Many lamps emit radio noise which can be heard by humans and detected by modern digital electronics. Lamps and lighting in general are normally (in laboratories and commercial businesses) connected on separate, isolated circuits from all wall outlets. This makes it easier to maintain the circuits and reduce noise from other circuits being passed on the same lines. Wall outlets are also often setup as separate, isolated circuits (set up in groups, just like the lights) too. You probably have your instrument on the same circuit as the lighting. Connect it to a dedicated, isolated circuit and the problem should go away.

UPS: If you have a UPS connected to your instrument, then a poorly selected UPS can also contribute to noise on the circuit, or worse (early failure of the system). Make sure you only purchase and use UPS systems which output PURE SINEWAVE energy, not square waves or pseudo-sine wave outputs found on the cheap UPS systems.For more info on selecting a UPS for use with high-end lab instruments, please read the linked article; "Power and Surge Protection for Computers & Analytical Instruments (e.g. Uninterruptible Power Supply AKA UPS)".

Note: For your safety, please have a license professional electrician check all circuits you are using for both safety and to determine which circuit can be isolated from the lighting.

http://hplctips.blogspot.com/2011/05/power-and-surge-protection-for.html

Hello.

I do not think this is related to the reason. It may be due to lack of a stabilizer.

Hello, 

was also thinking of using a stabilizer to suppress this issue. There are some good answers given by Prof. Nebi Caka on this topic:

https://www.researchgate.net/profile/Nebi_Caka

Link to replies from him on stabilizers:

https://www.researchgate.net/post/What_is_the_difference_between_a_regulator_and_stabilizer

https://www.researchgate.net/post/What_is_the_difference_between_a_regulator_and_stabilizer

https://www.researchgate.net/profile/Nebi_Caka