I am going to assemble a FMR system but I'm having problem in detect the signal from sample as these are of very low amplitudes. Can you please suggest some ways to measure these low varying signals from the noisy environment? Can you suggest other ways than looking for amplifiers as these are very costly?
Dear Vinay
Apart from the requirement of measuring equipment, for the measurements of such a small signal you need electromagnetic shielding of the test specimen. For this purpose you have to mount your sample in metallic sample holder with a very high vacuum inside. Proper shielded cable connections have to be used from sample holder to the instrument. Feedthroughs used in the sample holder should be highly insulating. I hope you might be taking care of these points in your experimental set up. As far as the instrument is concerned, you can use Keithley nanovoltmeters or of some other reputed manufacturer.
Check lock-in amplifiers (e.g. thinksrs.com, SR850) - they are able to measure AC signals in micro- and and nano-volts range. But it comes at a price, measuring such small voltages is not an easy task.
My Dear Vinay Sharma ji; Please go through the following links or references. May be useful in your research. Good luck.
http://www.eevblog.com/forum/testgear/measuring-nanovolts/
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4313620
Dear Vinay,
To measure low voltages in the order of nanovolts, you need clearly a precise nanovoltmeter. I send you here attached the reference of two most popular equipment from Keithley and Keysight (formerly Agilent) companies. But you could try to find other similar ones.
In addition you need pay attention to a good electromagnetic shielding of you sample. If possible put your complete holder inside a Faraday Box that you may design according to your needs, in order to isolate it from any electromagnetic interferenc, and connect it to the ground of the measurement equipment. Place your meqsurement equipment as close as possible of you holder, and eventually inside of another Faraday Box (if your environment is very electromanetic-noisy). Finally, all your connecting electrical wires must be also shielded, use coaxial wires for this purpose.
With these considerations, you should be able to measure low voltages with resolution of about 2nV (1nV is the resolution of the Keithley in channel 1 with some filters, and 1.3 nV is the noise of the Keysight, I send you also the specifications sheets)
I hope this could be useful for you. Best regards.
I have the same problem, and what‘s worse, the voltage signal I want to detect is generated by alternating electromagnetic field. Do you have any idea. Thank you!
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