Question

Explain some Demodulation techniques ?

Answer 1

Demodulation is the process of removing the initial data-carrying signal from a carrier wave. A demodulator is an electronic circuit (or a computer program in the case of a software-defined radio) that recovers the information content from a modulated carrier wave.

Complete answer:
Demodulation methods vary based on how base-band signal parameters including amplitude, frequency, and phase are transmitted in the carrier signal. A synchronous detector, for example, can be used to detect a signal modulated with a linear modulation such as AM (amplitude modulation). A signal modulated with angular modulation, on the other hand, requires an FM (frequency modulation) or PM (phase modulation) demodulator.These functions are carried out by various types of circuits.

Diode Rectifier envelope detector: Let's take a look at how an amplitude modulated wave is detected and demodulated now. We'll need a diode to rectify the incoming signal, allowing just half of the wave to pass through. Unwanted radio frequency signals are removed using a capacitor, which restores the original shape.

Product Detector: Receiving signals incorporating a mixer's product detector, as well as a local beat frequency oscillator or a carrier injection oscillator, can be used to demodulate an amplitude modulated wave. The basic form should be the local oscillator's inability to synchronize with the incoming signal carrier.

Synchronous Detector: This synchronous detection method allows for optimal efficiency. It uses a commodity detector or a mixer with a synchronized local oscillator to the incoming signal carrier. This is more useful than other AM modulation techniques.

Note: Demodulators are the only devices that can perform techniques like carrier recovery, clock recovery, bit slip, frame synchronization, rake receiver, pulse compression, Received Signal Strength Indication, error detection and correction, and so on.