doubler

from WordNet (r) 3.0 (2006)

doubler
    n 1: an electronic device that doubles the voltage or the
         frequency of an input signal

from The Collaborative International Dictionary of English v.0.48

Doubler \Dou"bler\, n.
   1. One who, or that which, doubles.
      [1913 Webster]

   2. (Elec.) An instrument for augmenting a very small quantity
      of electricity, so as to render it manifest by sparks or
      the electroscope.
      [1913 Webster]

   3. A part of a distilling apparatus for intercepting the
      heavier fractions and returning them to be redistilled.
      [Webster 1913 Suppl.]

   4. (Calico Printing) A blanket or felt placed between the
      fabric and the printing table or cylinder.
      [Webster 1913 Suppl.]