UNIT- I
Introduction: Elements of communication systems, Modulation, Modulation Methods and its need, Frequency mixer, EM Spectrum and its Applications. Amplitude Modulation & Demodulation: DSB-FC(AM)modulation& its demodulation,Generation of AM signals, sideband and carrier power of AM, Double sideband suppressed carrier (DSB-SC) modulation & its demodulation, Single sideband (SSB) transmission, Time domain representation of SSB signals & their demodulation schemes (with carrier, and suppressed carrier), Generation of SSB signals, Features of Vestigial sideband (VSB)modulation, Comparison of various amplitude modulation techniques, AM Transmitters, Illustrative Problems.
UNIT- II
Angle Modulation & Demodulation: Concept of instantaneous frequency, Generalized concept of angle modulation, Bandwidth of angle modulated waves – Narrow band frequency modulation (NBFM) and Wide band FM (WBFM), Phase modulation, Generation of FM waves – Indirect method, Direct method. Demodulation of FM, Pre-emphasis& De-emphasis filters, Non-linear effects in FM systems, FM Transmitter, Illustrative Problems.
UNIT- III
Noise in Communication Systems: Types of noise, Time domain representation of narrowband noise, filtered white noise, Quadrature representation of narrowband noise,
Envelope of narrowband noise plus sine wave, Noise equivalent bandwidth, Effective noise temperature, and Noise figure. Performance analysis (i.e. finding SNR expression) of AM,
DSB-SC, SSB-SC, FM, PM in the presence of noise, Illustrative Problems.
UNIT- IV
Analog pulse modulation schemes: Pulse amplitude modulation – Natural sampling, flat top sampling, Sampling theorem and its reconstruction. Pulse amplitude modulation (PAM) & demodulation, synchronization in PAM modulation. Pulse-Time Modulation – Pulse Duration and Pulse Position modulations, and demodulation schemes, Illustrative Problems.
UNIT- V
Radio Receivers & Information theory: Sensitivity, Selectivity, and Fidelity. Superheterodyne AM & FM receivers. Multiplexing systems: Quadrature amplitude modulation (QAM), Frequency division multiplexing (FDM), Time division multiplexing(TDM). Information theory: Introduction, Information content of message, Entropy, mutual information, and channel capacity theorem, Shannon‘s encoding algorithm