Abstract In this paper, we describe the difference between oscilloscope pulsing tests and waveform generator fast measurement unit (WGFMU) tests in analyzing high-resistance defects in DRAM main cells. Nanoprobe systems have various constraints in terms of pulsing whether it involves an oscilloscope or pulse generator. There are certain types of devices, such as DRAM cells, for which these systems are ineffective because saturation currents are too small. In this paper, we address this constraint and propose a new way to conduct pulsing tests using the WGFMU's arbitrary linear waveform generator in combination with an electro-optical nanoprobe.