Study+Material+for+UPSC+Intervie

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Study material for UPSC Interview: IES interview is a technical interview and most of the questions will be technical in nature .They will ask very less questions form ur bio-data most of the questions will be related to ur subject, job exp and latest technology in case of Electronics&Commnictaion engineering. This material contains following items: 1. General guide lines for UPSC interview 2.

Questions based upon your bio-data

3.

Type of technical questions asked from subject in UPSC in Electronics&Communication Engineering in last 5 years(ECE)

4.

Study -material for latest technology(ECE&EE)

1.General guidelines for UPSC interview: Before actual interview there will be your certificate verification. There are generally 5-6 candidates in one session (There are 2 session 10-1&2-5) so generally time allotted is 30 minute for every candidate but it is liable to vary. There are 4 members in interview panel one will be UPSC member and other 3 will be senior professors/scientists/higher rank officers like DRM/GM/CST from railway/director from research institute etcs.

Basic rules (Do’s and Do not’s) for UPSC Interview: 1. Just after entering in board room greet every one and if lady

member is there then greet her first and then rest of members. No need of greeting one by one say good-morning/evening all of you sirs (by making eye contact to everybody)

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] 2. If lady member is there then say good morning/evening mam and

then say good morning/evening to all of you sirs. (never use madam). 3. When they offer chair then say thank you mam/sir to chairman of your board. 4. Distance between chairman and you will be large so speak loudly. 5. Never interrupt them, 1st let them complete their question. 6. If you don’t know answer of any question then with more

confidence say sorry sir I don’t know or say i studied earlier but this time i m not able to recall. 7. Try to avoid giving wrong answers and some time if you are not

sure about answer you simply say sir I m not sure but i think answer is this. If he tells you correct answer say him/her thank you very much sir/mam. 8. If they offer Tea/water to you then avoid it if possible but don’t

forget to say thank-you sir/mam. 9. Try to answer in a simple language so that chairman can also understand it. Chairman of board is decision maker for your marks and he is generally a non technical person. 10.Don’t contradict yourself in questions related to your bio-data. If you have written any thing related to your hobby, sports, extra activities etc. then you can n’t say sorry sir i don’t know. In interview never get tensed, if u r then hide it. Always give answer with light smiling face. 11.Never give negative answer to anything. Never blame system for anything. Never blame anybody for anything during your interview process. You can’t say our whole system is corrupt .our system is responsible for that etcs. 12. There are 4 members during interview and they ask questions one by one. So maintain eye contact to person who is asking questions and

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] for short while u can see other members also but main focus must be on that person only. 13. Answers must be given in very simple language and upto the points .try to avoid formulas give logical explanation. 14. Be more cautious in questions related to your bio-data and non technical questions. In these questions you can’t say I don’t know. eg. If they ask why do you want to join IES you can’t say sorry sir I don’t know. If you have written some thing in your bio-data then you are supposed to know it. 15. Wear proper dress and if possible don’t use perfume etc. Your cloths must be neat and clean and shoes must be polished. 16. Never use words like social status, social-value, job security& cool job etcs. 17.Try to use words with which you are familiar. For Example if you are answering about routers and not good in packet switching then try to avoid packet switching word, while explaining about router.But at the same time if you are good in packet switching then use word packet switching intentionally. 18. Before leaving room don’t forget wishing every one and saying thank you to all of you sirs.

2.Questions based upon your bio-data: There will not be many questions from this portion but we are giving all possible questions? Q.

some question from your name and what is meaning of your name?

Q. some question can be asked form your place any thing famous from ur place and if anything famous that can also be asked, if any current issue is arising there then plz go through that issue. Q. profession of your parent and why did you not chose that or correlation with present job etc.

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] Q. If any addition degrees like M.Tech then why don’t u want to continue that? Q. If you have any academic break after 12th and B.Tech then explain it. Q. If you got any scholarship and medal then question can be asked? Q. If your university and college has some historical importance then Question can be asked upon this? Q. Many Non technical and non technical questions can be asked related to ur job? (i) why do u want to leave ur previous job (ii) how will u utilise ur previous job exp in IES job? (iii) are you satisfied with ur previous job (iv) what was ur responsibility there? (v) If your previous organisation has some collaboration or done some thing latest then they can ask question on it (vi)

why do u want to join IES by leaving ur previous job?

