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Unformatted text preview: 9/2/2010 1 EEN 404 EEN 404 Communication Systems Communication Systems Ch3.1a Double Ch3.1a Double-Sided Modulation Sided Modulation Amplitude Modulation Amplitude Modulation 2 Basic Modulation Techniques Basic Modulation Techniques Introduction to modulation ♦ Motivation raising the signal spectrum to a frequency for i) efficient radiation i) efficient radiation ii) antennas of reasonable size iii) government (FCC) requirement multiplexing – multiple signals are transmitted simultaneously multi-component signal: e.g., audio has only one component, but color TV has RGB components and different intensity for each 3 ♦ Model message signal m(t) transmitted signal is the carrier amplitude is the carrier frequency is the carrier phase the message signal m(t) is transmitted through the communication channel by impressing (modulating) it on x c (t) 9/2/2010 2 4 • transmitted signal • If m(t) is impressed on x c (t) in linearly linear modulation phase modulation frequency modulation frequency modulation 5 ♦ Classification: Linear modulation Phase modulation Digital Analog Angle modulation Analog pulse modulation (PM) Freq. modulation (FM) Continuous-wave modulation 6 Linear Modulation Linear Modulation...
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- Spring '10
- coherent, modulation Phase modulation, Modulation DoubleAmplitude Modulation, frequency modulation modulation