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noise of PS 5243A to high

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noise of PS 5243A to high

Postby egonotto » Sun Mar 15, 2015 2:28 pm

PS5243A_15_noise.jpg
15 Bit
PS5243A_8_noise.jpg
8 Bit
Hello,
the noise of my PS 5243A 100MHz seems to be to high:

Bit AC RMS Peak To Peak
8 .... 263uV _ 1.13mV ___ > 120uV
12 .. 107uV _ 1.04mV
14 .. 115uv _ 1.11mV ____ > 100uV
15 .. 106uV _ 1.02mV ____ > 85uV
16 .. 85uV __ 0.810mV ___ > 70uV

I use: PicoScope® 6 - PC Oscilloscope software version: 6.10.11.15

Model: PicoScope 5243A
USB Version: 2,0
Calibration Date: Montag, 10. März 2014
Hardware Version: 1
Driver Version: 1.1.4.20
Firmware Version: 1.3.3.0 / 1.0.24.0

Best Regards
egonotto
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Re: noise of PS 5243A to high

Postby AndrewA » Wed Mar 25, 2015 3:16 pm

Hello Egonotto,

What noise level are you expecting? Is there anything connected to the input?

Could you email into support@picotech.com a spectrum plot data file with scale in dBu, for this issue. (15 bit vs 8 bit)
To create a psdata file-
Go to ‘File’ menu -> ‘save’ -> enter file name (file type should be set on psdata)

Regards Andrew
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Regards Andrew
Technical Specialist
AndrewA
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Re: noise of PS 5243A to high

Postby egonotto » Sat Mar 28, 2015 2:51 am

Hello Andrew,

thanks for your answer.
I compare my data with the specification in the datasheet:

"Noise (on 50 mV range) 8-bit mode 120 μV RMS • 12-bit mode 110 μV RMS • 14-bit mode 100 μV RMS •15-bit mode 85 μV RMS • 16-bit mode 70 μV RMS".

This is valid also for the scopes with 200MHz bandwidth.

As my scope is a 100MHz bandwidth the noise should even be lower.
The peak to peak noise is about 10 times larger.

Yet with the noise data in the datasheet one can ask whether 14Bit till 16Bit makes sense.

In my experience 14Bit and more brings not much accord to 12Bit.

I test the noise with open inputs and with 50Ohm. It is no much difference

Only with lowpass filter the data with 50Ohm becoming substantial better than with open inputs. Presumably a good part of the noise comes from the higher frequency.
In 8Bit mode the cannel A has much higher noise than the cannel B in RMS. (250 uV against 100uV)
Peak to peak is cannel A not worse than channel B.

I will this mail with the requested file to support@picotech.com

Best Regards
egonotto
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