Load pull

Load pull and Source pull are the processes of altering (pulling) the impedances at the output and input respectively of an RF device or component whilst measuring the device behaviour. This can be necessary when the device under test has a non-linear response. Harmonic load pull is load pull where the impedances at the harmonic frequencies are changed individually.

Load pull measurements are particularly useful for characterisation of amplifiers under large signal conditions, far from 50 Ω or the nominal line impedance.