Question :What is the difference between a Verilog task and a Verilog function?

The following rules distinguish tasks from functions:A function shall execute in one simulation time unit;a task can contain time-controlling statements.A function cannot enable a task;a task can enable other tasks or functions.A function shall have at least one input type argument and shall not have an output or inout type argument;a task can have zero or more arguments of any type.A function shall return a single value; a task shall not return a value.

Question :What is a feedback? And explain different types of feedback.:Feedback is a process whereby some proportion of the output signal of a system is passed (fed back) to the input. This is often used to control the dynamic behaviour of the system.Types of feedback:Negative feedback: This tends to reduce output (but in amplifiers, stabilizes and linearizes operation). Negative feedback feeds part of a system's output, inverted, into the system's input; generally with the result that fluctuations are attenuated.Positive feedback: This tends to increase output. Positive feedback, sometimes referred to as "cumulative causation", is a feedback loop system in which the system responds to perturbation (A perturbation means a system, is an alteration of function, induced by external or internal mechanisms) in the same direction as the perturbation. In contrast, a system that responds to the perturbation in the opposite direction is called a negative feedback system.Bipolar feedback: which can either increase or decrease output.

feedback is a process of some part of output is feed in the input that is known as feed back.two type of feedback:negativepositive

feedback is the process in which taking some fraction of output and feed it in input for getting stabilized,noise free output

Feedback is the process in which some portion of output inject in the input through resister network.feedback are of two types : 1)negative feedback2)positive feedback

Feedback is the injection of output signal to part of the system input.

It is positive when output signal is fed without inverting its polarity.

Feedback is negative when output signal is flipped before being added to input

The output signal is connected(fed) to the input signal is called geedback....................They are two types of feedback. 1)Positive feedback 2)Negative feedfack...

Question :Explain AM and FM.

AM-Amplitude modulation is a type of modulation where the amplitude of the carrier signal is varied in accordance with the information bearing signal.FM-Frequency modulation is a type of modulation where the frequency of the carrier signal is varied in accordance with the information bearing signal.

Amplitude Modulation(AM)-In AM,amplitude of the carrier signal is varied in accordance with the baseband signal(original information signal is reffered to as baseband signal such as voice,video etc) keeping phase and frequency constant.In AM,Modulation Index(m)=Em/Ecwhere Em=modulating signal voltageEc=carrier signal voltagewhen Em<=Ec,Modulation Index(m) lies between 0&1 and no distortion is introduced in the AM wave.when Em>=Ec,Modulation Index(m) is greater than 1,this will distort the shape of AM signal and this distortion is called as over modulation.Frequency Modulation(FM)-In FM,frequency of the carrier signal is varied in accordance with the baseband signal kepping phase and amplitude constant.In FM,Modulation Index(mf)=∆fm/fmwhere ∆fm=fmax-fmin/2=Maximum frequency deviationfm=Modulating frequency

Question :What is attenuation?

Attenuation is the reduction in amplitude and intensity of a signal. Signals may attenuate exponentially by transmission through a medium, or by increments calculated in electronic circuitry or set by variable controls. Attenuation is an important property in telecommunications and ultrasound applications because of its importance in determining signal strength as a function of distance. Attenuation is usually measured in units of decibels per unit length of medium (dB/cm, dB/km, etc) and is represented by the attenuation coefficient of the medium in question

Attenuation is the reduction in amplitude and intensity of a signal. Signals may attenuate exponentially by transmission through of the output.

the attenuation is the decrease in the signal strength due to passing through a medium which is noisy..the attenuation causes the amplitude to reduc

attenuation controls the amplitude of input signal

It ruduces the power level of the signal.the resister network is used for this purpose.Attenuation=20log(Vmax/Vmin) IN dB

20log(vmax/vmin)in db=attenutionattenution is done at medium forthat we use a teriminal is called as reasistor it reduce sisnal strenggth and amp,litude levels while propigating throuh medium

it is the process of reducing amplitude of the transmition signal it is know as attenuation

it levels signal

attenuation is the process by which the strength of the signal is to be decreased and at a particular range of a frequency of the signal is to be passed out otherwise its attenuate or in other words sttoped therefore the signal is to attenuated and also occur the reduction in the intensity of that signal.

