Decibels for acoustic applications are always positive numbers,
basically because the log of the ratio is intensity (W/m^2) to a very
small reference intensity (10^-12 W/m^2) and ambient sound is always
greater than this reference so the ln is positive.
I'm a little confused about what ratio of reference power or voltage is
used in electronics/engineering (where the dB scale is usually a set of
negative numbers). In particular, electrical engineers seem to come up
with this negative scale even when the circuit is measuring input from a
microphone. Can anyone point me to a reference that makes the connection
between the acoustic scale and the electrical engineering scale?
kyle
--
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Scientists are like 'mariners who have to
rebuild their ship on the high seas, without
ever being able to strip it down in dock and
construct it afresh from the best available
components' Otto Neurath