Search results
Results from the WOW.Com Content Network
Frequency-dependent attenuation of electromagnetic radiation in standard atmosphere In many cases, attenuation is an exponential function of the path length through the medium. In optics and in chemical spectroscopy , this is known as the Beer–Lambert law .
In telecommunications, the free-space path loss (FSPL) (also known as free-space loss, FSL) is the attenuation of radio energy between the feedpoints of two antennas that results from the combination of the receiving antenna's capture area plus the obstacle-free, line-of-sight (LoS) path through free space (usually air). [1]
The attenuation coefficient of a volume, denoted μ, is defined as [6] =, where Φ e is the radiant flux;; z is the path length of the beam.; Note that for an attenuation coefficient which does not vary with z, this equation is solved along a line from =0 to as:
Path loss, or path attenuation, is the reduction in power density (attenuation) of an electromagnetic wave as it propagates through space. [1] Path loss is a major component in the analysis and design of the link budget of a telecommunication system. This term is commonly used in wireless communications and signal propagation.
It turns out that instead of measuring scattered energy versus angle, as with light, in the case of ultrasound, measuring the transmitted energy versus frequency is a better choice. The resulting ultrasound attenuation frequency spectra are the raw data for calculating particle size distribution.
It is possible to extrapolate the cumulative attenuation distribution at a given location by using the CCIR interpolation formula: [12] A p = A 001 0.12 p −(0.546 − 0.0043 log 10 p). where A p is the attenuation in dB exceeded for a p percentage of the time and A 001 is the attenuation exceeded for 0.01% of the time.
mass attenuation coefficient, also called mass extinction coefficient, is the attenuation coefficient divided by density; see mass attenuation coefficient for details; absorption cross section and scattering cross section are both quantitatively related to the attenuation coefficient; see absorption cross section and scattering cross section ...
is the passband attenuation ripple in dB (.05 dB, 1 dB, etc.)). is the desired passband attenuation at the cutoff frequency in dB (1 dB, 3 dB, 10 dB, etc.) is the number of poles (the order of the filter).