A polishing apparatus of the present invention comprises an amplifier for amplifying a first signal being input from the vibration detecting device attached on a second surface plate to then output a second signal, a gain indicator for determining unsuitableness of a gain of the amplifier based on a...http://www.google.se/patents/US5876265?utm_source=gb-gplus-sharePatent US5876265 - End point polishing apparatus and polishing method