Reduction of signal strength during transmission.Attenuation is the opposite of amplification and is normal when a signal is sent from one point to another

it attenuates the signal without changing its magnitude.

Attenuation is the reduction in amplitude and intensity of a signal. Signals may attenuate exponentially by transmission through a medium, or by increments calculated in electronic circuitry or set by variable controls. Attenuation is an important property in telecommunications and ultrasound applications because of its importance in determining signal strength as a function of distance. Attenuation is usually measured in units of decibels per unit length of medium (dB/cm, dB/km, etc) and is represented by the attenuation coefficient of the medium in question

Question :What is a semi conductor?

A semiconductor is a solid material that has electrical conductivity in between that of a conductor and that of an insulator(An Insulator is a material that resists the flow of

electric current. It is an object intended to support or separate electrical conductors without passing current through itself); it can vary over that wide range either permanently or dynamically.

Semiconductor is material,thats conducting range is in between conductor and insulator.    

A semiconductor is a solid substance which has an energy gap of 1eV. Which does not conducts at 0'K temperatue. But Conducts by addition of impurities or by

Simple example of that is Diode which is semiconductor. Having two P and N junctions with barrier as insulator between two junctions which are conductor. together called semiconductor

Semiconductors are solid materials with a level of electrical conductivity between that of insulators and conductor

semi means half .that means a semiconductor is half conductor and half insulator .it acts as a insulator at 0 deree celcius or -273k.and acts as a conductor at more than 0degree celcius

semi means half .that means a semiconductor is half conductor and half insulator .it acts as a insulator at 0 deree celcius or -273k.and acts as a conductor at more than 0degree celcius

the material who electrical proporities lay's between conductor and insulater is known semiconductor,,,,,?

as Question :How does a mobile work?

When you talk into a mobile telephone it converts the sound of your voice to radiofrequency energy (radio waves). The radio waves are transmitted through the air

to a nearby base station. The base station then sends the call through the telephone network until it reaches the person you are calling. When you receive a call on your mobile phone the message travels through the telephone network until it reaches a base station near to you. The base station sends out radio waves, which are detected by your telephone and converted back to speech. Depending on the equipment and the operator, the frequency that each operator utilises is 900MHz, 1800MHz or 2100MHz. The mobile phone network operates on the basis of a series of cells. Each cell requires a radio base station to enable it to function.There are three types of base station and each has a particular purpose:The Macrocell is the largest type and provides the main coverage for mobile phone networks.The Microcell is used to improve capacity in areas where demand to make calls is high, such as shopping centres.The Picocell only has a range of a few hundred metres and may be used to boost weak signals within large buildings.Each base station can only cope with a certain number of calls at any one time. So if demand exceeds the capacity of a base station an additional base station is needed.

mobile phone is have transmitter and reciever both so when we call over voice is analog and in mobile we use ADC to convert into digital signal so digital signal first accepted the nearest base station and then it send to the desired mobile number and vice versa process repeat.

When you talk into a mobile telephone it converts the sound of your voice to radiofrequency energy (radio waves). The radio waves are transmitted through the air to a nearby base station. The base station then sends the call to main station the call is now send the main station of the receiver then call again come to base station near to receiver then call is send on receiver mobile.

when we dial a number and make a call then msg will sent to near by base station and then to MTSO(Mobile Telephone Switching Office) the whole operation will be performed by this MTSO thats why we say MTSO as a heasrt of telephone system .After receiving the info MTSO(moreover MTSO receives a unique ID regarding your cell possess ) will sends this info to all base stations so based on this the required number is detected by the base stations which is nearer to person who you called...thats it now we can transmit our msg by converting voice to radio frequency and freq range would be around 800MHZ.Asusual the techniques to overcome dropped calls yep using handoff mechanism....

mobile is a device for 'transreceiver 'is a part in mobile very important part for connecting about

mobile is the electronic devices. it is the heavy information collected.

