Complex sentence: To achieve high accuracy, the test instrument and its probe must not significantly affect the voltage being measured; this is accomplished by ensuring that the combination of instrument and probe exhibit a sufficiently high impedance that will not load the DUT.
Split into simpler sentences: To achieve high accuracy, the test instrument and its probe must not significantly affect the voltage being measured. This is accomplished by ensuring that the combination of instrument and probe exhibit a sufficiently high impedance that will not load the DUT.