(vii) Don’t you think your previous job is better than this job? (viii) How did u continue ur preparation in previous job? Q. many questions can be arises with ur hobbies and sports etc. Q. They can ask some technical questions from ur hobby Q. They can also ask some technical question from ur favourite sport Q. questions can be asked on Job preference in your bio-data. Q. why have u given railway as ur 1st option. Q. Many questions asked based upon ur hobby and fav sport? Q. they can ask some technical question related to ur hobby? Q. they can also asked many questions related to ur fav sport?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] Q. They can also some technical question based upon ur fav sport? Q They can also some questions if u held any position in college school etc. Q.

why did you not join private sector?

Q.

Are you preparing for civil service exam?

Q.

Why have you given railway signal as 1st option?

Q.

Why have you given railway store as 1st option?

Q.

How will you improve railway telecom system?

Q.

what can be done to avoid accidents in Indian Railway?

Q.

what can be done to handle fog situations?

Q.

how your previous job experience can be utilised for railway?

3.Type of questions asked in UPSC in last 5 years (Memory based collected from students who appeared for Interview) Subject: Electronics&Communication Engineering we can divide our whole syllabus into following parts from interview point of view. Part-1: Material science, Electronics device circuit, Power electronics, Analog electronics, digital electronics and microprocessor Part-2: Communication system, Electromagnetic theory and Microwave. Part-3: Signal&system, Network, Control &Instrumentation

Material science/EDC&Power electronics:

