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My university owns a Teseq NSG4070-35 conducted immunity measurement unit, including a 6dB attentuator and M3-CDN.

In the handbook and datasheet of the device it says that the power meter is sensitive and can be damaged above 27dBm. However, when one calibrates the test scenario for EN 61000-4-6, the power meter measures the signal coming from the AE-Port of the CDN that is connected via the attentuator to the amp out port of the NSG4070-35.

Access to datasheet: http://www.teseq.com/products/NSG-4070.php, under downloads

I have calibrated the device successfully for low voltages, but now i would like to test it for 30V conducted immunity. In the calculation of test levels, it says that the voltage levels at U=30V are 1/6 of the test levels, meaning 5V which calculates to 26.95dBm in a 50 Ohm system. In the datasheet, it says that the power meter input should not exceed 27dBm, the absolute maximum rating is 28dBm. Can anyone tell me if another attentuator is needed or if i am fine? What i don't get is that a 6dB attentuator is used anyway, so i should not come close right? And in the datasheet it is said, that the NSG4050 in varaint -35 can only measure levels of up to 19V with a CDN. If that is the case, can the power meter input still be destroyed?

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  • \$\begingroup\$ You are trying to test the immunity of your EUT not the damage level of your power meter. So a power splitter and attenuator makes more sense to ensure you stay far away from the limits going into your power meter. (<<27dBm or 13Vpp e.g. keep <20dBm or 100mW) These are pretty high power levels for a true RMS power sensor and using a splitter allows one to use ratios if needed to measure the results . \$\endgroup\$ – Sunnyskyguy EE75 Jan 13 '17 at 18:54
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Well you could calculate or experiment. Why don't you error on the side of caution and throw a couple of attenutators in and then measure the signal? If the signal is still in range then remove the attenuators one at a time until you get your signal in the desirable range.

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