U : Sound and Vibration Terms, Definitions, Units, Measurements ...
UKAS : United Kingdom Accreditation Service is the national accreditation body recognized by government to assess, against internationally agreed standards, ...
UK Government Environmental Noise Regulations
Aircraft Noise indicators,
Industrial Noise and Port Noise indicators,
Railway Noise indicators,
Road Traffic Noise indicators,
Ultrasound Definition IEC 801-21-04,
whose frequency is above the high-frequency limit of audible sound (about 16 kHz)
Undamped Natural Frequency
the natural frequency of a structure.
Undamped Natural Frequency Definition IEC 801-24-09, frequency of free oscillation resulting from only elastic and inertial forces of the system.
See also natural frequency
the input to the sound level meter is too low for the current measurement range.
Under-range % percentage of time that an under range occurred.
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