Q. why silicon is preferred material for semiconductor? why not others? Q. why Carbon can’t be used as Semiconductor it is also from 4th group?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. what is concept of hole and did they exist? Q. does hole physically exist? Q. How will u define mobility? Q. why electron mobility is always higher than holes? Q. what is concept of effective mass? Q. At what factor effective mass depends? Q. what are the disadvantages of Ge as a semiconductor material Q. How silicon helps in fabrication? Q. what is use of SiO2 in case of fabrication? Q. what is use of Al in case of fabrication? Q. what are basic steps of fabricaton? Q. If we want a high speed diode will be prefer Si only? Q. what is value of intrinsic concentration (ni) in case of silicon and Ge at room temperature? And how they changes with temperature? Q. How conductivity varies with temp for semiconductor and metal and why? Q. why in a SC conductivity increases with temp and not in metal? Q. How extrinsic semiconductor are more conductive than intrinsic S.C explain? Q. what is effect of temperature on extrinsic SC Q. what are super conductors? Q. what is ideal behaviour of a super conductor? Q. why their conductivity is very high? Q. what are applications of super conductor?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. Give some example of super conductors? Q. what is BCS theory for super conductor? Q. How N-type SC and P type SC forms? Q. what is effect on doping if temp is increased in case of N type and Ptype? Q. what are direct and indirect band gap SC and their application? Q. Plz explain direct band gap and indirect band gap SC Q. what are applications of direct and indirect band gap SC? Q. what are degenerate semiconductor? And where they are used? Q. what is advantage of degenerate SC in tunnel diode Q. what is the position of Fermi level in degenerate SC Q. what happens on position of Fermi level if doping is increased) Q. How will you define Fermi level? Q. Fermi level is probability of what? Q. where is Fermi level in case of N-type &P –type? Q. what is Fermi level at absolute temperature? Q. where is Fermi level for metals? Q. what are laws other than Fermi-Dirac distribution? Q. What is Hall effect? and its application? Q. Discuss Hall effect for metal, SC&Insulator? Q. For Intrinsic SC Hall coeff is –ve why? Q. For extrinsic hall coeff will be? Q. Can u tell difference between drift and diffusion current?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. which current plays a major role in current of diode and how? Q. what is ohms law for semiconductor? Q. what is concept of drift current? And how it can be increased? Q. Can u explain reverse current in diode and how it varies with reverse voltage? Q. explain concept of photo diode and how it is different form solar cell? Q. Explain working of solar cell? Q. what are photo detector and give some example of it? Q. what is LED and how it works? How it different form LASER? Q. where LED is used? How it is used in Optical fiber? Q. Can u explain concept Of Optical fiber? Q. what are opto-isolator in case of OFC? Q. which light is used in case of OFC? Q. what is Total Internal reflection in OFC? Q. what is difference between Pin diode and APD? Which one is used where? Q. what is working of APD? Q. what is working of PIN diode? Q. What is break down in zener diode? Q. what is avalanche multiplication in zener diode? And what is tunnelling? Q. what is basic difference between 2 mechanism? Q. which one is used for high doping and which one is used for low doping? Q. what is effect of temp in case of avalanche breakdown in zener diode?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. why voltage increases if temp is increased in avalanche breakdown in zener diode? Q. Can u explain Zener as a constant voltage regulator? Q. how zener diode can be used in DC power supply? Q. what are the basic blocks of Power supply? Q. what is the ripple used in a filter? Q. Can u compare HWR and FWR on basis of ripple frequency? And which one is better? Q. which type of transformer is used in power supply and why? Q. what is use of bleeder resistor in case of power supply? Q. what is Form Factor and what is its significance? Q. what is voltage regulation for a power supply? Q. can u differentiate b/w clipper and clamper? Q. Is clipper same as Rectifier followed by clamper? Q. what is voltage doubler /Tripler etc? Q. How forward voltage in a diode changes with temp? Q. Is it same for both Ge and Si? Q. why this value is negative? Q. what is ideality factor in case of diode why this 1 for Ge and 2 for Si? Q. why reverse current change with voltage in case of Si but not in case of Ge. Q. How will u define rectifier and what is its use? Q. what is reverse recovery diode in case of diode used as a switch? Q. How transistor work as an amplifier?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. why there is 180 degree phase shift in case of CE mode and not in case of CB and CC? Q. what is physical meaning of Beta in case of transistor? Q. why base width is narrow and doping light in case of transistor? Q. For high speed transistor what will u do with base doping? Q. what is transit time in case of transistor? Q. what are use of CE CC and CB mode? Q. why CE as an amplifier? Q. why CC for impedance matching? And how it is used there? Q. how CB is used as constant current source? Q. what is early effect in case of transistor? Q. what is punch through? Q. How breakdown occurs before punch through in a transistor? Q. what are advantage of FET over BJT? Q. what are disadvantage of FET over BJT? Q. why FET is more temp stable than BJT? Q. why FET is less noisy than BJT? Q. why FET has high impedance than BJT? Q. Is fabrication easy in case of FET? Q. compare gain bandwidth product b/w FET&BJT? Q. Why BJT as a switch has higher speed than FET? Q. How and when FET is used as Voltage variable Resistor?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. How FET is used as an amplifier in saturation region? Q. Can u explain saturation and active region in FET? Q. what is difference between FET&MOSFET? Q. why MOSFET has high impedance than FET? And what is its order? Q. Can u draw ac model of a transistor? Q. How can u draw h-parameter model with the help of ac model? Q. why h-parameter is called hybrid parameter? Q. Explain variation of different h parameters with respect to temperature? Q. Compare Input impedance, output impedance, voltage gain and current gain for CE CC and CB mode. Q. why CC is used as impedance matching? Q. what is cascade and cascade combination? Q. what are the advantage of cascode? Q. How SCR works? Q. compare power diode and power BJT? Q. explain latching and holding current in SCR? Q. what is the application of SCR? Q. what is dv/dt and di/dt effect in case of SCR? Q. How dv/dt and di/dt can be avoided? Analog electronics/Digital electronics:

