7.3.8 EMIRR +IN Test Configuration

Figure 45 shows the circuit configuration for testing the EMIRR IN+. An RF source is connected to the op amp noninverting input pin using a transmission line. The op amp is configured in a unity-gain buffer topology with the output connected to a low-pass filter (LPF) and a digital multimeter (DMM). A large impedance mismatch at the op amp input causes a voltage reflection; however, this effect is characterized and accounted for when determining the EMIRR IN+. The resulting DC offset voltage is sampled and measured by the multimeter. The LPF isolates the multimeter from residual RF signals that may interfere with multimeter accuracy.

Figure 45. EMIRR +IN Test Configuration