incorrect unit label on PSD and FFT

[hubmayr]

Units are listed as mV^2/Hz or mV/sqrt{Hz}, but they are in fact micro Volts.

[ggggggggg]

This could be an error on the dastard size or the microscope side, microscope is more likely.

[hubmayr]

not sure if this is definitive, but writing my own script using easy client does extract microvolts. Since that uses dastard, doesn't that mean microscope is the problem?

…

On Thu, Jan 14, 2021 at 3:56 PM ggggggggg ***@***.***> wrote: This could be an error on the dastard size or the microscope side, microscope is more likely. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#225 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AESEKDIW3QZDVWTTQ6FKCQLSZ5ZANANCNFSM4WBRDCDA> .

[ggggggggg]

Probably, there place it could be

1. dastard sends out info about what the physical units are
2. microscope could make a mistake with that info

My guess is #2.

[joefowler]

Hey @hubmayr. I am finally looking into this, and I cannot find the problem. Unfortunately, I'm not looking at any data where I know the physical power spectrum level. But I am looking at data where I am interpreting 65536 arbs = 1 Volt, or 1 arb = 15.3 µV. When I see a spectrum peaking at 13172 arbs/sqrt(Hz), it comes to 201 mV/sqrt(Hz). That all looks right to me.

So although I guessed (like Galen) that microscope was probably at fault, now I'm not so sure. Is that assumption 1 V = 2^16 arbs wrong for your case?