Learn Analog Communication : From Basics to Advance

Learn amplitude modulation by examining how a low frequency modulating signal alters the amplitude of a high frequency carrier to generate the modulated signal, within a continuous modulation framework.

Explore amplitude modulation fundamentals and derive carrier and sideband relationships in AM signals. Calculate bandwidth, power, and the modulation index with worked examples.

Explore multitone amplitude modulation, where the modulating signal contains multiple frequencies. Analyze the AM signal with a carrier, sidebands, bandwidth, and the total modulation index from summed tones.

Switching modulator uses two switching devices to achieve am-like modulation, preserving center frequency fc and bandwidth, with operation depending on carrier amplitude exceeding the modulating signal and resulting on/off states.

Explore the synchronous detector for demodulating double sideband with carrier signals, contrast with envelope detectors, and examine quadrature null effects and why single sideband modulation can be more efficient.

Analyze synchronous detection for single sideband demodulation and vestigial sideband techniques, and compare these with envelope, DSB, and traditional demodulation in analog communication.

Compare amplitude modulation techniques—DSB with carrier, DSB-suppressed carrier, SSB, and vestigial sideband—covering time and frequency domain representations, bandwidth, efficiency, and radio broadcasting applications.

Explore how a modulating signal determines a frequency modulated carrier through frequency deviation and modulation index, illustrating how the carrier frequency sweeps between limits while preserving carrier amplitude.

Explore narrowband FM (NBFM): a single-tone modulating signal yields a low modulation index (β<1) and a compact carrier–sideband spectrum, contrasting with wideband FM (β≥1).

Explore the wideband fm concept through an ideal representation, revealing infinite sidebands and infinite bandwidth. Apply the 70 percent amplitude rule to extract a practical spectrum.

Explore wideband FM concepts by deriving a finite number of sidebands, understand bandwidth limits up to 200 khz per FCC, and analyze carrier, sidebands, modulation index, and efficiency.

Generate nbpm and nbfm using a balanced modulator with carrier and modulating signals under narrowband conditions, including 90-degree phase shifts and fm-pm relationships.

Solve problems on frequency modulated signals, compute total modulation index for orthogonal modulating signals, determine frequency deviation and bandwidth, and classify as narrowband or wideband fm with percentage modulation.

Contrast AM and FM by how the carrier amplitude or frequency follows the modulating signal; explain modulation index, bandwidth, and FCC standards for radio broadcasting, plus linear vs nonlinear modulation.

Learn how a radio receiver picks up modulated radio frequency signals, recovers the baseband information, and tunes with LC circuits and tuned amplifiers while managing bandwidth and quality factor.

Understand how superheterodyne receivers convert high frequencies to an intermediate frequency to improve selectivity and avoid image interference, aided by radio-frequency amplification, tuning circuits, and demodulation.

Explains super-heterodyne receivers, image frequency, and image rejection ratio, using station frequency, intermediate frequency, and quality factor, with AM receiver examples around 455 kHz.

this lecture explains why pre-emphasis and de-emphasis circuits are used in fm transmission to boost high-frequency components at the transmitter and restore them at the receiver, improving signal-to-noise ratio.

Explore frequency discrimination methods using tuning circuits, envelope detectors, and 180-degree phase shifts, outlining fast discriminators, ratio detectors, and the balance slope detector for demodulation.

Explore how a phase-locked loop demodulates frequency-modulated signals by using a voltage-controlled oscillator, mixer, phase detector, and loop filter to recover the modulating signal.