In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted. A modem (from modulator–demodulator) can perform both operations.‎Demodulation · ‎Amplitude modulation · ‎Frequency modulation · ‎Phase modulation. I can't think of no simpler way than this to explain modulation and demodulation. Assume that you want to pass a note to your friend in a building next to will be the block diagrams for modulation and demodulation? This chapter describes the essential principles behind modulation and demodulation, which we introduced briefly in Chapter Recall that our.


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The waveform of this signal is unpredictable.


For example, the waveform of a speech signal is modulation and demodulation in nature and cannot be predicted. In this case, the speech signal is the modulating signal. The other signal involved with the modulation is a high frequency sinusoidal wave.

Modulation - Wikipedia

This signal is called the carrier signal or carrier. The frequency of modulation and demodulation carrier signal is always much higher than that of the baseband signal. After modulation and demodulation, the baseband signal of low frequency is transferred to the high frequency carrier, which carries the information in the form of some variations.

After the completion of the modulation process, some characteristic of the carrier is varied such that the resultant variations carry the information.

Why we require modulation? To improve the quality of reception To increase the range of communication To reduce the antenna height. For narrow banding of signal: Modulation converts a wideband signal into a narrow-band signal whose ratio between highest frequency to modulation and demodulation frequency is approximately one and single antenna will be sufficient to transmit the signal.

modulation and demodulation

Need of Modulation and Demodulation |

The demodulator is the circuit, or for a software defined radio, the software that is used to recover the information content from the overall incoming modulated signal.

Modulation and demodulation or demodulation The terms detection and demodulation are often used when referring to the overall demodulation process.


Essentially the terms describe the same process, and the same circuits. Terms like diode detector, synchronous detector and product detector are widely used.

But the term demodulation tends to be used more widely when referring to the process of extracting the modulation from the signal. This process of imposing an input signal on a carrier wave modulation and demodulation known as modulation and demodulation.

Put differently; modulation modifies the shape of a carrier wave to encode the data information that we intended in carrying.

Demodulation | Amplitude Modulation AM | Electronics Notes

Modulation is similar to hiding a code in the carrier wave. Types of Modulation and demodulation There are three types of modulation namely: Frequency modulation Phase modulation. Amplitude modulation Modulation and demodulation kind of modulation where the amplitude of the carrier signal is changed in proportion to the message signal while the phase and frequency are kept constant.

At the receiver side, the demodulator typically performs: Automatic gain controlAGC to compensate for attenuationfor example fading.

Modulation And Demodulation

Frequency shifting of the RF signal to the equivalent baseband I and Q signals, or to an intermediate frequency IF signal, by multiplying the RF signal with a local oscillator modulation and demodulation wave and cosine wave frequency see the superheterodyne receiver principle.

Sampling and analog-to-digital conversion ADC sometimes before or instead of the above point, for example by means of undersampling. Equalization filtering, for example, a matched filter modulation and demodulation, compensation for multipath propagation, time spreading, phase distortion and frequency selective fading, to avoid intersymbol interference and symbol distortion.