# BASICS OF ELECTRONICS AND COMMUNICATION PDF

In the crystalline lattice structure of Si, the valence electrons of every Si atom are locked up in covalent bonds with the valence electrons of four neighboring Si. Basics of Electrical,. Electronics and. Communication Engineering. K. A. NAVAS. bestthing.infosor in ECE. Govt. Engineering College. Thrissur The information contained within this Basic Electronics Tutorials guide is provided "as-is" and free of and electronic circuits and soldering irons. Thank you and.

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Communication Systems. ▫ Basic components: ▫ Transmitter. ▫ Channel or medium. ▫ Receiver. ▫ Noise degrades or interferes with transmitted information. Notes for bestthing.info, BE and Diploma in Electronics and Communication Engineering Basic Electronics, Download Basic Electronics-1 Notes · Download Basics. ELECTRONICS AND COMMUNICATION EC09 (P) Digital Electronics Lab .. To expose the students to the basic concepts of electric circuits and their.

What is sampling? The process of obtaining a set of samples from a continuous function of time x t is referred to as sampling. 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. What is pass band? Passband is the range of frequencies or wavelengths that can pass through a filter without being attenuated.

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. 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. 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. Explain RF?

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. 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. Define 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.

Name the modulation techniques. 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.

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

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.

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So if demand exceeds the capacity of a base station an additional base station is needed. What is a base station? How many satellites are required to cover the earth? The life span of the satellite is about 15 years.

## Basic Electronics for Scientists and Engineers

What is a repeater? 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.

## Basic Electronics Books

Attenuation is an important property in telecommunications and ultrasound applications because of its importance in determining signal strength as a function of distance. What is multiplexing? Multiplexing known as muxing is a term used to refer to a processwhere 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. 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. 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. What is a base station? How many satellites are required to cover the earth? The life span of the satellite is about 15 years.

What is a repeater? 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.

What is multiplexing? Multiplexing known as muxing is a term used to refer to a processwhere multiple analog message signals or digital data streams are combined into one signal over a shared medium.

## Electrical Basics

The aim is to share an expensive resource. For example, in telecommunications, several phone calls may be transferred using one wire. Code division multiple access CDMA is a channel access methodutilized by various radio communication technologies. CDMA employsspread-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.

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. 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. 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. 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. What is an Amplifier? An electronic device or electrical circuit that is used to boost amplify the power, voltage or current of an applied signal.

What is Barkhausen criteria? Barkhausen criteria, without which you will not know which conditions, are to be satisfied for oscillations. Explain Full duplex and half duplex. Full duplex refers to the transmission of data in two directions simultaneously. For example, a telephone is a full-duplex devicebecause both parties can talk at once.

In contrast, a walkie-talkie is ahalf-duplex device because only one party can transmit at a time. Most modems have a switch that lets you choose between full-duplex and half-duplex modes.

The choice depends on whichcommunications program you are running. In full-duplex mode, data you transmit does not appear on yourscreen until it has been received and sent back by the other party. This enables you to validate that the data has been accurately transmitted. If your display screen shows two of each character, it probably means that your modem is set to half-duplex mode when it should be in full-duplex mode. 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. Positive feedback: This tends to increase output. 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.

Advantages of negative feedback over positive feedback. Much attention has been given by researchers to negative feedback processes, because negative feedback processes lead systems towards equilibrium states. Modulation Modulation refers to the act of adding information to an electronic or optical waveform. The information may be added by altering the frequency phase of the waveform, its amplitude or more.

Modulation is needed because most of the time information is generated and transmitted via signals having low frequencies. A low-frequency signal is highly susceptible to attenuation and therefore it cannot be transferred to long distant locations. In order to rectify this problem, the original carrier wave having a low frequency is superimposed upon a high-frequency carrier wave. This process is known as modulation. AM and FM are both examples of Modulation.

Demodulation Demodulation reverses modulation. Repeater The job of the repeater is to extend the range of the communication systems by amplifying the signals. The repeaters act as both the sender and the receiver in the communication system.

A weak signal is received at the repeater which is then amplified and re-transmitted.

Noise Any electrical signal that interferes with the information signal is known as noise. It can come from a variety of sources in the environment such as the rain, hailstorms or thunderstorms etc.The base station sends out radio waves, which are detected by your telephone and converted back to speech.

This property makes them useful in electronic filters. What is stop band? Basic quantities 3. Types of feedback: Negative feedback: This tends to reduce output but in amplifiers, stabilizes and linearizes operation. The characteristics amplitude, frequency, or phase of the carrier signal are varied in accordance with the information bearing signal. Class A Amplifiers

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