Quadrature amplitude modulation (QAM) ([pic] /ˈkwɑːm/ or /ˈkæm/ or simply "Q-A-M") is both an analog and a digital modulation scheme. It conveys two analog message signals‚ or two digital bit streams‚ by changing (modulating) the amplitudes of two carrier waves‚ using the amplitude-shift keying (ASK) digital modulation scheme or amplitude modulation (AM) analog modulation scheme. The two carrier waves‚ usually sinusoids‚ are out of phase with each other by 90° and are thus called quadrature carriers
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The advantages of AM radio are that it is relatively easy to detect with simple equipment‚ even if the signal is not very strong. The other advantage is that it has a narrower bandwidth than FM‚ and wider coverage compared with FM radio. The major disadvantage of AM is that the signal is affected by electrical storms and other radio frequency interference. Also‚ although the radio transmitters can transmit sound waves of frequency up to 15 kHz‚ most receivers are able to reproduce frequencies only
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ANALOG COMMUNICATION LAB Amplitude Modulation Date: 4th February 2013 Submitted By ADARSH V R AKHIL KRISHNA R ANANTHU R KRISHNAN ARUN KOSHY T B100291EC B100125EC B100256EC B100091EC S6 ECE Batch: A Contents 1 Introduction 2 Theory 3 Principles and Circuits Used 4 Design 5 Observations and Results 6 Conclusion 3 5 8 15 21 23 2 Chapter 1 Introduction Today‚communication has entered into our daily lives in so many different ways that it is very easy to overlook the multitude
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Systems EEE F311 Contents 1 Aim of the course‚ what to expect? 2 Course content 3 Instructions about the course 4 Introduction/Discussions Aim of the course … Understanding signals and systems Analog & Digital modulation/transmission techniques Understanding important block-sets of communication system Information theory Analysis of communication systems Recent trends in communication References required B.P. Lathi‚ Modern Digital and Analog
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1. A 1.4M Hz carrier is modulated by a music signal that has a frequency components from 20 Hz to 10k Hz. Determine the range of frequencies generated for the upper and lower sidebands. Solution: Upper Side Band = 1‚ 400‚ 000 Hz + 20 Hz = 1‚400‚ 020 Hz Up to = 1‚ 400‚ 000 Hz + 10‚ 000 Hz = 1‚ 410‚ 000 Hz Lower Side Band = 1‚ 400‚ 000 Hz – 10‚ 000 Hz = 1‚ 390‚ 000 Hz Up to = 1‚ 400‚ 000 Hz – 20 Hz = 1‚ 399‚ 980 Hz 2. Determine
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Amplitude modulation or AM as it is often called‚ is a form of modulation used for radio transmissions for broadcasting and two way radio communication applications. Although one of the earliest used forms of modulation it is still in widespread use today. The first amplitude modulated signal was transmitted in 1901 by a Canadian engineer named Reginald Fessenden. He took a continuous spark transmission and placed a carbon microphone in the antenna lead. The sound waves impacting on the microphone
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AMPLITUDE MODULATION AND DEMODULATION : OBJECTIVE : Study how to perform the amplitude modulation and demodulation and to calculate the modulation index for various modulating voltages. Theory : AMPLITUDE MODULATION : Modulation is defined as the process by which some characteristics of a carrier signal is varied in accordance with a modulating signal. The base band signal is referred to as the modulating signal and the output of the modulation process is called as the modulation signal. Amplitude
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Chapter 9 MODULATION AND DEMODULATION D ata modulators‚ especially those intended to produce constantenvelope output signals‚ are “high-leverage” components in that even very small deviations from ideal in their behavior can lead to large degradations in overall system performance. Therefore‚ successful simulation of wireless communication systems depends upon the use of modulator models that capture all of the significant deviations from ideal behavior. In the “usual” development of
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Aim : To design an optical data communication network which uses Offset Quadrature Phase Shift Keying modulation technique. oftSware used : Optisystem Components used: 1) Psuedo Random Bit Sequence Generator 2) RZ Pulse Generator 3) Fork 1x2 4) Oscilloscope Visualiser 5) RF Spectrum Analyser 6) OQPSK Modulator 7) Quadrature De-modulator 8) M-ary Threshold Detector 9) Eye Diagram Analyzer 10) PSK Sequence Decoder
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tutorial‚ QPSK‚ modulation‚ modulator‚ demodulator‚ demodulation May 01‚ 2002 APPLICATION NOTE 686 QPSK modulation demystified Abstract: Readers are presented with step-by-step derivations showing the operation of QPSK modulation and demodulation. The transition from analog communication to digital has advanced the use of QPSK. Euler’s relation is used to assist analysis of multiplication of sine and cosine signals. A SPICE simulation is used to illustrate QPSK modulation of a 1MHz sine
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