When a cellular phone is switched on, but is not yet on call, it first scans the group of forward control channels to determine the one with the powerful signal, and then monitors that control channel until the signal drops below operable level. After this it again scans channels to search the strongest base station signal. For each mobile system, the control channels are defined over the entire geographic area covered and

typically make up about 5-6% of the total number of channels available in the system(the remaining are dedicated to voice and data traffic for the end-users). When a call is made to a mobile user, the MSC carry off the request to all base stations in the system. The subscriber?s telephone number is then broadcast as a paging message over all of the forward control channels through out the mobile system. The mobile receives the paging message sent by the base station which it scans, and reacts by identifying itself over the reverse control channel. The base station relays the acknowledgment sent by the mobile and informs the MSC of the handshake. Then, the MSC orders the base station to move the call to a vacant voice channel within the cell. At this point, the base station signals the mobile to change frequencies to a vacant forward/ reverse voice channel pair, at which point another data message is transmitted over the forward voice channel to order the mobile telephone to beep, thereby asking mobile user to answer the phone. Once a call is started, the MSC adjusts the transmitted power of the mobile and varies the channel of the mobile equipment and base stations in order to retain call quality as the user moves in and out of the range of base station. This phenomenon is called as handoff. Special control signaling is enforced to the voice channels so that the mobile unit may be managed by the base station and the MSC while a call is ongoing.When a mobile starts a call, a call startup request is sent on the reverse control channel. With this request the mobile unit forwards its Mobile identification number (MIN), ESN, and the phone number of the called party. The mobile also transfuses a station class mark (SCM) which shows what the maximum transmitter power level is for the particular subscriber. The cell base station acquires this data and sends it to the MSC. The MSC authenticates the request, makes connection to the call party through the PSTN, and orders the base station and mobile user to move to a vacant forward and reverse voice channel pair to permit the conversation to begin.All mobile systems give a service usually called as roaming. This permits users to react in service areas other than the one from which service is undersigned. When a mobile enters a city or area that is different from its home service area, it is registered as a roamer in the new service area. This is executed over the FCC, since each roamer is camped on to an FCC at all times. Every several minutes, the MSC prints a global command over each FCC in the system, asking for all mobiles which are previously not enrolled to report their MIN and ESN over the RCC. New unregistered mobiles in the system regularly report back their user information upon receiving the registration request, and the MSC than uses MIN/ESN information to request billing status from home location register (HLR) for each roaming mobile equipment. If a specific roamer has roaming permission for billing purposes, the MSC registers the user as a valid roamer. Once enrolled, roaming mobiles are allowed to receive and make calls from that location, and billing is routed automatically to the user?s home service provide.

mobile is one which sends or receives a message,it is also called transpounder.mobile converts voice siganal into radio signal this happens when the process is in between sender and receiver ones the received call again the radio signal is converted into voice signal

Question :Example for negative feedback and positiv

Answers:

Example for ?ve feedback is ---AmplifAnd for +ve feedback is ? Oscillators

Question :Where do we use AM and FM?

Answers:

AM is used for video signals for example TV. Ranges from 535 to 1705 kHz.FM is used for audio signals for example Radio. Ranges from 88 to 108 MHz.

AM is used for video signals for example TV. Ranges from 535 to 1705 kHz.FM is used for audio signals for example Radio. Ranges from 88 to 108 MHz.

AM used in tv.these signals range 565 hz to 1650hz..it covers low rangeFM used in radio.these signals range 88 to 108mz.It covers large areas

AM IS USED IN T.V THESE SIGNALS RANGES FROM 565HZ TO 1650HZ.

FM USED IN RADIO SIGNALS RANGES FROM 88 TO 108MZ.