Q. why analog is called analog? Q. what is difference between analog and digital?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. How will u calculate voltage amplification of BJT? Q. Can u draw frequency response of BJT? Q. Can u explain every part of frequency response? Q. what are low frequency region mid band frequency region and high frequency region? Q. why gain decreases in low frequency and high frequency? Q. why gain remains constant in mid band frequency region? Q. what are the role of coupling capacitor by pass capacitor and blocking capacitor in BJT amplifier? Q. which one of the following capacitor determines lower cut-off? Q. why gain decreases in high frequency region? Q. what is parasitic capacitance in BJT amplifier? Q. what are the capacitance available in parasitic capacitance? Q. what happens to lower cut-off and higher-cut off in case of multistage amplifier? Q. Please draw RC high pass filter? Q. what happens when a step is given as input to it? Q. when it works like a differentiator? Q. Do values of R&C decide is it differentiator or not? Q. what is the condition for RC high pass as a differentiator circuit? Q. what is the output of RC differentiator if square wave is given as input? Q. Same questions can be asked for RC low pass which is an integrator? Q. what is tilt in case of High pass filter?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. How will u define rise time in case of RC LPF? Q. Can u draw π model of a transistor? Q. what new changes occurs when a transistor is operated at high frequency? Q. what is base spreading resistance? Q. why base spreading resistance occurs? Q. why junction capacitance occurs at high frequency in case of BJT? Q. what are various junction/parasitic capacitance in case of BJT? Q. which capacitance is dominated for calculation of higher cut-off? Q. why h-parameter can’t be used for power amplifier? Q. Can u explain concept of oscillator? Q. is it same for sinusoidal &triangular wave generator? Q. what concept is used for sinusoidal generator Q. what concept is used for triangular wave generator? Q. how RC phase shift oscillators used for sinusoidal wave generator? Q. what are the ranges of RC phase shift oscillator? Q. what is concept of offset nonlinearity in case of RC phase shift? Q. can it be made by FET only or BJT also is used? Q. what is difference between RC phase shift by use of BJT&FET. Q. why RC BJT oscillator uses voltage shunt feed back while RC phase shift FET uses voltage series explain? Q. what factors change frequency of oscillation in both cases? Q. what is concept of wein bridge oscillator and where it is used?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. what are audio frequency and radio frequency oscillator? Q. do both have same concept? Q. what is basic concept of radio frequency oscillator? Q. what elements are used for radio frequency oscillator? Q. is Radio frequency oscillator and Crystal oscillator same? Q. How relaxation oscillators are used for triangular wave generator? Q. what is basic concept of relaxation oscillator? Q. what are Bistable, Monostable &Astable multi-vibrator? Q. how will u decide which one is bistable, monostable&astable. Q. what is stable stable&which is quasi stable state? Q. what is difference between stable state& quasi stable state? Q. How will u use Bistable as a Flipflop? Q. How will u use mono stable as Pulse width modulator? Q. how astable is used as voltage to frequency convertor? Q. how astable works as it has 2 quasi stable states? Q. what is Schmitt trigger? Q. How it is different from astable muti-vibrator? Q. Can u draw input and output for Schmitt trigger Q. show UTP<P in terms of input and output? Q. which mutivibrator is used for clock generation? Q. what are the advantages of negative feedback? Q. compare negative feedback and positive feedback in terms of stability?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. why negative feed-back are stabilised while positive feedback are unstable? Q. how negative feedback improves stability? Q. when one uses negative feedback and when positive feedback? Q. what are DC amplifiers? And what are their applications? Q. what is the problem with DC amplifers? Q. what is the drift problem in case of DC amplifier? Q. How Differential amplifier can remove this problem? Q. explain working of differential amplifers? Q. what are different modes in differential amplifier Q. what are differential mode and common mode in case of differential amplifer Q. what is CMRR and what is physical significance of it? Q. Is CMRR link with noise rejection? What is meaning of infinite value of CMRR? Q. where differential amplifiers are used and what is its use in case of OPAMP? Q. how will u define digital? Q. Is digital& binary are same? Q. what is difference between digital&discrete or both are same? Q. Are analog &continuous same? Q. how will u define continuous&analog? Q. what is difference between both continuous and analog? Q. what is meaning of universal gate? Q. Can MUX be used as a universal gate?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. for (n) variable function implementation what shd be size of MUX Q. what is difference between MUX and encoder? Q. what are encoder? Q. Can u tell one application of encoder? Q. what is decoder and how it is different from encoder? Q. what is priority encoder? Q. where this priority encoder can be used? Q. how will u implement higher order decoder/Mux by lower order? Q . How will u implement 8x1Mux by use of 4X1 MUX? Q. How will u define select lines in case of MUX? Q. Can u design a Full adder with half adder only? Q. what is difference between combination circuit and sequential circuit? Q. what are the advantages of sequential circuits in digital? Q. Is feedback digital circuits same as sequential? Q. what are the basic applications of sequential circuits? Q. how sequential circuits used as a memory elements? Q. Are sequential same as Latch? Q. what is difference between latch and flip-flop? Q. what is basic use of latch? Q. what are transparent latch? Q. can we differentiate latch and flip flop based upon triggering of clock? Q. In microprocessor how a latch is used?

