CHAPTER 1
DEFINITION
1.1 Definition
“Audio amplifier is defined as the device which is used to convert the audio signal into a electrical signal and then amplify it to a specific level.”
Or
“Audio amplifier is a device which selects the frequency of audio range i.e. 20Hz to 200 kHz and amplifies that frequency signal.”
Audio amplifier works with some basic components of electronics these are microphone, operational amplifier, transistors & speaker. The microphone collects the audio signal an ....etc

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Digital Audio's Final Frontier-Class D Amplifier - Seminar Reports ...
Digital Audio's Final Frontier-Class D Amplifier - Seminar Reports ... ....etc

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Abstract:

Digital audio broadcasting, DAB, is the most fundamental advancement in radio technology since that introduction of FM stereo radio. It gives listeners interference - free reception of CD quality sound, easy to use radios, and the potential for wider listening choice through many additional stations and services.

DAB is a reliable multi service digital broadcasting system for reception by mobile, portable and fixed receivers with a simple, non-directional antenna. It can be operated at any frequency from 30 MHz ....etc

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Digital technology continues its march from media like CDs and DVDs toward your audio speakers. Today, amplifiers based on digital principles are already having a profound effect on equipment efficiency and size. They are also beginning to set the standard for sound quality.

An old idea, the Class D amplifier has taken on new life as equipment manufacturers and consumers redefine the musical experience to be as likely to occur in a car, on a personal stereo, or on an airplane as in a living room. For most consumers today, portability and st ....etc

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Circuit of an automatic switch for audio power amplifier stage is presented here. The circuit uses stereo
preamplifier output to detect the presence of audio to switch the audio power amplifier on only when
audio is present. The circuit thus helps curtail power wastage. IC1 is used as an inverting adder. The
input signals from left and right channels are combined to form a common signal for IC2, which is used
as an open loop comparator. IC3 (NE556) is a dual timer. Its second section, i.e., IC3(b), is configured
as mono ....etc

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CLASS-D AMPLIFIERS
Abstract
Class D amplifiers present us with a revolutionary solution, which would help us eliminate loss and distortions caused due to conversion of digital signals to analog while amplifying signals before transmitting it to speakers. This inchoate piece of knowledge could prove to detrimental in improving and redefining essence of sound and take it to a different realm.

This type of amplifiers do not require the use of D-A conversion and hence reduce the costs incurred for dev ....etc

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Audio Amplifier Circuit



In the first part of lab#1 you will construct a low-power audio amplifier/speaker driver based
on the LM386 IC from National Semiconductor. The audio amplifier will be a selfcontained, battery-operated component. In the second part of the lab you will construct a
microphone circuit using a compact electret condenser microphone cartridge. These circuit
modules are important building blocks of many audio communications systems, and will be
used in our ultrasonic transceiver system. ....etc

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Digital Audio's Final Frontier-Class D Amplifier

Digital technology continues its march from media like CDs and DVDs toward your audio speakers. Today, amplifiers based on digital principles are already having a profound effect on equipment efficiency and size. They are also beginning to set the standard for sound quality.

An old idea, the Class D amplifier has taken on new life as equipment manufacturers and consumers redefine the musical experience to be as likely to occur in a car, on a perso ....etc

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In the output stages of most broadcastreceivers and some amplifiers,there is a limit up to which maximumpower can be developed withoutdistortion. In the widely acceptedoutput circuit, two output transistorsare connected in series between thepositive and ground and biasing is adjustedso that each transistor gets halfthe supply voltage.The circuit presented here is asimple audio amplifier for a personalstereo system. In this, supply voltageto each transistor can be enhanced toproduce a larger output. The audiodriver transformer drives the transis ....etc

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Digital technology continues its march from media like CDs and DVDs toward your audio speakers. Today, amplifiers based on digital principles are already having a profound effect on equipment efficiency and size. They are also beginning to set the standard for sound quality.


An old idea, the Class D amplifier has taken on new life as equipment manufacturers and consumers redefine the musical experience to be as likely to occur in a car, on a personal stereo, or on an airplane as in a living room. For most consumers today, portability and ....etc

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