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Presentation on the topic "Cellular communication" can be downloaded absolutely free on our website. Project subject: Physics. Colorful slides and illustrations will help you interest your classmates or audience. Use the player to view the contents, or if you want to download the report - click on the appropriate text below the player. The presentation contains 39 slides (s).
Slides presentation
Slide 1.
Municipal general educational institution "Secondary school №9 them. KK Rokossovsky "
Creative project on physics on the topic "Cellular communication"
The project performed: Lebedev Anton, study 9A class
Project Manager: Ovcharov Viktor Ivanovich, physics teacher
zheleznogorsk 2012
Slide 2.
The goal of the work is: to collect information from various sources to learn the history of cellular development, the principle of working phones, the reasons for the impact of cellular communication on the human body.
Objectives: 1. Examine the opening history of electromagnetic waves, cellular generation standards. 2. Appointment of base stations, the device and the principle of the phone in the cellular network. 3. The harmful effect on the human body and the radiation rate of the cell phone. 4. Develop recommendations on the use of cell phones. 5. Questioning learning schools.
Slide 3.
Heinrich Hertz
Gulielmo Marconi.
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In July 1947, BELL LABORATORIES Employees Shockley, J. Bardin and W. Brattine invented the transistor.
The idea of \u200b\u200bD. Ring - base stations with their coating zones form cells, the size of which is determined by the territorial density of the subscribers of the network. The frequency channels used to work one of the base stations of the network can be used by other base stations of this network.
Slide 7.
Martin Cooper
Taking the Motorola Dina-Tac in his hands, Martin Cooper went outside and made the world's first cell phone call.
Slide 8.
Cellular communication of the first generation (1G).
Standard CDMA, TDMA, IDEN, PDS, PHS Data in such networks could be transmitted only at low speeds up to 2.4 kbps, and the spectrum is limited to a frequency of 900 MHz.
Slide 9.
Second generation cell (2G).
GSM standard The main difference of second generation systems is that they are "digital", i.e. The voice is transmitted in digital form.
Slide 10.
Cellular communication of the third generation (3G).
Systems operate at the following data transfer rates: for subscribers with high mobility (up to 120 km / h) - at least 144 kbps, for low mobility subscribers (up to 3 km / h) - 384 kbps, for fixed objects on short distances - 2,048 Mbps.
Slide 11.
Basic stations.
The base station (in relation to cellular communication) is a radio transmitting equipment complex (repeaters, receiving transmitters), communicating with the final subscriber device - a cell phone.
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1. Picture manipulator button 2. Call reception button 3. Phonebook 4. Keyboard 5. Antenna 6. Sound speaker 7. LCD display 8. Turning on-off key and call reset 9. Cancel key 10. Microphone (located below)
Exterior Mobile Phone
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The cell phone is characterized by the fact that it causes our body a "triple blow." Here, there are three sources of radiation of microwave fields in one apparatus and generating various EMFs in various modes of its operation. 1. The first of them is an antenna of a cell phone, emitting EMF, the power of which is determined by Watt units. 2. This radiation is carried out in transmission mode, moreover, a significant part of AM, partially relaxing by the cranial box, penetrates our brain. In standby mode, the cell phone is similar to other electronic devices and radiates weak fields of non-coordinated intensity, which, accumulating in the body, can lead to negative consequences. 3. In the reception mode, the microwave radiation through the auditory passage penetrate directly into the brain.
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As a result of numerous studies in the field of biological effects of electromagnetic emissions, it was established: 1. that they have a property with time to accumulate in the human body, disrupting its bioenergy equilibrium and, first of all, the structure of the so-called. Energy information exchange (ENIO), which ensures the normal functioning of information and exchange processes between all organs and systems, at all levels of the organization of the human body, including those between the organism and the external environment. 2. The most sensitive systems of the human body are: nervous, immune, endocrine and reproductive (sex). 3. The Biological Effect of EMF in conditions of long, many years of exposure, can lead to the development of remote consequences, including the degenerative processes of the central nervous system, blood cancer (leukemia), brain tumors, hormonal diseases, etc. 4. A special danger of EMF is represented for children and pregnant women. Women, since the non-formed children's body has increased sensitivity to the effects of such fields. 5. Very sensitive EMP are also people with diseases of the central nervous, hormonal, cardiovascular system, allergies and people with weakened immunity.