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. what is difference between level triggering and edge triggering? Q. what is basic problem with level triggering? Q. How above problem can be removed by use of edge triggering? Q. what are set up time and hold up time? And wht are their values and their significance? Q. what is their significance in case of level triggering and edge triggering? Q. what is meta stability problem in case of flip-flop? Q. Is it linked with setup time and hold up time? Q. How meta stability can be removed? Q. what is race around condition? Q. why does it occur? Q. does it occur in case of both level and edge triggering? Q. How one can remove race around condition? Q. what is master slave flip-flop? Q. How does it remove race around condition? Q. can u explain working of Master slave FF? Q. can u design MOD-10 counter by use of 4 FFs and NOR gate? Q. In place of NOR gate can we use AND gate? Q. why we will use only NAND and OR gate in above case? Q. For ripple counter can we use D FF or S FFs Q. why only T&JK FFs are used? Q. what are special feature of JK and T FF.

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected]

Q. Does triggering affects MOD of ripple counter? Q. what is basic problem with ripple counter? Q. can u explain glitch problem in ripple counter? Q. How this glitch problem can be removed in ripple counter? Q. what are the advantages and disadvantages of synchronous over ripple? Q. How will u design a synchronous binary counter? Q. what components are required for design of MOD-16 synchronous counter?

4.Study material for Latest technology: Generation of Mobile: 1G: Purely analog 2G: It i mainly for voice and slow transmission 2.5G: So the cellular services combined with GPRS became' 2.5G.' GPRS could provide data rates from 56 kbit/s up to 114 kbit/s. It can be used for services such as Wireless Application Protocol (WAP) access, Multimedia Messaging Service (MMS), and for Internet communication services such as email and World Wide Web access. 2.75G: GPRS networks evolved to EDGE networks with the introduction of 8PSK encoding. Enhanced Data rates for GSM Evolution (EDGE), Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC) is a backwardcompatible digital mobile phone technology that allows improved data transmission rates, as an extension on top of standard GSM. EDGE can be considered a 3G radio technology and is part of ITU's 3G definition, but is most frequently referred to as 2.75G. EDGE was deployed on GSM networks beginning in 2003—initially by Cingular (now AT&T) in the United States. 3G: International Mobile Telecommunications-2000 (IMT-2000), better known as 3G or 3rd Generation, is a family of standards for wireless communications defined by the International Telecommunication Union, which includes EDGE, CDMA2000, the UMTS family as well as DECT and WiMAX. Services include wide-area wireless voice telephone, video calls, and wireless data, all in a mobile environment. Compared to 2G and 2.5G services, 3G allows simultaneous use of speech and data services and

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] higher data rates (up to 14.4 Mbit/s on the downlink and 5.8 Mbit/s on the uplink with HSPA+). Thus, 3G networks enable network operators to offer users a wider range of more advanced services while achieving greater network capacity through improved spectral efficiency. •

