Transmission loss
| Sound measurements | |
|---|---|
Characteristic | Symbols |
| Sound pressure | p, SPL, LPA |
| Particle velocity | v, SVL |
| Particle displacement | δ |
| Sound intensity | I, SIL |
| Sound power | P, SWL, LWA |
| Sound energy | W |
| Sound energy density | w |
| Sound exposure | E, SEL |
| Acoustic impedance | Z |
| Audio frequency | AF |
| Transmission loss | TL |
Transmission loss (TL) in general describes the accumulated decrease in intensity of a waveform energy as a wave propagates outwards from a source, or as it propagates through a certain area or through a certain type of structure.
It is a terminology frequently used in radio communication, twisted pair systems (PTSN, Ethernet, etc), optics and acoustics.[1][2] Measures of TL are very important in the industry of acoustic devices such as mufflers and sonars.
Definition
[edit]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 = dB
where:
- is the power of incident wave coming towards a defined area (or structure);
- is the power of transmitted wave going away from the defined area (or structure).
Applications
[edit]Transmission loss may refer to a more specific concept in one of the fields below:
- Transmission loss in electrical engineering describes the decrease of electrical power along an electrical cable. The term has its origins in telephony.
- Transmission loss in duct acoustics describes the acoustic performances of a muffler like system.
- Transmission loss in room acoustics describes the decrease of sound intensity that is reduced by a wall or other structure at a given frequency.
- Transmission loss in underwater acoustics describes the decrease of sound intensity that is reduced by a bubble curtain or other damping structure at a given frequency. The same term is sometimes used to mean propagation loss, which is a measure of the reduction in sound intensity between the sound source and a receiver, defined as the difference between the source level and the sound pressure level at the receiver.[3]
Types
[edit]- Transmission loss types in fiber-optic communication include absorption loss, scattering loss, dispersion loss, radiation loss and coupling loss.[4][2]
- Transmission loss types in twisted pair transmission systems include conductor loss, dielectric loss as well as radiation loss.[5]
References
[edit]- ^ Norton, Kenneth A. (January 1953). "Transmission Loss in Radio Propagation". Proceedings of the IRE. 41 (1): 146–152. doi:10.1109/JRPROC.1953.274172. hdl:2027/mdp.39015077289554. ISSN 2162-6634. S2CID 51651739.
- ^ a b "The FOA Reference For Fiber Optics - Measuring Power in dB and dBm". www.thefoa.org. Retrieved 2023-04-21.
- ^ ISO 18405:2017 Underwater acoustics - Terminology (International Organization for Standardization, Geneva, 2017)
- ^ Sonali (2022-03-22). "What are the losses in Optical fiber?". Goseeko blog. Retrieved 2023-04-21.
- ^ "Twisted pair". qucs.sourceforge.net. Retrieved 2023-04-21.
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