AM is used for motion picture (for video).(535 to 1705kHz)FM is used for voice.(88 to 108MHz)

Question :How many satellites are required to cover the earth

Answers:

3 satellites are required to cover the entire earth, which is placed at 120 degree to each other. The life span of the satellite is about 15 years.

three satellite are required to cover the total earth surface.

actually there are maximum possible 3 satellites are required which are placed apart from 120 degree to each other.

actully there are max 3 satellites th degreeat is rotate 120

Answers:

These are the two different means of mobile communication being presently used worldwide. The basic difference lies in the Multiplexing method used in the aerial communication i.e. from Mobile Tower to your mobile and vice versa.CDMA uses Code Division Multiple Access as the name itself indicates, for example

you are in a hall occupied with number of people speaking different language. You will find that the one language you know will be heard by you and the others will be treated like noise. In the same manner each CDMA mobile communication takes place with a "code" communicating between them and the other end if one is knowing that code then only it can listen to the data being transmitted i.e. the communication is in the coded form.On the other hand GSM (Global System for Mobile Communications) uses narrowband TDMA, which allows eight simultaneous calls on the same radio frequency. TDMA works by dividing a radio frequency into time slots and then allocating slots to multiple calls. In this way, a single frequency can support multiple, simultaneous data channels.

GSM provide international roaming while CDMA does not.

GSM works on 900 and 1800 MHz while CDMA does only on 900 MHz.

Question :What is an Integrated Circuit?

Answers:

An integrated circuit (IC), also called a microchip, is an electronic circuit etched onto a silicon chip. Their main advantages are low cost, low power, high performance, and very small size

Different types(or)thousands electronic components(resistors,transistors,....) of of electronic circuit components are integrated (or)fabricated on a single chip.

An integrated circuit (IC), also called a microchip, is an electronic circuit etched onto a silicon chip. Their main advantages are low cost, low power, high performance, and very small size

ic(integrated circuit) are those circuits on which various electronics component fabricated on a single chip. this chip have small size and we can replace when it get damaged.using ic we can reduce the bulkyness n power of our device.

integration of electronic components in a single chip is called an IC.

electonic circuits r integrated in the silicon chip..for ex: we can connect wires from one component to another. but it takes lots of time and space.but using this chip small space is enough

An integrated circuit(IC) which is also calld as microchip is a electronic circuit which has number of components fabricated on a single silicon chip. By this circuit is less complexity, easy to understand less cost,etc.

IC(integrated circuit) is a miniature, low cost electronic circuit, consisting of active and pasive component . both are unrepairable joint together on a single chip of SILICON is called IC.

fabrication of complete electronic circuit on a small silicon wafer is called IC or integrated circuit.

Question :What is CDMA, TDMA, FDMA?

Answers:

Code division multiple access (CDMA) is a channel access method utilized by various radio communication technologies. CDMA employs spread-spectrum technology and a special coding scheme (where each transmitter is assigned a code) to allow multiple users to be multiplexed over the same physical channel. By contrast, time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency.An analogy to the problem of multiple access is a room (channel) in which people wish to communicate with each other. To avoid confusion, people could take turns speaking (time division), speak at different pitches (frequency division), or speak in different directions (spatial division). In CDMA, they would speak different languages. People speaking the same language can understand each other, but not other people. Similarly, in radio CDMA, each group of users is given a shared code. Many codes occupy the same channel, but only users associated with a particular code can understand each other.

In FDMA(Frequency Division Multiple Access),the available bandwidth of the common channel is divided into bands that are separated by guard bands(to prevent station interferences).Each staion is allocated a band to send its data and also uses a bandpass filter to confine the transmitter frequencies.In TDMA(Time Division Multiple Access),the bandwidth is just one channel that is timeshared between different stations.Each station is allocated a time slot during which it can send data and each station transmits its data in is assigned time slot.In CDMA(Code Division Multiple Access),one channel carries all transmissions simultaneously and using a unique code for each transmitted signal,the mobile and base station are able to distinguish between signals transmitted simultaneously over the same freuqency allocation.CDMA can also be combined with FDMA and TDMA technologies to increase system capacity.

