The transposed scanning system utilizes sinusoidal scanning to provide bi-directional scanning along a short axis of a display screen (31) of a cathode ray tube (30).

The sine sweep and cosine sweep together establish a complex input signal, whereby to each instant there is related a particular frequency.

The method comprises the steps of applying a sine sweep and a cosine sweep to an input of the DUT, and measuring response signals at an output of the DUT.

A signal of a predetermined amplitude obtained by sine-wave sweeping a range of 7.4 MHz-8.9 MHz by 140 Hz is sent out from a transmitting antenna (1).