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The decibel originates from methods used to quantify signal loss in telegraph and telephone circuits. Until the mid-1920s, the unit for loss was miles of standard cable (MSC). 1 MSC corresponded to the loss of power over one mile (approximately 1.6 km) of standard telephone cable at a frequency of 5000 radians per second (795.8 Hz), and matched closely the smallest attenuation detectable to a ...
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 ...
Measurement of transmission loss can be in terms of decibels. Mathematically, transmission loss is measured in dB scale and in general it can be defined using the following formula: TL = 10 log 10 | W i W t | {\displaystyle 10\log _{10}\left\vert {W_{i} \over W_{t}}\right\vert } dB
In engineering, attenuation is usually measured in units of decibels per unit length of medium (dB/cm, dB/km, etc.) and is represented by the attenuation coefficient of the medium in question. [1] Attenuation also occurs in earthquakes; when the seismic waves move farther away from the hypocenter, they grow smaller as they are attenuated by the ...
While 1 atm (194 dB peak or 191 dB SPL) [11] [12] is the largest pressure variation an undistorted sound wave can have in Earth's atmosphere (i. e., if the thermodynamic properties of the air are disregarded; in reality, the sound waves become progressively non-linear starting over 150 dB), larger sound waves can be present in other atmospheres ...
Noise figure (NF) and noise factor (F) are figures of merit that indicate degradation of the signal-to-noise ratio (SNR) that is caused by components in a signal chain.These figures of merit are used to evaluate the performance of an amplifier or a radio receiver, with lower values indicating better performance.
≈ 1 hour walk, Currently defined in US as 3 Statute miles, [3] but historically varied from 2 to 9 km ≈ 4828 m: light-day: ≡ 24 light-hours ≡ 2.590 206 837 12 × 10 13 m: light-hour: ≡ 60 light-minutes ≡ 1.079 252 8488 × 10 12 m: light-minute: ≡ 60 light-seconds ≡ 1.798 754 748 × 10 10 m: light-second: ≡ Distance light ...
Vinyl microgroove phonograph records typically yield 55-65 dB, though the first play of the higher-fidelity outer rings can achieve a dynamic range of 70 dB. [25] German magnetic tape in 1941 was reported to have had a dynamic range of 60 dB, [26] though modern-day restoration experts of such tapes note 45-50 dB as the observed dynamic range. [27]