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2 edition of Amplitude modulation of acoustic signals by ocean waves and the effect on signal detection found in the catalog.

Amplitude modulation of acoustic signals by ocean waves and the effect on signal detection

by James Blenn Perkins

  • 117 Want to read
  • 23 Currently reading

Published by Naval Postgraduate School in Monterey, California .
Written in English

    Subjects:
  • Physics

  • ID Numbers
    Open LibraryOL25327223M

    Like this book? You can publish your book online for free in a few minutes! For instance, if a volt, 1 MHz sine wave is fed into an antenna, the resulting radio wave can be detected in the next room, the next country, and even on the next planet. Modulation is the process of merging two signals to form a third signal with desirable characteristics of both. This always involves nonlinear processes such as.

    What is Amplitude Modulation? Amplitude modulation is defined as the multiplication of one time-domain signal by another time-domain signals may or may not be complex in nature, i.e., either or both signals may contain harmonics components. It is impossible to have amplitude modulation unless at least two different signals are involved. The signals may be . Modulation Effects. Modulation is a non-linear effect in which several signals interact with one another to produce new signals with frequencies not present in the original tion effects are the bane of the audio engineer, for they produce "intermodulation distortion", which is annoying to the music are many forms of modulation, including frequency and amplitude.

    The shape of the time domain waveform is not important in these signals; the key information is in the frequency, phase and amplitude of the component sinusoids. The DFT is used to extract this information. An example will show how this works. Suppose we want to investigate the sounds that travel through the ocean.   Amplitude modulation is a process where you vary the amplitude of a wave of higher frequency with respect to the instantaneous amplitude of a lower frequency wave (modulating signal) So the final output of AM wave will have different amplitudes .


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Amplitude modulation of acoustic signals by ocean waves and the effect on signal detection by James Blenn Perkins Download PDF EPUB FB2

Amplitude modulation of acoustic signals by ocean waves and the effect on signal detection. Item Preview remove-circle Amplitude modulation of acoustic signals by ocean waves and the effect on signal detection. by Perkins, Pages: In this context, this paper has been devoted to investigate the modulation in amplitude for acoustic waves by using nonlinear optical signals in bimetallic Au-Pt NPs and ethanol based nanofluids.

In this work, we highlighted the effect of third-order optical nonlinearities in the automatic modification of the amplitude of acoustical signals Cited by: 4. Amplitude modulation - AM 5 T5: vary the DC voltage magnitude with the gain control ‘g’ of the ADDER.

Notice that the sine wave will move up and down as the DC is varied, its mean value equalling the DC value. Set ‘g’ so that the sinewave peaks just fall to Size: KB.

AMPLITUDE MODULATION AND DEMODULATION © Frank Dörenberg N4SPP V output. mo(t) of this detector consists of a DC signal, the modulating signal, and the secondorder - harmonic (= double) of the carrier frequency: Using. we obtain. That is, a DC term plus the modulating signal.

A small frequency modulation is then applied to one of the PZTs. This leads to an amplitude modulation in the output power that is detected using a phase-sensitive detector and fed back to the other PZT as a correction signal. The frequency control system employs a photodiode, low-noise amplifier, coherent filter and phase-sensitive detector followed by an integrating.

Amplitude modulation is defined as the process in which the amplitude of the carrier wave c(t) is varied about a mean value, linearly with the baseband signal.

An AM wave may thus be dscribed, in the most general form, as a function of time as follows. S(t)=A c {1+K am(t)}cos(2πf c t) Where K a - Amplitude sensitivity of the modulatorFile Size: 3MB. Where: A = the carrier amplitude.

M = the modulation amplitude and is the peak change in the RF amplitude from its un-modulated value. Using the equation above it can be seen that a modulation index of means that the signal will increase by a factor of and decrease to of its original level.

The basic theory and equations behind amplitude modulation are relatively straightforward and can be handled using straightforward trigonometric calculations and manipulation. Essentially an amplitude modulated wave consists of a radio frequency carrier - a sine wave at one frequency, typically in the radio frequency portion of the spectrum.

In frequency modulation the amplitude is kept constant and the frequency is modulated by the amplitude of the modulating signal.

The modulation index for fm is. m = maximum frequency deviation/modulating frequency. FM signal can be represented as: v = ac sin(wct + m sin wmt) ABSTRACT.

Frequency modulation is a type of modulation where the. Chap. 3: Amplitude (Linear) Modulation accordance with a modulation signal is called MODULATION.

• A common form of the carrier we will use, is a sinusoidal wave. Let c(t) −−carrier wave/signal m(t) −−modulating signal • m(t) modulates c(t) by File Size: 1MB.

Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. In amplitude modulation, the amplitude (signal strength) of the carrier wave is varied in proportion to that of the message signal being transmitted.

Start studying NCTI - Installer Book. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Amplitude modulation Possibly the most obvious method of modulating a carrier is to change its amplitude in line with the modulating signal.

The simplest form of amplitude modulation is to employ a system known as ‘on–off keying’ (OOK), where the carrier is simply turned on and off. Frequency Modulation (FM Modulation)- FM Wave Equation- Modulation Index of FM FM demodulation slope detection - Duration: GATE Modulation,Introduction to Amplitude Modulation.

The equation for amplitude modulated wave (m), in case of a sinusoidal signal wave on higher frequency carrier wave (p) is given as This is described in Amplitude modulation views. For a perfect modulation, the value of modulation index should be 1, which implies the percentage of modulation should be %.

For instance, if this value is less than 1, i.e., the modulation index isthen the modulated output would look like the following figure. It is called as Under-modulation. Such a wave is called as an under. The signals that most simply and directly represent the bit stream are called the baseband signals.

We discussed in Chapter 10 why it is generally un-tenable to directly transmit baseband signals over communication links. We reiterate and elaborate on those reasons in Sectionand discuss the motivations for modulation of a baseband signal.

Demodulation is extracting the original information-bearing signal from a carrier wave.A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated carrier wave.

There are many types of modulation so there are many types of demodulators. The signal output from a demodulator may represent sound. Modulation and change. Aren't going to be exactly the same. Audio has varying volumes.

Over time and space Amplitude attenuation is not related to Speed of waves is constant. It has nothing to do with power. (same with sound energy) Speed and power are not the same. Power is independent of. Title: Chapter 2: Modulation 1 Chapter 2 Modulation 2 Communication System Chart 3 Introduction What is modulation.

Modulation is defined as the process of modifying a carrier wave (radio wave) systematically by the modulating signal (audio) This process makes the signal suitable for the transmission and compatible with the channel. In order to avoid AR in HID lamps, several methods have been proposed, such as square wave supply[12], pulse operation[13], extra-high frequency[14], frequency or amplitude modulation[For a 40 kHz sound wave, the maximum measurable range using phase shift is only mm.

In the present work, to enhance the measurable range to m, the ultrasonic signal is amplitude modulated by a 50 Hz signal, which is more appropriate for mobile robot localization and navigation in indoor by: 2.Automatic detection go2MONITOR; Antennas.

Broadcast AM Amplitude Modulation is vertically polarized. However, at HF High Frequency ( MHz) and lower frequencies signal bounce may allow horizontally polarized antennas to pick up signals as well. Aviation AM Amplitude Modulation is vertically polarized. Video ExamplesLocation: Worldwide.