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The pulse-repetition frequency (PRF) is the number of pulses of a repeating signal in a specific time unit. The term is used within a number of technical disciplines, notably radar. In radar, a radio signal of a particular carrier frequency is turned on and off; the term "frequency" refers to the carrier, while the PRF refers to the number of ...
Figure 3: A pulse reaching the end of the medium, the end point is fixed. The successive positions of the pulse is drawn black, red, green, blue, black, red, green. The final green curve is the initial curve of figure 4. Figure 4: The reflection of the pulse. The successive positions of the pulse is drawn green, blue, black, red, green, blue.
The group velocity of a collection of waves is defined as. vg=∂ω∂k.{\displaystyle v_{g}={\frac {\partial \omega }{\partial k}}.} When multiple sinusoidal waves are propagating together, the resultant superposition of the waves can result in an "envelope" wave as well as a "carrier" wave that lies inside the envelope.
The theory of the velocity of the transmission of the pulse through the circulation dates back to 1808 with the work of Thomas Young. [9] The relationship between pulse wave velocity (PWV) and arterial wall stiffness can be derived from Newton's second law of motion (=) applied to a small fluid element, where the force on the element equals the product of density (the mass per unit volume ...
The wave equation is a second-order linear partial differential equation for the description of waves or standing wave fields such as mechanical waves (e.g. water waves, sound waves and seismic waves) or electromagnetic waves (including light waves). It arises in fields like acoustics, electromagnetism, and fluid dynamics.
In mathematics, the root mean square (abbrev. RMS, RMS or rms) of a set of numbers is the square root of the set's mean square. 1 Given a set , its RMS is denoted as either or . The RMS is also known as the quadratic mean (denoted ), [ 2 ][ 3 ] a special case of the generalized mean. The RMS of a continuous function is denoted and can be ...
Signal velocity. The signal velocity is the speed at which a wave carries information. It describes how quickly a message can be communicated (using any particular method) between two separated parties. No signal velocity can exceed the speed of a light pulse in a vacuum (by special relativity). Signal velocity is usually equal to group ...
Mode locking is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, on the order of picoseconds (10 −12 s) or femtoseconds (10 −15 s). A laser operated in this way is sometimes referred to as a femtosecond laser, for example, in modern refractive surgery.