ACS (B-TECH Electronics and Communication Engineering 5th)

Base Band Signals and Systems: 

Introduction, Elements of communication system,

Modulation & Demodulation, Mixing; Linear & Nonlinear, need of modulation, types of

modulation systems, basic transmission signals.

Analog Modulation Techniques:

Introduction, theory of amplitude modulation; AM power

calculations, AM current calculations, AM modulation with a complex wave, theory of

frequency modulation; mathematical analysis of FM, spectra of FM signals, narrow band of

FM, Wide band FM, Theory of phase modulation, phase modulation obtained from frequency

modulation, comparison of AM & FM, Comparison of PM & FM.

AM Transmission:

 Introduction, generation of Amplitude Modulation, Low level and high

level modulation, basic principle of AM generation; square law modulation, Amplitude

modulation in amplifier circuits, suppressed carrier AM generation (Balanced Modulator) ring

Modulator, Product Modulator/balanced Modulator.

AM Reception:

Receiver Parameters; Selectivity, Sensitivity, Fidelity, Tuned Ratio

Frequency (TRF) Receiver, Super heterodyne Receiver; Basic elements of AM superheterodyne

Receiver; RF Amplifier, Neutralization of RF Amplifiers, Class of operation of RF

Amplifiers, High power RF Amplifiers, Image Frequency Rejection, Cascade RF Amplifier,

methods of increasing Bandwidth, frequency Conversion and Mixers; Additive Mixing, Bipolar

Transistor Additive Mixer, self exicted Additive Mixers, multiplicative mixing, Multiplicative

Mixer using dual gate MOSFET, Tracking & Alignment, IF Amplifier, AM detector; square law

detector, Envelope or Diode detector, AM detector with AGC, Distortion in diode detectors,

AM detector Circuit using Transistor, Double hetro-dyne receiver, AM receiver using a phase

locked loop (PLL, AM receiver characteristics.

FM Transmission:

 FM allocation standards, generation of FM by direct method, varactor

diode Modulator, Cross by Direct FM Transmitter, Phase-Locked-Loop Direct FM

Transmitter, Indirect generation of FM; Armstrong method, RC phase shift method,

Frequency stabilised reactance FM transmitter.

FM Reception: 

Frequency demodulators, Tuned circuit frequency discriminators; Slope

Detector, Balance Slope Detector, Foster Seeley discriminator, Ratio Detector, FM detection

using PLL, Zero crossing detector as a Frequency Demodulator, quadrature FM

demodulator, pre emphasis and de emphasis, limiter circuits, FM Capture effect, FM receiver,

FM stereo transmission and reception, Two way FM Radio Transmitter and Receiver.

SSB Transmission:

 Introduction, Single Side band systems, AM-SSB; Full carrier,

Suppressed carrier , reduced carrier, Independent side band, and Vestigial side band,

Comparison of SSB Transmission to conventional AM, Generation of SSB; Filter method,

Phase Shift Method, Third Method.

SSB Reception: 

SSB Product Demodulator, Balanced Modulator as SSB Demodulator,

Single Side band receivers; Single side band BFO Receivers, Coherent Single side band

BFO Receivers, Single Side band Envelop detection receiver, Multi Channel Pilot Carrier

SSB Receiver.

Pulse Modulation Transmissions and Reception:

Introduction, Sampling Theorem PulseAmplitude Modulation

 (PAM), Natural PAM Frequency Spectra for PAM , Flat-top PAM,Sample and hold circuits

, Time division Multiplexing, PAM Modulator Circuit, Demodulationof PAM Signals, Pulse T

ime Modulation (PTM); Pulse Width Modulation(PWM), Pulse position Modulation (PPM)

P, PPM Demodulator.

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