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  2. Numeric precision in Microsoft Excel - Wikipedia

    en.wikipedia.org/wiki/Numeric_precision_in...

    Excel graph of the difference between two evaluations of the smallest root of a quadratic: direct evaluation using the quadratic formula (accurate at smaller b) and an approximation for widely spaced roots (accurate for larger b). The difference reaches a minimum at the large dots, and round-off causes squiggles in the curves beyond this minimum.

  3. Signal strength in telecommunications - Wikipedia

    en.wikipedia.org/wiki/Signal_strength_in...

    High-powered transmissions, such as those used in broadcasting, are expressed in dB-millivolts per metre (dBmV/m). For very low-power systems, such as mobile phones, signal strength is usually expressed in dB-microvolts per metre (dBμV/m) or in decibels above a reference level of one milliwatt .

  4. Effective radiated power - Wikipedia

    en.wikipedia.org/wiki/Effective_radiated_power

    The ideal dipole antenna could be further replaced by an isotropic radiator (a purely mathematical device which cannot exist in the real world), and the receiver cannot know the difference so long as the input power is increased by 2.15 dB. The distinction between dB d and dB i is often left unstated and the reader is sometimes forced to infer ...

  5. Gain (antenna) - Wikipedia

    en.wikipedia.org/wiki/Gain_(antenna)

    Since a lossless dipole antenna has a gain of 2.15 dBi, the relation between these units is () (). For a given frequency, the antenna's effective area is proportional to the gain. An antenna's effective length is proportional to the square root of the antenna's gain for a particular frequency and radiation resistance .

  6. Directivity - Wikipedia

    en.wikipedia.org/wiki/Directivity

    The actual result is 34.6380 dBi, just shy of the ideal 35.0745 dBi we expected. [7] Why the difference from the ideal? If the spacing in the x and y dimensions is λ {\displaystyle \lambda } , then the spacing along the diagonals is λ 2 {\displaystyle \lambda {\sqrt {2}}} , thus creating tiny regions in the overall array where photons are ...

  7. dBc - Wikipedia

    en.wikipedia.org/wiki/DBc

    dBc (decibels relative to the carrier) is the power ratio of a signal to a carrier signal, expressed in decibels.For example, phase noise is expressed in dBc/Hz at a given frequency offset from the carrier. dBc can also be used as a measurement of Spurious-Free Dynamic Range between the desired signal and unwanted spurious outputs resulting from the use of signal converters such as a digital ...

  8. Directional antenna - Wikipedia

    en.wikipedia.org/wiki/Directional_antenna

    Patch antenna gain pattern. A directional antenna or beam antenna is an antenna which radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain direction is desired, or in receiving antennas receive radio waves from one specific direction only.

  9. Decibel watt - Wikipedia

    en.wikipedia.org/wiki/Decibel_watt

    The decibel watt (dBW or dB W) is a unit for the measurement of the strength of a signal expressed in decibels relative to one watt.It is used because of its capability to express both very large and very small values of power in a short range of number; e.g., 1 milliwatt = −30 dBW, 1 watt = 0 dBW, 10 watts = 10 dBW, 100 watts = 20 dBW, and 1,000,000 W = 60 dBW.