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A graph of amplitude vs frequency (not time) for a single sinusoid at frequency 0.6 f s and some of its aliases at 0.4 f s, 1.4 f s, and 1.6 f s would look like the 4 black dots in Fig.3. The red lines depict the paths ( loci ) of the 4 dots if we were to adjust the frequency and amplitude of the sinusoid along the solid red segment (between f ...
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light).The opposite change, a decrease in wavelength and increase in frequency and energy, is known as a blueshift, or negative redshift.
Stationary sound source produces sound waves at a constant frequency f, and the wave-fronts propagate symmetrically away from the source at a constant speed c. The distance between wave-fronts is the wavelength. All observers will hear the same frequency, which will be equal to the actual frequency of the source where f = f 0.
Frequency dispersion of surface gravity waves on deep water. The red square moves with the phase velocity, and the green dots propagate with the group velocity. In this deep-water case, the phase velocity is twice the group velocity. The red square traverses the figure in the time it takes the green dot to traverse half.
A linear chirp waveform; a sinusoidal wave that increases in frequency linearly over time. A chirp is a signal in which the frequency increases (up-chirp) or decreases (down-chirp) with time. In some sources, the term chirp is used interchangeably with sweep signal. [1]
A modulated wave resulting from adding two sine waves of identical amplitude and nearly identical wavelength and frequency. A common situation resulting in an envelope function in both space x and time t is the superposition of two waves of almost the same wavelength and frequency: [2]
As can be seen in the animation, the group moves with a group velocity c g different from the phase velocity c p, due to frequency dispersion. The group velocity is depicted by the red lines (marked B) in the two figures above. In shallow water, the group velocity is equal to the shallow-water phase velocity. This is because shallow water waves ...
Using this frequency, the Bode phase plot finds the phase of βA OL. If the phase of βA OL (f 0 dB) > −180°, the instability condition cannot be met at any frequency (because its magnitude is going to be < 1 when f = f 180), and the distance of the phase at f 0 dB in degrees above −180° is called the phase margin.