A test system and method which employs a filter bank to select different spectral components of a pulsed measurement signal. The filter bank utilizes filter nulls to suppress non-selected spectral components. After filtering the selected spectral components, the spectral components are combined to provide for a measurement signal which is analyzed to determine characteristics of a device being tested. The characteristics of the filters can be adjusted in response to a change in the characteristics of a pulsed signal applied to the device under test, so that the selected spectral components will correspond to desired spectral components generated by the pulsed signal applied to the device under test.