Communication System - I1. Unit-1
2. Unit-2
3. Unit-3
4. Unit-4
5. Unit-5
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Communication System - I SyllabusUnit – I Spectral Analysis: Fourier Series, Normalised power in a Fourier expansion, Power Spectral Density, Fourier transform, Perseval’s Theorem, Power & Cross co-relation, Auto co-relation, Bandlimiting of waveforms. Unit – II Linear Modulation: Amplitude Modulation: Amplitude Modulation, Generation of AM waves, Demodulation of AM waves, Suppressed carrier modulation, DSB-SC modulation, Generation of DSB-SC signals, Detection of DSB-SC signals, Single-tone modulated DSB-SC, Quadrature AM, SSB-SC modulation, Generation of SSB-SC signals, Detection of SSB-SC signals, VSB, Comparison of various AM systems. Unit – III Exponential Modulation: Phase & Frequency Modulation: Mathematical representation of FM & PM signals, S ingle tone FM, Multitone FM, Transmission BW of FM waves, WBFM and NBFM, Generation of FM waves, Demodulation of FM waves, Interference, De-emphasis and Pre-emphasis filtering. Unit – IV Radio Transmitters & Receivers: General block diagram of AM, FM and PM transmitters, Block diagram of high level and low level AM Transmitter, High level transistor collector modulator, Low level transistor modulator, Balanced modulator for SSB generation. Reactance modulator for FM generation, Direct FM transmitter, Indirect (Armstrong) FM transmitter, Block diagram of Stereophonic FM transmitter TRF receivers - sensitivity & Selectivity, Superhetrodyne receivers – image frequency & its rejection, SSB receivers. Block diagram of FM receivers. (This unit should be covered in a Block diagrammatic approach rather than covering the detail of the circuits.) Unit – V Noise in CW Modulation: Various noise sources, Noise calculations for – single noise sources, multiple noise sources, cascade and cascade amplifiers. Noise figure and its measurement, Noise temperature, Equivalent input noise resistance, noise Bandwidth, noise measurement on line and channel. Band – pass noise representation, noise figure calculation for various modulation systems (DSB-AM, DSB-SC, SSB and FM), Effects of transmitter noise. Noise in Angle Modulated systems: Noise in FM systems, Threshold in FM, Threshold improvement through D e-emphasis, Noise in phase modulation. |