Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Notifications
Mark all as read
Q&A

Siglent1104 oscilloscope channels lagging

+5
−0

First I noticed that clock begins before chipselect gets pulled low on SPI. After eliminating potential sources I started to suspect the scope. I connected all 4 channels to function generator at different frequencies and observed 25ns gap between channel pairs. The probes were all the same 100Mhz stock probes that came with the scope set at x10, the 'deskew' was 0 on all channels. The 25ns was constant across different frequencies. On/off, auto calibration and factory reset did not fix the issue: Image alt text Image alt text

What could be the reason for this? Is this a bastard scope?

Why does this post require moderator attention?
You might want to add some details to your flag.
Why should this post be closed?

0 comment threads

3 answers

+6
−0

It was a firmware issue. SDS1xx4X-E Firmware Revision History And Update Instructions

The hardware delay between ADC acquisitions was not accounted for. I flashed the scope with new firmware and the delay is gone

Why does this post require moderator attention?
You might want to add some details to your flag.

0 comment threads

+3
−0

If all four channels are really connected to the same signal in the pictures you show, then there is indeed some skew between pairs of channels.

Try swapping probes to see if the lag goes with the probe or the channel.

Also try on the 1x setting. That should have less parasitic low pass filtering. Make sure the compensation of each probe is adjusted correctly. The compensation adjustment can have an effect on delay.

It looks like pairs of channels have the same lag. Is this the kind of scope that has plugin modules? If so, is the exact same model plugin installed for all channels?

Check the datasheet to see what the worst case skew can be when using the stock probes at 1x and 10x.

Why does this post require moderator attention?
You might want to add some details to your flag.

0 comment threads

+1
−0

Olin's response covered everything I would do in your situation as well. If the problem doesn't follow the probes and doesn't go away, I wonder if due to only two A to D inside the scope, this is the switching delay from primary to secondary channels?

Why does this post require moderator attention?
You might want to add some details to your flag.

0 comment threads

Sign up to answer this question »