WITH EFFECT FROM THE ACADEMIC YEAR 2016 - 2017

EC303                                                 

ANALOG COMMUNICATION

Instructions                                                                                         4 Periods per week

Duration of University Examination                                                  3 Hours

University Examination                                                                      75 Marks

Sessional                                                                                             25 Marks

 Unit-I

Linear Modulation schemes: Need for modulation, double side band suppressed carrier (DSB-SC) modulation, conventional Amplitude Modulation (AM). Hilbert transform, properties of Hilbert transform. Pre-envelop. Complex envelop representation of band pass signals, In-phase and Quadrature component representation of band pass signals. Low pass representation of band pass systems. Single side band (SSB) modulation and Vestigial-side band (VSB) modulation. Modulation and demodulation of modulation schemes

Unit - II

Angle modulation schemes: Frequency Modulation (FM) and Phase modulation (PM), Concept of instantaneous phase and frequency. Types of FM modulation: Narrow band FM and wide band FM. FM spectrum in terms of Bessel functions. Direct and indirect (Armstrong's) methods of FM generation. Balanced discriminator, Foster–Seeley discriminator and Ratio detector for FM demodulation. Pre-Emphasis and De-Emphasis. Capture effect.

Unit-III

Transmitters and Receivers: Classification of transmitters. High level and low level AM transmitters. FM transmitters. Principle of operation of Tuned radio frequency (TRF) and super heterodyne receivers. Selection of RF amplifier. Choice of Intermediate frequency. Image frequency and its rejection ratio Receiver characteristics: Double spotting, Tracking and alignment, Automatic Gain Control.

Unit-IV

Noise Sources and types. Atmospheric noise, Shot noise and thermal noise. Noise temperature. Noise in two-port network: noise figure, equivalent noise temperature and noise bandwidth. Noise figure and equivalent noise temperature of cascade stages. Narrow band noise representation. S/N ratio and Figure of merit calculations in AM, DSB-SC, SSB and FM systems.

Unit-V

Analog pulse modulation schemes: Sampling of continuous time signals. Sampling of low pass and band pass signals. Types of sampling. Pulse Amplitude Modulation (PAM) generation and demodulation. Pulse time modulation schemes: PWM and PPM generation and detection.

Suggested Reading:

1. 1.Simon Haykin, “Communication Systems,” 4/e, Wiley India, 2011.
2. 2.B.P. Lathi, Zhi Ding, “Modern Digital and Analog Communicaton Systems”, 4/e, Oxford University Press, 2016
3. 3.
4. 4.P. Ramakrishna Rao, “Analog Communication,” 1/e, TMH, 2011.
5. 5.
6. 6.