DecibelThe decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10 (approximately 1.26) or root-power ratio of 10 (approximately 1.12). The strict original usage above only expresses a relative change.Level (logarithmic quantity)In science and engineering, a power level and a field level (also called a root-power level) are logarithmic magnitudes of certain quantities referenced to a standard reference value of the same type. A power level is a logarithmic quantity used to measure power, power density or sometimes energy, with commonly used unit decibel (dB).
Signal-to-noise ratioSignal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power, often expressed in decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise.
Logarithmic scaleA logarithmic scale (or log scale) is a method used to display numerical data that spans a broad range of values, especially when there are significant differences among the magnitudes of the numbers involved.
Power (physics)Power is the amount of energy transferred or converted per unit time. In the International System of Units, the unit of power is the watt (symbol W), equal to one joule per second (J/s). Power is a scalar quantity. The output power of a motor is the product of the torque that the motor generates and the angular velocity of its output shaft.
Electrical impedanceIn electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of the sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. In general, it depends upon the frequency of the sinusoidal voltage.
International System of UnitsThe International System of Units, internationally known by the abbreviation SI (from its official French name, Système international d'unités), is the modern form of the metric system and the world's most widely used system of measurement. It is the only system of measurement with official status in nearly every country in the world, employed in science, technology, industry, and everyday commerce.
Free-space path lossIn telecommunications, the free-space path loss (FSPL) (also known as free-space loss, FSL) is the decrease in signal strength of a signal traveling between two antennas on a line-of-sight path through free space, which occurs because the signal spreads out as it propagates. The "Standard Definitions of Terms for Antennas", IEEE Std 145-1993, defines free-space loss as "The loss between two isotropic radiators in free space, expressed as a power ratio."
Decibel wattThe decibel watt (dBW or dBW) 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.
WattThe watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m⋅s. It is used to quantify the rate of energy transfer. The watt is named in honor of James Watt (1736–1819), an 18th-century Scottishinventor, mechanical engineer, and chemist who in 1776 improved the Newcomen engine with his own steam engine, which became fundamental for the Industrial Revolution.
Dimensionless quantityDimensionless quantities, or quantities of dimension one, are quantities with no associated units of measurement. These may be ratios of quantities with the same physical units or ratios of dimensionally equal products with identical units. For instance, alcohol by volume (ABV) represents a volumetric ratio; its value remains independent of the specific units of volume used, such as in milliliters per milliliter (mL/mL).*As an Amazon Associate I earn from qualifying purchases.