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.
@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