Paging systems are designed to provide reliable communication to subscribers wherever they are; whether inside a building, driving on a highway, or flying in airplane.

Wednesday, January 16, 2008

Project overview

This project aims at comparing different packet scheduling methods that are used now and finding out the best algorithm that can be used for a wireless networks. In the algorithms which we consider, the schedulers are allotted a flow and have to transmit their packets during each flow, using the resources allocated to them. In the normal algorithms, when a flow encounters an error, the scheduler is then allocated a larger resource at a later time so that the flow can be compensated. On the other hand, the Opportunity Based Scheduler is based on the premise that fairness should be ensured in the opportunity given to the flows in the use of resource and not the actual benefit received by the flows from the use of the resource. This strategy emphasizes the schedulers to use the resources more efficiently. In this project we are comparing three algorithms namely Weighted Round Robin, Deficit Round Robin and Opportunity Based Deficit Round Robin. The algorithms are compared based on the throughput values. Finally, we prove that ODRR algorithm is the best among all the three algorithms. The ODRR scheduler is versatile enough for use in allocating resources other than bandwidth and can be used in different contexts such as in ATM, Internet Backbone networks carrying IP packets.

Monday, January 14, 2008

Charactersitics of Gunn diode

Initial adjustments :

· Pin bias is kept at maximum

· Gunn bias is between 6 and 7

· Adjust the starting screw gauge for square wave output at the detector

· Have minimum attenuation

· Vary slotted line plunger to obtain maximum amplitude for square wave.

· Keep beam voltage to be between 270 and 300.

· Keep repeller voltage to be maximum and then reduce it to get perfect square wave

· Adjust the amplitude and frequency to get maximum amplitude of square wave

· Keep the probe end at the detector and do these adjustments

· Make initial adjustments.

· Provide maximum attenuation.

· Vary the Gunn bias in steps of 0.5 and note down the current.

· Change the V-C knob correspondingly to note down the voltage and current

Sunday, January 13, 2008


Our next destination was Amritsar. It had two important places, one of them is the golden temple. It was just amazing and the entire place was full of energetic vibrations which charges up your mind and soul. Anyone who wishes to enter temple must wear a turban. Ladies should wear some clothing that covers their heads. Inside the golden temple there is a small pond which has pure water and lot of fishes in it. The buildings that are surrounding the golden temple is the resting place of many Sikh gurus. Actually in 1574, Guru Ram Das made his home by the side of this pool which had several healing powers. The place where Guru lived is known as Guru-Ka-Mahal. The golden temple is chiefly constructed by the efforts of Ranjith Singh. He took special care in the gold platings and Maharaj also made a grant of Rs. 5 Lakh for this purpose.

Tuesday, January 8, 2008

Some more beautiful Pictures

We visited only limited places like Indira Gandhi memorial, lotus temple, Qutub minar, India Gate, etc in Delhi. We planned to visit the other places like Red fort, Parliament and theen Murthi Bhavan on our return journey. Most of the places were a treat to watch, especially I was impressed by the architectural style of the lotus temple. Mostly our bus traveled through the locality of high profile people, which should be properly maintained. So I'm unable to comment about the maintenance and other facilities available for the general public in Delhi. The Delhi trip was over by the night fall and we returned to our restaurants to take rest after a tiresome day which marked our tour's beginning.

Sunday, January 6, 2008

AI RoboForm

AI RoboForm is a push-button web form filler with some serious
Artificial Intelligence (AI) inside. It allows you to define your
personal profile or "usual" responses to a web form.

This information is then saved, and when you need to fill a form,
just click "Fill Forms" button, and form is filled out.

AI RoboForm is fully client-based, so it is very fast, it never
disables web site functions, and it works even in pop-up HTML

The most important feature of AI RoboForm is high accuracy - it
fills 95% of all fields correctly. (Pro version with advanced
features and commercial license available for 29.95).


· AutoSave passwords in browser.
· AutoFill passwords to login form.
· Click Login button for you.
· Fill personal info into online forms.
· Save offline passwords & notes.
· Generate Secure Random Passwords.
· Encrypt passwords and personal info using 3-DES.
· All personal info is stored on your computer only.
· Put passwords on USB KeyChain for extra security.
· Sync your passwords and safenotes to a Palm.
· Backup & Restore, Print your passwords.

