a method for emission testing of a semiconductor device , by mounting the dut onto an test bench of an emission tester , the emission tester having an optical detector ; electrically connecting the dut to an electrical tester ; applying electrical test signals to the dut while keeping test parameters constant ; serially inserting one of a plurality of shortpass filters into an optical path of the emission tester and collecting emission test signal from the optical detector until all available shortpass filters have been inserted into the optical path ; determining appropriate shortpass filter providing highest signal to noise ratio of the emission signal ; inserting the appropriate shortpass filter into the optical path ; and , performing emission testing on the dut .