Introduction - If you have any usage issues, please Google them yourself
Most audio equipment testing is done on a stimulus-response basis. A signal
of known characteristics is fed to the input of the device under test (DUT) and
the output of the DUT is measured. The performance of the DUT is determined
by degradation of the output signal from the known input signal. Often,
sets of measurements are made as the stimulus is swept or stepped across the
frequency spectrum or across an amplitude range, and the desired performance
information is determined by the relationship between the corresponding set of
output measurements.