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Children slow down ... Alan Sup, head of the branch of biophysics of the Bristol Oncology Center, half an hour has given phones to the guys 10-11 years old. At half, they worked in the conversation mode, others have been disabled. And then the scientist conducted neurophysiological tests. For those who have included the included mobile phones, all reactions turned out to be slowed down. Another experiment showed that even after a two-minute conversation in adolescents, the bioelectric activity of the brain is changing 11-3 years old. It comes to normal only after two hours. What does it mean? The child is changing the mood, it perceives the material worse in the lesson, if during a change it was chatted via cellular.
Slide 24.
And in adults, the blood of the Hungarian Biologist of the Turkue boils 76 volunteers to make two calls, 7, 5 minutes each. The body trembled by all the fibers: the brain biotoks have changed, the brain circulation has slowed down, blood pressure dropped. Doctors have recorded anxiety and stress. And the Russian professor Igor Belyaev, working at the University of Stockholm, included the phone next to test tubes with human blood. An hour later, blood in several of them "Zakipel"! "No, she did not heat up," the researcher explains. - But blood cells, lymphocytes, behaved, as if a person had a very strong heat - 44 degrees. " The effect of "heat shock" remained 72 hours.
Slide 25.
Embryos die ... In the Moscow Institute of Biophysics, Professor Yuri Grigoriev made two incubators. In each put 63 chicken eggs. Over one "bird house" at an altitude of 10 cm brought a mobile phone of the GSM standard. The phone worked in this mode: 1, 5 minutes turned on, half a minute turned off. Embryonic development disorders began on the third day. Only 16 birds hatched, which "listened" to the phone! But they also turned out to be non-visual. For comparison: in the incubator, where the eggs did not dismiss calls, 51 chicks appeared without any problems.
scientists from Moscow State University discovered that yeast fungi and acetic acid bacteria came from the mobile phone. This means that the device on the belt or in his pocket is next to the intestines - can spoil life to someone from 500 microorganisms living there! And they will distort the careless owner.
Slide 26.
SAR - SPECIFIC ABSORBTION RATE - a unit of measurement showing the maximum specific power absorbed by the human body (W / kg) with a normal conversation on a cell phone.
Maximum safe level - 2.0, most modern phones have SAR from 0.5 to 1.0.
Slide 27.
At what age did you start using a cell phone? What time is you talking about a cell phone a day? What is your phone model now? Where do you usually store a cell phone? Where is your cell phone at night? Do you know a cell phone device? Do you know about the harmful effects of cell phones on the human body?
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SAR level measurement results - the safest you are given the opportunity to get acquainted with the list of mobile phones that have the smallest level of SAR radiation. All data is given for phones operating in the GSM 900 standard. The table shows the SAR values \u200b\u200bdefined for 10 g. Fabric. Remember: the smaller the value of SAR, the lower impact has a mobile phone on a person! Read more about SAR model Sar Magcom Magcom 0.04 Motorola Startac 130? 0.07 Samsung SGH-F700V QBOWL 0.07 Motorola V100 0.09 Samsung SGH-Z560 0.10 Swisscom XPA V1615 0.12 Motorola MPX200 0.12 Philips 362 0.12 Telefoon Totaal Basicphone 0.12 Mitac Mio A501 0, 12 Samsung SGH-X830 0.12 LG S5200 0.12 Audiovox XV6600 0.12 LG KG320S 0,13 Sagem MyMobiletv2 0,13 Motorola V101 0.14 SonyERICSSON T292A 0.15 Nokia 8810 0.15 E-TEN M500 0.16 Vodafone VPA IV 0.17 BlackBerry 7280 0.17 Samsung GT-i8000 Omnia II 0.17 T-Mobile MDA Pro 0,17 BlackBerry 6280 0.18 Samsung SGH-S105 0,18
Slide 35.
7. Do you know about the harmful effects of cell phones on the human body?
Slide 36.
REMEMBER! The conversation limit is 15 minutes a day (children from 8 to 14 years old), adults - 30 minutes. Maximize the period between two conversations (the minimum recommended - 15 min), doctors do not recommend using "mobile phones" to children under 8 years old. Do not carry the included phone in breast pockets (the risk of developing malignant tumors). Mobile phone must be at a distance of at least 2 cm from the human body in a special case. During the conversation, it is advisable to use the headset and the "Hands" system ("Hands Free"). Do not acquire former mobile phones. If possible, enjoy loud connections. Instead of conversation, use SMS services. Do not talk in a car on a cell phone. The metal case of the car acts as "screen", radioculum worsens. In response to this, the mobile apparatus increases its power, which leads to greater irradiation of the subscriber. For accommodation in buildings from reinforced concrete structures, the conversation on the mobile communication device should be conducted near the large window, on the loggia or balcony. During the conversation, hold the device necessarily for the bottom. If you keep the phone in the "fist", the power of the device increases by about 70% and thereby increasing irradiation. Change the position of the tube during the conversation process (left and right).
