"SteveB" wrote in message
news:OTrWd.161$qf7.129@fed1read03...
What is the name for the electronic device that measures decibel levels?

Steve



This is not a question with an easy answer. The decibel is a relative
measure, i.e., it is the ratio of two power levels expressed as a logrithm
(dB = 10 log P1/P2). Sometimes, sound levels are measured in decibels
referenced to the threshold of audibility. Commonly, radio frequency power
is expressed in decibels referenced to a milliwatt (dBm) or to a watt (dBW).
Antenna gain is expressed in dB referenced to the performance of an
isotropic antenna. If the impedences are constant, since P = E squared /
Z, decibels can express the ratio of two voltages (dB = 20 log E1/E2).
Hence, the signal level into a receiver is often expressed as decibels
referenced to a microvolt (dBuv). The list goes on and on...

And a wide variety of instruments are used to make the various measurements.

Jerry