Below are the questions asked during the live event, along with their respective answers.

Q: Do the issues presented affect the transducer method of CS101?
A: A study is in progress regarding the use of the transducer method, but there is reason to assume that the same problem exists. The transducer is used on the measurement side of the test circuit, and the problem is associated with the injection side of the test circuit, so the transducer method should encounter the same problem.

Q: Did the amplifier variance show up in the calibration? How can I determine if my amplifier is working correctly?
A: The calibration did not indicate an issue. The problem appeared when the AC circuit was powered in the test configuration related to the transformer coupling of the power frequency (and harmonics) voltage from the secondary back to the primary and into the amplifier output circuitry.

Q: The IEC 61000-4-16 tests the signal lines in addition to power – can this method be used for signal lines in the military approval tests?
A: Signal line testing is not applicable to the military applications as a requirement. However, the issue with coupling can exist, and if this presents a risk, the IEC 61000-4-16 method can be applied as supplemental testing. The goal is to identify and mitigate risks before fielding multiple units subject to interference.

Q: Hello, we have encountered issues with the EUT (switch-mode power supply) when connected to the large inductance of the audio transformer (1mH inductance secondary coil). Our EUT operates fine with 50uH LISNs, but the large inductance of the audio transformer causes oscillations and instability that we are not able to dampen. The 1mH inductance of the audio transformer is a much higher line impedance than in typical applications for our EUT. Any advice?
A: It is feasible to switch to a capacitor coupling method for DC powered test items, selecting a capacitor value that presents less than ~5-ohms at the test frequency. For AC circuits, the lower test frequency range would couple the power frequency back to the amplifier so testing at frequencies above 5 kHz with capacitor coupling would work. For AC circuits at test frequencies less than 5 kHz, a programmable power source with modulation capability could be used to inject the interfering signal.