Slide 37.
Conclusion: The effect of electromagnetic fields on human health is the task of science. A person himself can provide his security if they have the necessary information. Each of us can and is even obliged to take simple precautions. Cell phone is safe only with a reasonable attitude towards it.
Slide 38.
The list of sources used and literature http://teleffon.info/principle.htm http://www.hardline.ru/9/70/1847/ http://ru.wikipedia.org/ http: //www.3dnews. RU / http://cxem.net/sotov/sotov8.php http://www.krugosvet.ru/ A.Gridin, K. Modanov, I. Zubik "Mobile for all. Device and working mobile phones »Maryarevsky A., Olevskaya N. Your mobile phone (popular tutorial). M, "Peter", 2004 Zakirov Z.G., Nadezhov A.F., Faizullin R.R. Cellular communication of the GSM standard. Modern condition, transition to third-generation networks ("MTS Library"). M., "Eco-Trendz", 2004 Popov V.I. Basics of the cellular communication of the GSM standard (Engineering Encyclopedia TEK). M., "Eco-Trendz", 2005
Within the age of one and a half years, the telephone connection, the telephone connection was so firmly in the life of a modern person, that the lack of a phone in the apartment almost became an exception. The advantages of wired telephone networks should include the reliability of the communication and the developed system of subscriber networks, allowing the user to contact the subscriber in almost any country of the world.
However, the "tough binding" of the subscriber to the stationary telephone device, "limited", and the length of the wire tube, did not allow the user to be mobile, i.e., freely move in space during conversations or between them.
In the second half of the last century, as technology and technology improves, the idea of \u200b\u200bcreating a world (global) network has become developed. mobile (cellular) telephone communication, allowing the user to have access to a developed subscriber network with the help of a portable portable (mobile) tube-telephone of significant (tens of kilometers) of the radius of action.
The implementation of this idea would allow telephone connection to a new level of popularity and accessibility from the user's point of view, which would have their own individual phone number and almost unlimited freedom of movement (mobility) during conversations or between them.
The proposed principle of mobile telephone communication is simple enough: with the help of a tube-phone (mobile phone), the subscriber is associated with the nearest base station (transmitter) of the network (Fig. 224).
Fig. 224. Basic cellular station (transmitter)
This base station, in turn, is associated with the following transmitter of the network, etc. As the subscriber's requirements (Fig. 225).
Fig. 225. Cell network of transmitters
The described principle of creating a developed subscriber network is called cell Principle, because on the same principle of the bee arrange honeycombs inside the hive. At the same time, each created cell serves as the basis for creating the next exact same cell and so on.
By virtue of this circumstance, mobile telephone communication is also called also cell phone Communication. When the subscriber moves (for example, by car) (see Fig. 225), the base stations independently follow it and "transmit" to each other, which is happening almost without loss of communication quality, quickly and completely imperceptibly for the user.
The simplest part of the block diagram of the cellular communication is a mobile (portable) phone, consists of two parts: the "tube" or ME (Mobile Equipment) itself and the subscriber identification module, or smart maps SIM (Subscriber Identity Module) obtained when concluding a contract with one or another operator.
Each cell phone in production is assigned its own number or international mobile device identifier ιμε (International Mobile Equipment Identity), which makes it possible to distinguish it from the second exactly the same.
In our country, the GLOBAL SYSTEM FOR Mobile Communications (Global System for Mobile Communications) is used in 1990, this standard uses the operating frequency ν \u003d 900 MHz, which allows to significantly improve the quality of communication compared to the first generation standards.
The first GSM operator accepted subscribers in 1991, and by the beginning of 1994. World networks based on this standard had 1.3 million subscribers. By the end of 1995, their number increased to 10 million!
When you turn on a mobile phone with an activated smart card, it "itself" finds the nearest basic station of the corresponding cellular network, after which the entire telephone service package of this network becomes an affordable subscriber.
Each transmitter provides radiocrying on average up to two tens of kilometers from it (Fig. 226). For the rational use of the cellular network of transmitters, optimal schemes of their interpordability on the ground are developed, taking into account its relief.