GPRS (General Packet Radio Service): It offers high speed data services in GSM network. It uses Packet Mode Technique to transfer data and provides connectivity to Internet. Users will be able to browse Internet using handsets supporting Internet browsing. They will also be able use their e-mail accounts as is being done through landline Internet access. Also browsing of Internet from Laptops and Desktop computers is possible by connecting the computer with the GPRS enabled mobile handset through a data cable or Infrared connectivity. Using GPRS you can download in your mobile the following: • Polyphonic ring tones • MP3 tones • Colour logos • Wallpapers • Videos GSM: Global system for Mobile Communication CDMA: Code Division Multiple Access. GSM networks operate in a number of different frequency ranges (separated into GSM frequency ranges for 2G and UMTS frequency bands for 3G). Most 2G GSM networks operate in the 900 MHz or 1800 MHz bands. Some countries in the Americas (including Canada and the United States) use the 850 MHz and 1900 MHz bands because the 900 and 1800 MHz frequency bands were already allocated. Most 3G GSM networks in Europe operate in the 2100 MHz frequency band. GSM-900 uses 890–915 MHz to send information from the mobile station to the base station (uplink) and 935–960 MHz for the other direction (downlink), providing 125 RF channels (channel numbers 0 to 124) spaced at 200 kHz. Duplex spacing of 45 MHz is used. In some countries the GSM-900 band has been extended to cover a larger frequency range. This 'extended GSM', E-GSM, uses 880–915 MHz (uplink) and 925–960 MHz (downlink), adding 50 channels (channel numbers 975 to 1023 and 0) to the original GSM-900 band. Time division multiplexing is used to allow eight full-rate or sixteen half-rate speech channels per radio frequency channel. There are eight radio timeslots (giving eight burst periods) grouped into what is called a TDMA frame.

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] Half rate channels use alternate frames in the same timeslot. The channel data rate for all 8 channels is 270.833 kbit/s, and the frame duration is 4.615 ms. The transmission power in the handset is limited to a maximum of 2 watts in GSM850/900 and 1 watt in GSM1800/1900.

SIM: One of the key features of GSM is the Subscriber Identity Module, commonly known as a SIM card. The SIM is a detachable smart card containing the user's subscription information and phone book. This allows the user to retain his or her information after switching handsets. Alternatively, the user can also change operators while retaining the handset simply by changing the SIM. Some operators will block this by allowing the phone to use only a single SIM, or only a SIM issued by them; this practice is known as SIM locking, and is illegal in some countries.

WAP (Wireless Application Protocol): It provides a standardized way of linking the Internet to mobile phones. WAP is an application communication protocol. WAP is used to access services and information. It is inherited from Internet standards. It is used for handheld devices such as mobile phones and PDAs. It is a protocol designed for micro browsers. It enables the creating of webapplications for mobile devices WAP uses the mark-up language called WML instead of regular HTML. The WAP facility is available over CSD & GPRS for the CellOne customers. MMS ( Multimedia Messaging Service ): Mobile Messaging is evolving beyond SMS text messaging with the introduction of MMS (Multimedia Messaging Service). MMS delivers a total communication experience, allowing personalized multimedia content such as images, audio, text, video and combinations of these. Multimedia Messaging Service (MMS) is a store and forward messaging service that allows mobile subscribers to exchange multimedia messages with other mobile subscribers. As such it can be seen as an evolution of SMS, with MMS supporting the transmission of additional media types: MMS is an important emerging service, which allows the sending of multiple media in a single message, and the ability to send a message to multiple recipients. The originator can easily create a Multimedia Message, either using a built-in or accessory camera, or can use images and sounds stored previously in the phone (and possibly downloaded from a web site).Even if the recipient phone is not switched on, the Multimedia

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] Message will be stored and sent to the recipient as soon as they switch on their phone. If the recipient has not subscribed to the MMS service, still he/she can view the MMS through internet based on the SMS notification he/she gets. A number of Multimedia Messages can be stored in the users handset and reviewed or forwarded at a later date.

