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REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol

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marmad:

--- Quote from: Circlotron on May 19, 2014, 06:54:58 am ---It would mean something is way wrong. With a sinewave input maybe there is some phase shift in the external analog circuit, but inputting two square waves with known identical corresponding transitions every 4 cycles, only different in frequency, it is a very easy test to reproduce, and if an anomaly shows up, then yeah, theres problems alright.

--- End quote ---

There is no anomaly from the Rigol in the images he posted. It's triggering exactly where it's supposed to: on the zero-crossing rising edge of the External Trigger input (or CH2, when he made the image to demonstrate the previous one). Any phase shift is, obviously, external.

So I don't see your point: you want another test to show it operates correctly again?

marmad:
Here's a repeat of Teneyes' demo, except using EXT. Trig as the source to a PULSE trigger.

1MHz sine to CH1 , with the AWG Sync Out signal connected to the External Trigger.
The Trigger is set for a positive PULSEs > 490ns.
Image #2 shows the same triggering replicated with CH2:

Teneyes:

--- Quote from: Circlotron on May 19, 2014, 01:32:40 am ---Teneyes, can you show us the same test using square waves, say from a synchronous binary counter chip? If there is a difference there, that would be serious.

--- End quote ---
@Circlotron & Others
  In my last report of a External trigger I used a sine wave to show how the external trigger was independant of the CH1 & Ch2 inputs.
 Below I repeated the test with two square waves the are Phase Aligned.
Note: I am using a DG4000 with 2 outputs. (lock)
In the display #1 you can see the 4 Cycles on Ch1 locked to the 1 cycle on Ch2
and in the Zoom part you can see the trigger  on Ch 2 works very accurately.

I then disconnected the 250KHz signal off of Ch2 input and connected it to the External Trigger input And the display #2 show the result.
CH2  in disconnected but still on.
Note that there appears to be about a  9ns offset between the "EDGE" External Trigger point and the CH1 trace.
Can anyone else verify this.  Just use a "T" connector and feed a square wave signal to both CH1 & External Trigger. Set the trigger source to EXT.

Also there appears to be about a  13ns offset between the "Pulse" External Trigger point and the CH1 trace.


I would think this trigger to trace offset could be compensated in the Firmware to display the Traces correctly when on external triggering. Is this a Bug? Is it only on the DS2000?


Please note that the External trigger requires an input >280mV to trigger and Count.
so if you see the Counter not working then the trigger will be jittering at first then NOT triggering at lower input signal.
There is not spec in the manual to the External Trigger sensitivity

Orange:
Teneyes,

I can confirm the delay of 9nS, also I see jitter of 500nS if I trigger externally.

On old Tek scopes you sometimes had the possibility to view the external trigger signal. Not so with the Rigol DS2000 series....

 

Orange:

--- Quote from: Teneyes on May 20, 2014, 08:52:55 am ---
--- Quote from: Orange on May 20, 2014, 08:17:50 am ---also I see jitter of 500nS if I trigger externally.

--- End quote ---

I see jitter on a weak signal. < 280mVpp
What was the amplitude of the signal in your test?

--- End quote ---
I tested with Sin Wave 100mV RMS, and with Sq wave 1Vpp. I did not see any difference in the jitter.

BTW 500nS should be 500pS  :palm:

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