Whats new in v6.9.88?

* Fix crash in IE caused by Windows problems
* Fix Import Outlook Contacts on Vista.
* Do not show Registration dialog to new users.
* Do not offer to import passwords from IE on install.
* Fix attachment of RF toolbar to Firefox when called by View->
Toolbars-> Roboform Toolbar.
* Improve event listeners for Firefox.

Saturday, January 5, 2008

India Gate

It was already night time and the sight was awesome. India gate was lit with by the flood lights and flooded by the visitors. I do not know much about this place. This has Amar Jyothi, which pays homage for the martyrs of the war. There are three flags and a pistol with helmet turned upside down, as a sign of honor to the soldiers. There is also flame that glows all day long and most the national and inter-national leaders pay homage to the soldiers here, on any important occasions. There are also several places like Rastrapathi Bhavan, Parliament, Red fort, etc. I've taken photos of only a few of them, hence I won't be publishing them. They are also one of the places of highest security in all over the country. Pkaces like Theen - Murthy Bhavan, Gandhi Jayanthi, etc attract tourists.

Lotus Temple

Lotus temple- reminds you a lot about Sydney. But it is as beautiful as that in Indian style. The specialty of this place is that it is religion free. People of any religion can come in and offer their prayers. The prayer hall is really huge with seating capacity of nearly 400 - 500. Either side of its entrance is decorated with flowers. They look attractive. On reaching that temple, the volunteers will give a briefing about that and will allow you enter that temple. Its just a big hall with no photos or statues of any gods. You have maintain absolute silence and pray for any duration of time. You can feel the positive energy that is vibrating inside hall and you know that your prayers will be answered. Good God!!

Qutub Minar

The Qutub Minar is 72.5 metres high (237.8 ft) with 399 steps leading to the top. The tower is now unfortunately once again closed to visitors. The diameter of the base is 14.3 metres wide while the top floor measures 2.75 metres in diameter.

Surrounding the buildings are many fine examples of Indian artwork from the time it was built in 1193. A second tower was in construction and planned to be taller than the Qutub Minar itself. Its construction ended when it was about forty feet tall.

It is evident from the Indian History and has been accepted by the ASI that the place where Qutub Minar stands today was once occupied by about 20 Jain temples. These were demolished and the stones reused to build the present complex. An inscription stating this has been put by ASI some 10 meters from the base of the minaret. Jain trithankar figurines can be found on many pillars and walls of the complex. That was really a joy to watch. The time was evening with cool breeze blowing across your face and the mammoth pillar infront of your eyes, its just a sight to behold.

Delhi - My first destination

Hi. As I've promised, I'm uploading my tour photos one by one. The place which I visited first is the national capital Delhi. It had several beautiful places. One of the finest is Indira Gandhi Memorial. This is the place where she was shot dead by her own guards. The entire house was converted to a museum that depicts various awards and accords that she received. It includes british royal medals, letters from Mahatma Gandhi himself, a diamond studded sword, etc. The house also had pictures and fond memories of late Rajiv Gandhi. It shows the computer used by Rajiv, his dresses, several electronics components assembled by him, letters written by him to Ms.Indira, etc. There is also a great library which has the books read by Gandhi family. Nation has lost several great leaders, you will definitely feel that when you leave this place. Let's hope it doesn't happen again.

Numerical aperture

· One end of the cable is connected at Tx2 and the other end is connected in the NA unit.

· No other connections.

· In the NA unit for various heights note down the vertical and horizontal diameter of the light.

PC to PC communication:

· Startàprogramsàaccessoriesàcommunicationsàhyper terminalà hyper terminal (2)

· Give some name and OK

· Connect using : COM2

· Connect BUFINàCOM1


· Detector to laser

· TTL out to COM2

· Then type the data.

File transfer:

Sending: transferàsend fileàbrowse and choose a fileàhave Kermit protocolàsend

Receiving: transferàreceive fileàbrowse to select location to store the fileà have Kermit protocolàreceive