ATM&PVC: (AsynchronousTransferMode&PermanentVirtual circuit): ISDN:(integrated circuit Digital Network):

ISDN Has emerged as a powerful tool worldwide for provisioning of different services like voice, data and image transmission over the telephone line through the telephone network. ISDN is being viewed as the logical extension of the digitalization of telecommunication network and most developed countries are in different stages of implementing ISDN. An ISDN subscriber can establish two simultaneous independent calls (except when the terminal equipment is such that it occupies two 'B' channels for one call itself like in video conferencing etc.) on existing pair of wires of the telephone line (Basic rate ISDN) where as only one call is possible at present on the analog line /telephone connection. The two simultaneous calls in ISDN can be of any type like speech, data, image etc. Services Offered By ISDN Normal Telephone & Fax (G3) Digital Telephone -with a facility to identify the calling subscriber number and other facilities. G4 Fax Data Transmission at 64 Kbps with ISDN controller card Video Conferencing at 128 Kbps Video Conferencing at 384 Kbps (Possible with 3 ISDN lines) Broadband service: BSNL is in the process of commissioning of a world class, multi-gigabit, multi-protocol, convergent IP infrastructure through National Internet Backbone-II (NIB-II), that will provide convergent services through the

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] same backbone and broadband access network. The Broadband service will be available on DSL technology (on the same copper cable that is used for connecting telephone), on a countrywide basis spanning 198 cities. In terms of infrastructure for broadband services NIB-II would put India at par with more advanced nations. The services that would be supported includes always-on broadband access to the Internet for residential and business customers, Content based services, Video multicasting, Video-on-demand and Interactive gaming, Audio and Video conferencing, IP Telephony, Distance learning, Messaging: plain and feature rich, Multi-site MPLS VPNs with Quality of Service (QoS) guarantees. The subscribe will be able to access the above services through Subscriber Service Selection System (SSSS) portal.

Important Terms in modern communication: Wi-Fi: Wireless fidelity 1. Wi-Fi allows local area networks (LANs) to be deployed without

wires for client devices, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs. 2. Wireless network adapters are now built into most laptops. The price of chipsets for Wi-Fi continues to drop, making it an economical networking option included in even more devices. Wi-Fi has become widespread in corporate infrastructures. 3. Different competitive brands of access points and client network interfaces are inter-operable at a basic level of service. Products designated as "Wi-Fi Certified" by the Wi-Fi Alliance are backwards compatible. Wi-Fi is a global set of standards. Unlike mobile telephones, any standard Wi-Fi device will work anywhere in the world. 4. Wi-Fi is widely available in more than 220,000 public hotspots and tens of millions of homes and corporate and university campuses worldwide.[12] The current version of Wi-Fi Protected Access encryption (WPA2) is not easily defeated, provided strong passwords are used. New protocols for Quality of Service (WMM) make Wi-Fi more suitable for latency-sensitive applications.

Wi-MAX: worldwide Interoperabilty for Microwave Access

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes, from point-to-multipoint links to portable and fully mobile internet access. The technology provides up to 3 Mbit/sec broadband speed without the need for cables. The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access). The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL

What is electronics? Electronics is flow of electrons or other electrically charged particles in semiconductor in a controlled manner but electrical is study of presence or movement of electric charge.

Microwave oven: It uses Magnetron microwave and generates microwave at frequency of 2.45 GHz for purpose of cooking of food. This is based on molecule of water and other components and other compounds which rotate or vibrate and due to this vibration heat is generated. Every organic matter is generally made up of matter.

Different microwave frequency band: L, S, C, X, Ku, K, Ka(1-40GHz) and other higher frequency bands are as follows: 1. Q-band(30-50) 2. U-Band(40-60) 3. V-band(50-75) 4. E-band(60-90) 5. W-band(75-110)

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] 6. F-Band(90-140) 7. D-band(110-170)

Cable TV: CATV (Community Antenna TV) CATV is a system of providing TV FM radio programming and other services to consumer via radio frequency signals transmitted directly to people’s TV through optical fiber and Co axial cable. In case of radio broad casting use of different frequency allow many channels to be distributed through same cable without separates wires for each. Here tuner of TV-VCR (Video-Cassette-Recorder). Since here a point is operating like an antenna from where many house holds are taking cables so it is known as community antenna TV.

