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Scientific pitch, also known as philosophical pitch, Sauveur pitch or Verdi tuning, is an absolute concert pitch standard which is based on middle C (C 4) being set to 256 Hz rather than approximately 261.63 Hz, [1] making it approximately 31.77 cents lower than the common A440 pitch standard.
Crystal oscillators can be manufactured for oscillation over a wide range of frequencies, from a few kilohertz up to several hundred megahertz.Many applications call for a crystal oscillator frequency conveniently related to some other desired frequency, so hundreds of standard crystal frequencies are made in large quantities and stocked by electronics distributors.
Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals , radio waves, and light. For example, if a heart beats at a frequency of 120 times per minute (2 hertz), the period—the time interval between beats—is half a second (60 ...
[4] [5] In addition, in non-centrosymmetric crystals belonging to crystallographic point group 432, SHG is not possible [6] and under Kleinman's conditions SHG in 422 and 622 point groups should vanish, [7] although some exceptions exist. [8] In some cases, almost 100% of the light energy can be converted to the second-harmonic frequency.
Frequency allocation (or spectrum allocation) is the part of spectrum management dealing with the designation and regulation of the electromagnetic spectrum into frequency bands, normally done by governments in most countries. [1]
As a matter of convention, the ITU divides the radio spectrum into 12 bands, each beginning at a wavelength which is a power of ten (10 n) metres, with corresponding frequency of 3×10 8−n hertz, and each covering a decade of frequency or wavelength. Each of these bands has a traditional name.
The information in the specific section Concert_pitch#Controversial_claims_for_432_Hz first redirected to was not a good representation of the subject. 432 Hz is not only a controversial claim, but also has uncontroversial historical use. Much more info on explicitly 432 Hz exist in both articles Concert pitch and Scientific pitch.
Spectrum management is a growing problem due to the growing number of spectrum uses. [6] Uses include: over-the-air broadcasting, (which started in 1920); government and research uses (which include defense, public safety—maritime, air, police—resource management, transport, and radio astronomy); commercial services to the public (including voice, data, home networking); and industrial ...