I am curious if anyone has ever had measurement problems & determined if it was caused by proximity to a breaker box or other source of magnetic field.
My phase noise test station (Agilent E5505A system) does not seem to be peforming as consistently as it did in the past. Yes I have it calibrated periodically. Anyway its in the Agilent Rack and is sitting next to a sizeable (42 slot) breaker box. It's not doing anything overtly odd but just seems like it's not performing as well as it used to. Would appreciate the benefit of of the board experiences.
Thanks!
We have had similar issues that were caused by building modifications. Suggest you see if you are on an isolated line. Make sure nothing has been added on the line such as a copier. We ended up using a line conditioner as a temporary solution. Good luck.
Absolutely the system can be subjected to noise interference due to proximity, and I would say even in the event that the line is isolated. I suspect the above poster is an individual that is extremely well-experienced with the phase-noise systems (michthai). If it's who I think it is, I watched this individual experiment with a phase-noise system that was problematic, and singularly rule-out just about every probable/possible source of error one could think of. Incidentally Brian, were your problems found consistently at any particular frequencie(s)? I once assisted an individual who had a 334A set up to measure distortion on a fairly low audio carrier (<1KHz), and he described toiling for a period of days off and on over the measurement without being able to understand why his one frequency was so erratic, while the other test signals were crisp and clean. Immediately after I arrived at his bench, I noticed that he was working on a second item within about 2 feet of his distortion set-up. The second item was plugged into a variac. I powered down his second item and killed power to the variac, and then re-accomplished his distortion measurement. It was well-within tolerance as you may have guessed before reading this far. Perhaps one of the power supply fans in the sig-gen(s) or Spec-An in the Agilent system is laboring under the weight of too much dust and dirt/contamination and has begun loading down the console ground/introducing onto the line a kind of "swan's gasp" noise that is being transmitted. I know that probably sounds like an oversimplified explanation for the problem your having, but if your system was formerly behaving normally, and has gradually begun returning aberrational noise onto the sweep, then it makes sense that it would have to do with dust accumulation in the power supply fans of the console instrument suite. Also, people have a way of inadvertently bumping/disturbing hardlines and semi-flexible 3. 5 lines on the front of the system. Again, I know these sound like basic observations, but if you still have problems after switching out hardlines/softlines, or cleaning the existing system lines, then at least you know it wasn't a simple systematic "kink". Definitely. . . safeguard the front of the console at the end of the day, and keep the PS fans/screens clean like they were still new. And of course, michthai's suggestion in conjuntion should dramatically increase the probability that your system will again begin performing normally.
We had some problems at out lab and it was because a mini fridge was plugged into the same wall outlet. We also had a problem one time due to a cheap surge protector.