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Oscilloscope input noise comparison
Andreas:
Hello,
and a 16 Bit noise measurement with .csv data (had to split it into 2 parts)
Again 2mV/Div 62.5 MS/s maximum sample rate in 16 Bit mode and with 20 MHz hardware bandwidth limiter.
Further Pictures:
Software low pass with 1 MHz, 50kHz, 1kHz additional to the 20 MHz.
and 20 Bit enhanced resolution out of 20 MHz.
with best regards
Andreas
Andreas:
Hello,
and again 16 Bit values, this time without bandwidth limit.
the 16 Bit values are only 625000 samples because of upload limit.
with best regards
Andreas
David Hess:
--- Quote from: Hagrid on October 30, 2018, 07:18:59 pm ---Thanks a lot! I was looking for exactly this data. Please someone correct me if I am wrong, but is the noise of the 5444 about five to ten times higher than the noise from the cheap Chinese scopes from the first page?
This makes little sense to me, since it has modes up to 16 bit resolution.
I would really appreciate it if somebody could explain this to me, thanks :).
--- End quote ---
The Picoscope details I have seen show an integrated CMOS transimpedance buffer intended for DSOs from TI that by itself has 100 times the noise of a discrete front end at low frequencies. I mean literally 1000nV/SqrtHz where a discrete design could be 10nV/SqrtHz.
So a broadband RMS noise of 125.7uV over 200MHz does not surprise me at all and that is about 5 times worse than my 40+ year old 200MHz analog oscilloscopes.
Hagrid:
Thank you all for sharing this Information.
--- Quote from: David Hess on November 01, 2018, 12:44:50 am ---
--- Quote from: Hagrid on October 30, 2018, 07:18:59 pm ---Thanks a lot! I was looking for exactly this data. Please someone correct me if I am wrong, but is the noise of the 5444 about five to ten times higher than the noise from the cheap Chinese scopes from the first page?
This makes little sense to me, since it has modes up to 16 bit resolution.
I would really appreciate it if somebody could explain this to me, thanks :).
--- End quote ---
The Picoscope details I have seen show an integrated CMOS transimpedance buffer intended for DSOs from TI that by itself has 100 times the noise of a discrete front end at low frequencies. I mean literally 1000nV/SqrtHz where a discrete design could be 10nV/SqrtHz.
So a broadband RMS noise of 125.7uV over 200MHz does not surprise me at all and that is about 5 times worse than my 40+ year old 200MHz analog oscilloscopes.
--- End quote ---
Very interesting. I really wonder why they made this design decision. In my opinion it looks like this contradics the whole purpose of a high resolution mode.
MrW0lf:
--- Quote from: Hagrid on November 01, 2018, 09:35:46 am ---Very interesting. I really wonder why they made this design decision. In my opinion it looks like this contradics the whole purpose of a high resolution mode.
--- End quote ---
Maybe it's related to their main business background - automotive. High resolution is not only for looking at very low voltages. Would be useful with x100 probe etc.
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