| 摘要 |
In a method of testing electrical equipment having inherent stray impedances whilst the equipment is connected to a conductor a swept sinusoidal signal is injected and the response of the equipment to the signal analysed. In order to prevent current flow within the conductor affecting the results of the analysis a nulling signal is injected to nullify the current which would otherwise flow in the conductor as a result of the application of the swept-frequency signal. In a preferred embodiment the phase and amplitude of currents in the conductor and in the line through which nulling signals are injected are compared. The phase and amplitude of the nulling signal are adjusted in accordance with the result of these comparisons. |