FDMA:--It is one of the multiple-access technique for cellular system.When continuous tansmission is required.-In this technique band width is divided into a no. of channels and distributed among users with a finite portion of band width for permanent use.-It does not required synchronization or timing control.-In wireless communication,it achives simultaneous transmission and reception by using FDD.

TDMA:--In TDMA,the entire band widthis available to the user but only for a finite period of time.-It requires synchronization.-It uses different time slots for transmission and reception.

CDMA:--In CDMA,all the users occupy the same band width,how ever they are all assinged separate codes,which differentiates from each other.-Each user has its own codeward which is orthogonal to thecodes of other users.-Unlike TDMA,CDMA does not require time synchronization.

Question :What is multiplexing?

Answers:

Multiplexing (known as muxing) is a term used to refer to a process where multiple analog message signals or digital data streams are combined into one signal over a shared medium. The aim is to share an expensive resource. For example, in telecommunications, several phone calls may be transferred using one wire.

Multiplexer is nothing but many input signal and only one out put is produce

multiplexing is the process of sending two or more signals through a single communication channel.multiplexing is of two types.1.frequency division multiplexing.(FDM)2.time division multiplexing(TDM).

Multiplexing is a process in analog communication,where multiple message signals are sent over a single communication channel.

multiplexing is the process ,where number of message signals are sent through a common communication channel in such a way that one message signal do not interfere with another message signal.

two or more input and only one output is known as multiplexing.it is 2 type(1)TDM(2)FDM

Question :Name the modulation technique

Answers:

For Analog modulation--AM, SSB, FM, PM and SMDigital modulation--OOK, FSK, ASK, Psk, QAM, MSK, CPM, PPM, TCM, OFDM

Question :1.what is the role of capacitors in the electronic circuits?2.what is the purpose of npn and pnp transistors in the circuits?3.for switching application can i use doide insted of transistor?

Answers:

Think of it as another voltage device in your circuit (similar to a battery). If you connect it to a battery it will charge up to the voltage of the battery. Then, if you remove it from the circuit it will still be charged to the voltage level of the battery!

A lot of answers by others to your question (so I won't repeat here, but they did miss a Tesla coil) have given you applications for this tiny voltage source...however the useful applications really would be unlimited (just like any voltage source is just limited to the electronic designer's imagination).

The capacitor's greatest limitations are that it can only store a limited voltage (so make sure when you use one the voltage rating is high enough for your circuit). Arguably one of its benefits is it can release a whole lot of charge at a rapid rate. They are made with a preferably thin non-conducting material (dielectric) between two metal conductors (plates) which will fail under high voltage. This dielectric is where the energy is actually stored (unlike batteries which typically use a chemical reaction...and thus a more sustained voltage as current is drained).4 years ago

capacitor blocks the direct current nd pas the alternative current.for exp:in fan, capacitor helps tha fan to rotate in one direction due to direct current.fan cant move in both direction as like clock bias nd anticlockbias.

capacitor is a device which is used in circuit for various purpose according to it requirements.example1.C is used to stored charge and capacity of storage is depend on manufacturing purpose.As c charge fully then it lose it charge slowly slowly and act as a battery.2.C also used to attenuate the noise (ac) signal.eg when we connect two device through wire then there must be some noise due to environment that why we used c there and remove the noise.in RC filter.

3.some time we require only dc signal and we want to avoid ac due to that we use C before the required point.

Question :Difference between mobile and a cell phone.

There is no difference, just language use, which differs from country to country, so in Britain it is called a mobile, and in USA and South Africa and other places a cell phone. Even in Europe the name differs. The Germans call it a "handy", which in English has completely another meaning as an adjective, meaning useful. In Italy it is called a telofonino or "little phone". This difference in British and American English is also evident in many other things we use every day, like lifts and elevators, nappies and diapers, pickups and trucks. The list goes on and on, any student of English has to decide which he or she will use, as the default setting.

mobile is a technology and cell phone is sub technology in it. to understand it clearly consider a walkie talkie and cell phone. Both are different technologies but both are mobile. The way they communicate is also different.

Question :State sampling theorem.

