Noise levels

Topics about DSLogic as an oscilloscope
Hi,

I've just receive the oscilloscope and notice that there seems to be an extreme amount of noise. Is this expected?

In the image I've attached Channel 0 is connected the internal 1KHz 3.3v reference output, and channel 1 is floating. You can see that the noise as shown is ~0.1vp-p.

DS Labs Oscilloscope Noise.PNG
Screenshot showing oscilloscope noise
DS Labs Oscilloscope Noise.PNG (127.36 KiB) Viewed 1977 times


Regards,

Gavin
Avaron
 
Posts: 2
Joined: Thu Feb 12, 2015 12:49 pm

Hi Avaron,

Please try our new software - DSView:
http://www.dreamsourcelab.com/download.html

The noise should not be judged by the absolute value, It also depends on the vertical scale.

Thanks.
Andy
Site Admin
 
Posts: 149
Joined: Fri Jul 11, 2014 9:20 am

Hi,

I have seen similar noise levels using DSLogic 0.4.0 at around 100mV when using the ranges >= 500mV/div and around 3mV for the ranges below that.

I tried DSView 0.92 but in oscilloscope mode it locks up when I click on the start icon. This was on Windows 7 Ultimate sp1 (64bit), i7 2600k. Logic analyser internal test passes.

Thanks
Joe
Joe
 
Posts: 3
Joined: Sat May 02, 2015 7:21 am

Hi Joe,

Can you post the picture of the locks up?
By the way, the newest software version is v0.931 on windows. you can also have a try with this version.

Thanks.
Andy
Site Admin
 
Posts: 149
Joined: Fri Jul 11, 2014 9:20 am

I have the same issue with excessive oscilloscope noise. When I check 1kHz reference pin I see ~0.1V noise there. Here is the screenshot http://postimg.org/image/nzyvczk7j/full/

I built dsview from git HEAD, Linux Arch. Let me know if you need any information from me.
anatolik
 
Posts: 13
Joined: Wed May 20, 2015 4:02 am

Hi anatolik ,

As show on the picture you provided, the vertical resolution is 50mv/div
The noise level is about 0.2div, that means 10mv.
I guss you put the probe at 10:1 setting, but this rate should not be multiplied for noise calculation.
Andy
Site Admin
 
Posts: 149
Joined: Fri Jul 11, 2014 9:20 am

Hi,

I've tried having another go with the oscilloscope using the 0.9.4.1 software.

The result is the same, though I notice that changing the vertical scale no longer has any effect; the control appears to be broken atm.

I've attached a screenshot showing the current result. As it stands the oscilloscope is unusable.

Gavin
Attachments
Oscilloscope 0.9.4.1.PNG
Oscilloscope 0.9.4.1.PNG (99.42 KiB) Viewed 1545 times
Avaron
 
Posts: 2
Joined: Thu Feb 12, 2015 12:49 pm

Avaron wrote:Hi,

I've tried having another go with the oscilloscope using the 0.9.4.1 software.

The result is the same, though I notice that changing the vertical scale no longer has any effect; the control appears to be broken atm.

I've attached a screenshot showing the current result. As it stands the oscilloscope is unusable.

Gavin


Following is the steps to change vertical scale:
1. mouser left click to active the vertical dial
2. stay the mouser coursor within the dial region
3. using mouser wheel to set the vertical scale
Andy
Site Admin
 
Posts: 149
Joined: Fri Jul 11, 2014 9:20 am

Now I also got my Oszilloscope and I have also extreme noise problems.
I tried everything I can suggest, but nothing caused a change. When this goes on I have to throw the Osci into trash, its impossible to get usefull information with this noise. I also tried it with the reference signal, but its the same.

Is there an solve for that? Or if not, is it possible to refund it?

I use Win 10 and the newest software.
Attachments
Messung_2.png
Messung_2.png (200.52 KiB) Viewed 1208 times
Messung_1.png
Messung_1.png (200.25 KiB) Viewed 1208 times
Tropaion
 
Posts: 3
Joined: Thu Jan 14, 2016 2:22 am

Following is the comparisons between DSCope and Tektronix TDS3032B with different frequency square signal, generated by Agilent 33250A.

100Hz Square Signal:
TDS3032B
IMG_0833.JPG
100Hz Square Signal - TDS3032B
IMG_0833.JPG (214.76 KiB) Viewed 1195 times

DSCope
100Hz.png
100Hz Square Signal - DSCope
100Hz.png (116.22 KiB) Viewed 1195 times


1KHz Square Signal:
TDS3032B
IMG_0834.JPG
1KHz Square Signal - TDS3032B
IMG_0834.JPG (211.78 KiB) Viewed 1195 times

DSCope
1KHz.png
1KHz Square Signal - DSCope
1KHz.png (110.57 KiB) Viewed 1195 times


100KHz Square Signal:
TDS3032B
IMG_0835.JPG
100KHz Square Signal - TDS3032B
IMG_0835.JPG (207.21 KiB) Viewed 1195 times

DSCope
100KHz.png
100KHz Square Signal - DSCope
100KHz.png (118.48 KiB) Viewed 1195 times


1MHz Square Signal:
TDS3032B
IMG_0836.JPG
1MHz Square Signal - TDS3032B
IMG_0836.JPG (207.22 KiB) Viewed 1195 times

DSCope
1MHz.png
1MHz Square Signal - DSCope
1MHz.png (118.38 KiB) Viewed 1195 times


10MHz Square Signal:
TDS3032B
IMG_0837.JPG
10MHz Square Signal - TDS3032B
IMG_0837.JPG (205.8 KiB) Viewed 1195 times

DSCope
10MHz.png
10MHz Square Signal - DSCope
10MHz.png (119.74 KiB) Viewed 1195 times


We don't think there are any problem with the noise level.
The thickness of signal is not only related to the original signal, but also related to the frequency.
For a lower frequency signal, each point of signal on screen is composed of more real sample points.
For example, the comparisons between 100Hz sine signal and 10MHz sine signal

TDS3032B
IMG_0840.JPG
100Hz sine signal - TDS3032B
IMG_0840.JPG (221.18 KiB) Viewed 1195 times

IMG_0841.JPG
10MHz sine signal - TDS3032B
IMG_0841.JPG (223.13 KiB) Viewed 1195 times


DSCope
100Hz_sine.png
100Hz sine signal - DSCope
100Hz_sine.png (143.37 KiB) Viewed 1195 times

10M_sine.png
10MHz sine signal - DSCope
10M_sine.png (129.4 KiB) Viewed 1195 times
Andy
Site Admin
 
Posts: 149
Joined: Fri Jul 11, 2014 9:20 am

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