Plasma TV: It is an emissive flat panel display. It is lighter and much thinner than traditional TV and video display .In Plasma TV light is emitted by phosphorous which is excited by plasma discharge between two flat panels of glass. Thickness of plasma is less than 10 cm. There is Neon and Xenon gas in plasma TV which is contained between hundred of tiny cells. Phosphorus in a plasma display give-off coloured light when they are excited. Contrast ratio of plasma TV is 5000:1. Main advantage of plasma TV is that a very wide screen can be produced using extremely thin materials. In plasma each pixel is lit individually so image is very bright and looks good from almost every angle.

Plasma state: It is an ionised gas and considered to be a distinct phase of matter, here ionised means at least one electron has been disassociated from a significant fraction of molecule. Plasma are most common phase of matter and entire visible universe out side solar system is plasma. LCD : It is a thin flat display device made of any number of colour or monochrome pixels arrayed in front of a light source or reflector. It uses a very small amount of power and ie. Why suitable for use in battery powered electronic devices. LCD works on concept of optical polariser. For colour LCD 3sub pixels are used which are coloured as red, green and

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] blue. Main advantage of LCD is less power consumption and its disadvantages are lower contrast ratio and larger response time.

Analog&Digital TV: Analog TV encodes television picture information as an analog signal ie. By varying the voltage or frequency of signal. Common Analog TV system are NTSC (National Television system Committee) and PAL(Phase Alternating Line). Digital TV uses digital modulation and compression to broad cast video audio and data signals. It can be used to carry more channels in some amount of bandwidth than analog TV and it receive high definition programming. This digital signal eliminates common analog broad casting defects such as ghosting, static noise etcs. Aspect ratio in case of digital TV is 16:9 while in analog it is 4:3.

High-Definition-TV(HDTV): It has higher resolution than traditional formats like NTSC, PAL etcs. HDTV is broadcasted generally and therefore coincides with introduction of digital TV. High definition means TV or display is able to accept video over a HDMI connection using a new connector known as HDMI. HDTV has aspect ratio of 16:9 and thus effective resolution is increased.

High Definition Multimedia Interface (HDMI): It provides an interface between any compatible digital audio video/audio source such as set-top-box, DVD player and digital TV. HDMI supports standard, enhanced or high definition video plus multichannel audio on a single cable.

Direct to Home (DTH): It is a term that describes satellite television service which is delivered via communication satellite.

Radio frequency:

PANACEA IES/GATE INSTITUTE (The best institute for Electronics&Communication Engineering) under the guidance of yogesh Agrawal (IES&GATE topper with 7-8 yrs teaching exp) Jiasarai Delhi:Ph09811382221,01132662945,[email protected] It is a portion of electromagnetic spectrum in which electromagnetic waves can be generated by AC fed to an antenna. Generally RF range is between 3Hz-300GHz.

Sub-marine cable: This is cable laid beneath the sea to carry telecommunication between countries. Normal radio communication can’t travel through thick conductors such as salt water. VLF(3-30 KHz) can penetrate sea water down to a depth of roughly 20 meter hence a submarine staying at shallow depth can use these frequencies.

Repeater: It is an analog device that amplifies an input signal which may be either digital or analog. Repeaters are used in both copper wire cables and optical fiber carrying light. Repeaters are used in broadcasting where they are known as booster.

FCC- Rules :( Federal Communication Commission) These are certain rules and which governed all radio spectrums in world wide.

Short wave: (3MHz-30MHz) Short wave frequencies are capable of reaching other side of planet because they can be reflected by ionosphere. SW are used for domestic broad casting in countries with a widely dispersed population and also for international broad casting.

Medium wave (300 KHz-3MHz) It is standard AM broad cast band. These waves have property of following curvature of earth i.e ground wave at all times and also reflect ionosphere. Medium wave is ideal for both local and continent worldwide.

Long wave (