attenuators can be designed to have either equal or
unequal impedances and to provide any amount of
attenuation (theoretically) equal to or greater than
the configuration's minimum attenuation - depending
on the ratio of Z1/Z2.
Attenuators with equal terminations have a minimum
attenuation of 0 dB. Unequal terminations place a
lower limit on the attenuation.
power in / power out, or in decibels = 10 * log (K)
or in decibels KMIN
= 10 * log (Kmin) dB