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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