## Explain Fourier Theory | Properties | Advantages

What is Fourier Theory? Fourier Theory Background:- The mathematical analysis of the modulation and multiplexing methods used in communication systems assumes sine wave carriers and information signals. This simplifies the analysis and makes operation predictable. However, in the real world, not all information signals are sinusoidal. Information signals are typically more complex voice and video … Read more

## Time Domain Versus Frequency Domain

Difference Between Time Domain and Frequency Domain Most of the signals and waveforms that we discuss and analyze are expressed in the time domain. That is, they are variations of voltage, current, or power with respect to time. All the signals shown in the previous illustrations are examples of time-domain waveforms. Their mathematical expressions contain … Read more

## The Importance of Fourier Theory

What Is Importance of Fourier Theory? Fourier analysis allows us to determine not only the sine wave components in any complex signal but also how much bandwidth a particular signal occupies. Although a sine or cosine wave at a single frequency theoretically occupies no bandwidth, complex signals obviously take up more spectrum space. For example, … Read more

## Pulse Spectrum | Characteristic | Properties

Explanation of Pulse Spectrum? The Fourier analysis of binary pulses is especially useful in communication, for it gives a way to analyze the bandwidth needed to transmit such pulses. Although theoretically, the system must pass all the harmonics in the pulses, in reality, relatively few must be passed to preserve the shape of the pulse. … Read more

## The Relationship Between Rise Time and Bandwidth

Rise Time and Bandwidth? Because a rectangular wave such as a square wave theoretically contains an infinite number of harmonics, we can use a square wave as the basis for determining the bandwidth of a signal. If the processing circuit should pass all or an infinite number of harmonics, the rise and fall times of … Read more

## Amplitude Modulation Concepts

What Is Amplitude Modulation? As the name suggests, in AM, the information signal varies the amplitude of the carrier sine wave. The instantaneous value of the carrier amplitude changes in accordance with the amplitude and frequency variations of the modulating signal. Fig. 3-1 shows a  single frequency sine wave intelligence signal modulating a higher-frequency carrier. The carrier … Read more

## Overmodulation

The modulation index should be a number between 0 and 1. If the amplitude of the modulating voltage is higher than the carrier voltage, m will be greater than 1, causing distortion of the modulated waveform. If the distortion is great enough, the intelligence signal becomes unintelligible. Distortion of voice transmissions produces garbled, harsh, or … Read more

## Percentage of Modulation

How to Find Percentage Of Modulation The modulation index can be determined by measuring the actual values of the modulation voltage and the carrier voltage and computing the ratio. However, it is more common to compute the modulation index from measurements taken on the composite modulated wave itself. When the AM signal is displayed on … Read more

## Sideband and the Frequency Domain

What is Sideband? Whenever a carrier is modulated by an information signal, new signals at different frequencies are generated as part of the process. These new frequencies, which are called side frequencies, or sidebands, occur in the frequency spectrum directly above and directly below the carrier frequency. More specifically, the side bands occur at frequencies … Read more

## Amplitude Modulation ( AM ) Power

Explanation of Amplitude Modulation Power? In radio transmission, the amplitude modulation signal is amplified by a power amplifier and fed to the antenna with a characteristic impedance that is ideally, but not necessarily, almost pure resistance. The AM signal is really a composite of several signal voltages, namely, the carrier and the two sidebands, and … Read more