It states that, while taking the samples of a continuous signal, it has to be taken care that the sampling rate is equal to or greater than twice the cut off frequency and the minimum sampling rate is known as the Nyquist rate.

A band limited signals of finite energy which has no frequency component higher than fm Hz is uniquely determined by its value at uniform interval less than 1/2fm second apart.fs>=2fmwhere fm=modulating frequencyfs=sampling frequency

Question :What is modulation? And where it is utilized?

Modulation is the process of varying some characteristic of a periodic wave with an external signals. Radio communication superimposes this information bearing signal onto a carrier signal. These high frequency carrier signals can be transmitted over the air easily and are capable of travelling long distances. The characteristics (amplitude,

frequency, or phase) of the carrier signal are varied in accordance with the information bearing signal. Modulation is utilized to send an information bearing signal over long distances.

Modulation is a process in which the baseband signal(original information signal is reffered to as baseband signal such as voice,video etc) modifies the amplitude or phase or frequency of the carrier.Modulation is utilized to avoids mixing of signals,Increase the range of communication and allow adjustment in the bandwidth.

Question :What is demodulation?

Demodulation is the act of removing the modulation from an analog signal to get the original baseband signal back. Demodulating is necessary because the receiver system receives a modulated signal with specific characteristics and it needs to turn it to base-band.

Question :Explain the steps involved in demodulating a signal.

Once the signal is coded, modulated and then sent, the receiver must demodulate the signal. This is usually done in two steps :1. Spectrum spreading (e.g., direct sequence or frequency hopping) modulation is removed.2. The remaining information bearing signal is demodulated by multiplying with a local reference identical in structure and synchronised with received signal.

Demodulation is a technique of removing added carrier frequency to convert back the broadband signal to base band signal

Question :What is stop band?

A stopband is a band of frequencies, between specified limits, in which a circuit, such as a filter or telephone circuit, does not let signals through, or the attenuation is above the required stopband attenuation level.

Question :What is cut-off frequency?

The frequency at which the response is -3dB with respect to the maximum response.

The cut-off frequency is defined as the frequency where the gain has changed by some specified ammount relative to the mean midband gain.

It is the frequency at which the power is half of its max value.

Question :Explain RF?

Radio frequency (RF) is a frequency or rate of oscillation within the range of about 3 Hz to 300 GHz. This range corresponds to frequency of alternating current electrical signals used to produce and detect radio waves. Since most of this range is beyond the vibration rate that most mechanical systems can respond to, RF usually refers to oscillations in electrical circuits or electromagnetic radiation

Question :What is an Integrated Circuit?

An integrated circuit (IC), also called a microchip, is an electronic circuit etched onto a silicon chip. Their main advantages are low cost, low power, high performance, and very small size.

IC stands for INTEGRATED CIRCUIT in the name only itself that all the electronic components are taking and putting at one place(integrated) on a single silicon chip which reduces the size,cost and power usage......

Question :Different types of communications? Explain.

Analog and digital communication.As a technology, analog is the process of taking an audio or video signal (the human voice) and translating it into electronic pulses. Digital on the other hand is breaking the signal into a binary format where the audio or video data is represented by a series of "1"s and "0"s.Digital signals are immune to noise, quality of transmission and reception is good, components used in digital communication can be produced with high precision and power consumption is also very less when compared with analog signals.

There are two types of communication* Analog Communication* Digital CommunicationAnalog Communication: In analog communication system the information bearing signal is continuously varying in both amplitude and time,and it is used directly to modify some characteristics of a sinusoidal carrier wave such as amplitude,phase and frequency.Example: Amplitude Modulation,Frequency Modulation etc.Digital Communication: In digital communication the information bearing signal is processed so that it can be represented by a sequence of discrete message.Example:Pulse Amplitue Modulation(PAM),Pulse Code

Modulation(PCM),Differential Pulse Code Modulation(DPCM),Delta Modulation(DM),Adaptive Delta Modulation(ADM)

There are two types of communication* Analog Communication* Digital CommunicationAnalog Communication: In analog communication system the information bearing signal is continuously varying in both amplitude and time,and it is used directly to modify some characteristics of a sinusoidal carrier wave such as amplitude,phase and frequency.Example: Amplitude Modulation,Frequency Modulation etc.Digital Communication: In digital communication the information bearing signal is processed so that it can be represented by a sequence of discrete message.Example:Pulse Amplitue Modulation(PAM),Pulse Code Modulation(PCM),Differential Pulse Code Modulation(DPCM),Delta Modulation(DM),Adaptive Delta Modulation(ADM)

Question :What is a base station?

