In this section we will focus on measuring OIP3 of designed measuring kit. Own OIP3 we need to know so that we can assess the suitability of the kit for measuring IMD of external passive circuits (BPF, LPF, HPF for example) with higher IP3.
During first measurement I used ferrite binocular FB-43-2402 with 8 turns bifilar in the combiner. OIP3 was measured at different levels of the output signal (from 0 to +22dBm). The following picture shows OIP3 dependence on the output signal level.