Cellular principles ( using light, signals and sound) The beginning of the history of wireless communications
- Many times in history were used to communicate heliographs, flags (semaphore), ... - China, Han Dynasty (206. BC - 24G. AD) Using signal towers; - 150g. BC. flue signals for communication (Polybius, Greece) - 1793, optical telegraph, french engineer K. Shapp
- Start of communication with electromagnetic waves:
James Maxwell (1831-79): Theory of electromagnetic fields, wave equations (1864)
1876 \u200b\u200btelephone Alexander Bella
G. Herz (1857-94) demonstrated a wave type of electrical transmission through space (1888)
On May 7, 1895, the St. Petersburg physicist Alexander Popov did a report in the physicochemical society with a demonstration of the radio excavation created by them for fixing atmospheric oscillations.
On June 2, 1896, Gulielmo Marconi patented radio as its invention (Popov's scientific publications on this account appeared in the same month, but were addressed to a completely different audience).
1896 in London he managed to transfer a message to a distance of 10 kilometers.
1907 Commercial Transatlantic Communications - Huge Basic Stations (with antenna height 30 - 100m)
1915 Speech Transfer New York - San Francisco
In 1896, he demonstrated his experiments to the individual Society of St. Petersburg, having transferring signals using the Morse alphabet inside the University Building.
The beginning of the history of wireless communications concept:
- large area for one transmitter
- Large "mobility" due to high energy intensity
- Low-feature systems prone to interference
- High price
1911 - mobile transmitter on airship
1926 - Train (Hamburg Berlin)
1927 - First Commercial Car Radio (reception only)
The first mobile communication systems began in the 1940s in the United States and in the 50s in Europe.
Development of telecommunications in Russia
Development of telecommunications in Russia Classification of wireless networks
Common use
departmental
dispatcher
Trunking
panzhing
satellite
computer
optical
Development of cellular communication standards Development of cellular communication standards Cellular communication networks
- 1G: Analog networks. Idea: Coverage of the SATE spaces (zones of action of one base station) and the organization of COT clusters. Supported only telephony. Standards: NMT, AMPS.
- 2G: Digital network switches. An access method with a temporary separation of channels is used. There is also a cellular structure. Support telephony and data transmission. For the organization of faster access, GPRS (2G +) can be used. Standards: GSM, D-AMPS, PDC.
- 3G: Digital network switches / packages. A broadband access method with coded channels is used, support multiservice traffic. Standards: CDMA, WCDMA, CDMA2000, I-MODE, etc.
- 4G: Digital network switches. Are in the development stage
Cellular networks 3G.
746-794 MHz, 1.7-1.85 GHz, 2.5-2.7 GHz
Cellular GSM.
- 800-900 MHz.
Cellular GSM.
- 1.85-1.99 Ghz.
Wireless LAN (IEEE 802.11b / g)
- 2.4 Ghz.
Bluetooth
- 2.45 Ghz.
Wireless LAN (IEEE 802.11a)
- 5 Ghz.
Geometric structure of the cellular system Model multiple frequency use
Types of cells
Macrocells (3 to 35 km)
Microcells (0,1 to 1 km)
Picocells (0.01 to 1km)
Nanocells (1m to 10m)
General view of the cellular system
Network Sub-System
An example of a mobile cellular connection Example of a mobile cellular connection Example of a mobile cellular connection Example of a mobile cellular connection Example of a mobile cellular connection Example of a mobile cellular connection Example of a mobile cellular connection
The purpose of the lesson:development of information and communicative competencies of students.
Equipment: Screen, projector, magnets, watman sheets, text sedimers Green and red, black markers, cast-iron saucepan.
DURING THE CLASSES
Teacher: The topic of our lesson is close to you, familiar and very relevant. She is encrypted in these pictures.
Appendix 2. . Slide 1.
|
Guess: cellular.
Appendix 2. . Slide 2. (Stages of development)
The teacher tells or a student makes the message:
Cellular telephone - it's nothing but radiotelephone. The phone was invented in 1876, the radio is also the opening of the last century. It remained only to connect these two technologies, and it took almost 100 years. This became possible after the appearance of integrated chips and relatively lung batteries. This year, the Mobile Phone has a small anniversary - he turned 35 years old.
The first call from the mobile was produced in 1973, and it took 10 yearsTo bring the invention to the mass consumer.
First mobile phones it was very expensiveAt the same time, to put it mildly, they did not differ in pocket sizes. For each such device weighing 1kg wishing to pay any nor little 3500 dollars.
However, the connection itself was carried out by quite modern principles. –
through basic stations, network which reminds cellsTherefore, this connection is called cellular.