Base station is a radio receiver/transmitter that serves as the hub of the local wireless network, and may also be the gateway between a wired network and the wireless network.

Base station is a radio receiver/transmitter that serves as the hub of the local wireless network, and may also be the gateway between a wired network and the wireless network.

Question :What are the functions of Base Station System ( BSS)?Functions of BSS are as follows :1. Radio path control.2. BTS and TC control.3. Connection establishment with MS-NSS.4. Mobility management, speech transcoding.5. Connection of statistical data.

Question :What are different categories of antenna and give an example of each?

Different categories of antenna are as follows :

1. Wire Antennas - Short Dipole Antenna2. Microstrip Antennas - Rectangular Microstrip (Patch) Antennas3. Reflector Antennas - Corner Reflector4. Travelling Wave Antennas - Helical Antennas

5. Aperture Antennas - Slot Antenna6. Other Antennas - NFC Antennas

Question :what is ups and inverters?

While both provide backup power during mains outage, withthe UPS the switch is instantaneous whereas with theInverter there is a gap of a second or two. This gap is OKfor household gadgets such as lights, fans, fridge, etc. butnot OK for computers.

In technical terms:

UPS: The mains power comes to the UPS. The AC is convertedto DC and this DC is constantly charging the battery. Theoutput of the battery is fed to the Sine wave inverter andit converts DC to AC and this feeds the equipment. Sincepower out is always drawn from the battery, there is no timelag when mains swicthes off; it justs stops the battery frombeing charged and the UPS continues to supply power till thebattery runs out.

Inverter: The mains power comes to the Inverter. This isdirectly sent to the output but the AC is also converted toDC and this DC is constantly charging the battery. A sensorand relay mechanism checks whether the mains is ON or OFF.When the main switches OFF, the relay actuator triggers toswitch from mains to inverter. Rest is same like the UPS.Because of this sensor and relay, there is a gap betweentriggering.

UPS involves more costly circuitary and is therefor moreexpensive to make and sell.

Question :What is analog-to-digital conversion of signals?

A discrete-time signal is defined by specifying its value only at discrete times, called sampling instants. When the sampled values are quantised and encoded, a digital signal is obtained. A digital signal is obtained from the analog signal by using an analog-to-digital converter. This entire process is referred to as the conversion of signals from analog to digital form.

Question :What are GPRS services?

GPRS services are defined to fall in one of the two categories :

- PTP ( Point to point)- PTM ( Point to Multipoint)Some of the GPRS services are not likely to be provided by network operators during early deployment of GPRS due in part to the phased development of standard. Market demand is another factor affecting the decision of operators regarding which services to offer first.

Question :What are the advantages of spread spectrum?

SPread spectrum has the following advantages :

1. No crosstalk interference.2. Better voice quality/data integrity and less static noise.3. Lowered susceptibility to multipath fading.4. Inherent security.5. Co-existence.6. Longer operating distances.7. Hard to detect.8. Hard to intercept or demodulate.9. Harder to jam than narrow bands.10. Use of ranging and radar.

SPread spectrum has the following advantages :

1. No crosstalk interference.2. Better voice quality/data integrity and less static noise.3. Lowered susceptibility to multipath fading.4. Inherent security.5. Co-existence.6. Longer operating distances.7. Hard to detect.8. Hard to intercept or demodulate.9. Harder to jam than narrow bands.10. Use of ranging and radar.

Question :What is operating ratio in railway?

Answers:

Operating Ratio = Total revenue / Total expenses