![]() ![]() ![]() In electronics, the gains of amplifiers, attenuation of signals, and signal-to-noise ratios are often expressed in decibels. Instead, the decibel is used for a wide variety of measurements in science and engineering, most prominently for sound power in acoustics, in electronics and control theory. The bel was named in honor of Alexander Graham Bell, but the bel is seldom used. The definition of the decibel originated in the measurement of transmission loss and power in telephony of the early 20th century in the Bell System in the United States. The decibel scales differ by a factor of two, so that the related power and root-power levels change by the same value in linear systems, where power is proportional to the square of amplitude. When expressing root-power quantities, a change in amplitude by a factor of 10 corresponds to a 20 dB change in level. On the decibel scale, 0 dB is the smallest audible sound. This scale is called the decibel scale or dB scale. Therefore, a logarithmic scale is used to express sound levels meaningfully in more flexible numbers rather than a linear one. That is, a change in power by a factor of 10 corresponds to a 10 dB change in level. What is the Decibel Scale The human ear has the ability to handle an immense range of different sound levels. Because the decibel scale is logarithmic, it changes by an additive constant when the intensity as measured in W/m2 changes by a multiplicative factor. When expressing a power ratio, it is defined as ten times the logarithm in base 10. The decibel scale is a logarithmic scale for measuring the sound intensity level. Two principal types of scaling of the decibel are in common use. For example, for the reference value of 1 volt, a common suffix is " V" (e.g., "20 dBV"). In the latter case, the numeric value expresses the ratio of a value to a fixed reference value when used in this way, the unit symbol is often suffixed with letter codes that indicate the reference value. The unit expresses a relative change or an absolute value. ![]() You can interpret a signal-to-noise ratio of 50 dB in terms of. And with decibel scaling, the geometric differences among physical values (the physical ratios) are transformed into arithmetic differences. Logarithmic unit expressing the ratio of physical quantities Logarithmic scaling pushes large values closer together and spreads small values further apart. ![]()
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