Operator::dB
Operator to support decibel (dB) arithmetic.
use Operator::dB;
put 100 + 3dB;
# 199.52623149688796
put 100 - 3dB;
# 50.11872336272723
put 10dB + 20dB;
# 20.413927dB
Description
The interface tries to be intuitive while avoiding ambiguity. For example, the following makes sense (adding 3dB is approximately equivalent to doubling).
10 + 3dB
# 19.952623149688794
But the following doesn't make sense. It could represent either 13dB or
10.8dB (i.e. 3dB + 10dB).
3dB + 10 # DOESN'T WORK!
All supported operations are discussed in the following subsections.
Addition and subtraction on numbers
Adding or subtracting decibel values to and from numbers (of Numeric type)
scales the number by the corresponding decibel gain:
put 100 + 3dB;
# 199.52623149688796
put 100 - 3dB;
# 50.11872336272723
Addition and subtraction on decibels
Decibels can be added to, or subtracted from, each other.
This type of operation returns an Operator::dB::Decibel wrapper object:
my $foo = 3dB + 2dB - 1dB;
# Operator::dB::Decibel.new(x => 10, y => 0.365...)
You can get the decibel value itself with .dB:
$foo.dB;
# 3.6571819272302735
Or by stringification:
"The gain is: $foo";
# The gain is: 3.657182dB
Or by defining your own format with .fmt:
$foo.fmt("%.1f dB(A)");
# 3.7 dB(A)
Caveats
This package exports overloads to built-in operators, which is potentially
reckless. But the operator signatures all contain at least one
Operator::dB::Decibel object (which is not built-in), so it should be
fine!
The Num method is not implemented on the wrapper class, so many built-in
numerical operations don't work, e.g. 1dB * 1. This is a necessary
limitation because decibel arithmetic is only semantically valid for addition
and subtraction AFAIK.