Teacher: Surely you listen to radio programs. What stations? Can you call? And why do you find 20 radio stations on the air, and not 120? What is it connected with?
Pupils respond.
Teacher: And cellular subscribers numbered more than 2 billion. How is such a connection?
The system uses the principle of dividing some territory on zones, or "honeycombs". Each "honeycomb" is served by the transmitter, the radiation of which is well captured only at a distance of 500 m to 10 kilometers - the radius of the cell. In the neighboring cell, this signal is so weaken that it is not captured by the phone. This allows without any mutual interference to use the same frequency re-in another cell. Thus, working on one allocated channel, but with a large number of base stations, cellular communication can cover unlimited areas, connecting a large number of subscribers.
Useful communication? Yes!
Please get your mobile phones.
Are you sure to keep mobile phones in your pockets safely?
What is this device - useful or harmful? Tell me!
Slide 4. Cellular communication - for or against?
Teacher: You have sheets with information on your tables. Appendix 1
. Everyone works with its sheet.
Your task - red (color of danger) allocate information about the harmful effects of cellular communication, and green Information about the benefits of cellular communication. You are given to work 3 minutes.
Students work individually.
Teacher: Show sheets. Something is a long red. Weight must be arguments to use cellular communication! Is it a useful device or harmful?
Students: Useful device, but it is necessary to work out security measures.
Teacher: We continue to work. It is necessary to divide into three groups. Each group will fulfill its task.
The task: 1 The group only works on the arguments in favor of cellular communication, 2 groups - only above the arguments about harmful effects. You need:
1. If possible, combine in 2-3 large blocks by distributing it into categories. Name these categories using no more than 3 words, and picture by Scheme with black marker. Picture 1 .
2. Specific examples from text Use for smaller division. Can give own arguments.
3. The presentation of your work (presentation) can make 1-2 people from the group.
On this job – 5 minutes.
Task 3 group: Discuss all moments for and against and make Rules using mobile phone. Record them on a sheet.
This work is given for 5 minutes.
Groups post their work.
Presentation.Present representatives from groups. The remaining groups can complement.
Teacher: Let's lay priorities. Range the rules as they are significance. Compare those that experts from the Radiometric Control Committee offer.
Slide 5. Precautions:
1. Do not use a cell phone without need
2. Talk to continuously no more than 3 - 4 minutes
3. Do not allow the cell phone to enjoy small children
4. When buying, choose a cell phone with a smaller radiation power
5. In the car, use a cell phone in conjunction with the loud-speaking communication system
Teacher: And now I will conduct an experiment: what is the penetrating ability of mobile phones radiation.
In a thick-walled saucepan (cast-iron), put the phone, call - the connection does not occur. Repeat the call - connects! Students conclude: when repeated call, the signal power increases.
Add item to Rules:
6. When you restart, do not keep the device near the head.
Teacher: What do you choose the most important and interesting thing from today's lesson?
Students answer, reflexion is carried out.
Initially, even before cellular appearance, the radio transmission was carried out directly, from one device to another. Such a system had significant disadvantages:
- The devices could be removed from each other for a distance of several hundred, and even thousand kilometers. Consequently, the transmitters had to have tremendous capacities that the signal reached the target.
- Signals from different transmitters often intersect at one frequency and interfered with each other.
- On one radio frequency channel, only one transmitter could work without interference. Accordingly, the channels lacked.
The use of cellular eliminates us from these problems. Our country is completely covered with a huge number of basic stations - transceiver devices raised above the ground. When making a call, the mobile phone sends the signal not to the phone of the interlocutor, but to the adjacent base station. The base station turns the radio signal into the light, and sends it to the fiber optic cable per switch. The switch redirects the light signal to the base station located near the interlocutor:
As a rule, several base stations are in reach of a mobile phone. The connection occurs with the one that is closer. Given the small distances between the phone and the power station of their transmitters are minimal. I would like to note that the more dense the station will be installed, the more weaker radio emission around us. And if you installed one of these stations directly near you - it's not worth worrying. Radiation from modern mobile stations is very weak, and quickly raging, but radiation from your phone may be repeatedly reduced. About the dangers of mobile phone.
Despite the huge density of base stations, they practically do not intersect at one frequency and do not interfere with each other. How it can be achieved shown in Figure:
Each cell is the main coverage area of \u200b\u200bone of the mobile station. F1-F7 - Radio Frequency Channel Designation. Distance between neighboring stations transmitting at one frequency D,significantly less than their radius action R.. It was from these cells that the name - cellular communication occurred.
