Author Topic: Rigol DG4xxx Signal Generator - Burst mode BUG  (Read 9270 times)

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Offline GonzoTheGreat

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Rigol DG4xxx Signal Generator - Burst mode BUG
« on: February 14, 2015, 02:02:43 AM »
I discovered two bugs in the burst mode of Rigol signal generators DG4062 and DG4102 and DG4162.

BUG #1:

Summary: When bursting 1-cycle square waveforms, the duty cycle of the output waveform suddenly changes from 0.01% to 99.99% between pulse widths 70µs and 200µs.

Steps to reproduce:
1) Set CH1 of your signal generator to the Square waveform (Period: 70µS, StartPhase: 0º, Duty Cycle: 50%)
2) Set the Burst mode of CH1 to (Type: N_Cycle, Cycles: 1, Burst Period: 1sec., StartPhase: 0º, Source: Internal, Delay: 0 ).

This will set your signal generator to output a 35µs positive pulse every 1 second (very low duty cycle).
(the pulse is 35µs wide because the duty cycle of the square wave was set to 50% and ½ of 70µs is 35µs)

Now, slowly increase the period from 70µs to 200µs using the Square waveform menu of CH1 (which I have highlighted above in green color) and observe on a scope how the polarity of that positive output pulse suddenly changes to a negative going pulse (the CH1 waveform inverts)  :o

Consequences:  If you had a PWM amplifier/load connected to the CH1 output of that generator, then it would blow up as the driving signal suddenly inverted its duty cycle.


BUG #2:  Several days later I have discovered another bug in the Burst mode.

Summary: When bursting 1-cycle square waveforms, the output signal suddenly disappears when the Burst mode Delay is rapidly decreased.

Steps to reproduce:
1) Set CH1 of your signal generator to the Square waveform (Period: 10mS, StartPhase: 0º, Duty Cycle: 50%)
2) Set the Burst mode of CH1 to (Type: N_Cycle, Cycles: 1, Burst Period: 100mS, StartPhase: 0º, Source: Internal, Delay: 89ms ).
3) Set CH2 of your signal generator to the same settings as CH1 was set above (it does not matter whether the output of CH2 is enabled).
4) Rapidly decrease the Burst mode Delay of CH1 from 89ms to 0ns (marked above in brown color) by using the numerical keypad + Enter and observe how the CH1 output pulses completely disappear for over 2 minutes.  Rapidly decreasing this Delay with the knob can have the same effect.
5) Watch how the CH1 output signal stays completely disabled, (even if the CH1 Burst Delay is increased to the previous value) until the CH1 output is cycled OFF and ON again, ...or the Burst mode is cycled OFF and ON again, ...or after ~138 seconds elapse.


Models affected (both bugs):
All DG4xxxx models running firmware up to v1.08 and v1.10.
I did not test these bugs on firmware v1.09 and above but other people did.

I would appreciate a confirmation of this bug from people running firmware 1.09 and above.
« Last Edit: February 21, 2015, 11:03:51 PM by GonzoTheGreat »
 

Offline OldNeurons

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #1 on: February 14, 2015, 04:03:41 AM »
I am on 00.01.09, and can not reproduce the bug you described.
 

Online PA0PBZ

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #2 on: February 14, 2015, 07:05:07 AM »
This bug was not tested on firmware v1.09 and above, because these firmwares "downgrade" the 200MHz model DG4202 to the 60MHz model DG4062.

Please note that if you change the model to DG4162 before upgrading you will be fine. So it's either a DG4202 with the bug or a DG4162 without it.
Keyboard error: Press F1 to continue.
 

Offline Teneyes

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #3 on: February 14, 2015, 06:18:52 PM »
I discovered a bug in the burst mode of Rigol signal generators DG4062 and DG4102 and DG4162.
Summary: When bursting 1-cycle square waveforms, the duty cycle of the output waveform suddenly changes from 0.01% to 99.99% between pulse widths 70us and 110us.
I can confirm this Bug on Software 1.08   Hard version 1.01  S/N <2000
Error occurs with any Number of Burst Cycles.
Error occurs with Burst period at least down to 400uS , could be lower.
Error occurs on Squarewave Period 73us or greater.

If on Square wave Frequency:
    No error Freq.  >=  13.87160718 KHz
     Error    Freq   <=  13.87160717 KHz
Any Ideas why the errors start at this boundary  :-//

Below I show No error then flip at 73uS Square wave period.

Could this be related to the Npulse Bug reported Here

Shoud I go to FW 1.09??


« Last Edit: February 14, 2015, 08:15:47 PM by Teneyes »
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Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #4 on: February 14, 2015, 08:27:42 PM »
If on Square wave Frequency:
    No error Freq.  >=  13.87160718 KHz
     Error    Freq   <=  13.87160717 KHz
Any Ideas why the errors start at this boundary  :-//
I don't know why the bug starts at this boundary but I know that it happens at different boundaries for different models.
For example in the DG4062 model, the error starts around the 100us boundary.
« Last Edit: February 14, 2015, 08:45:29 PM by GonzoTheGreat »
 

Offline OldNeurons

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #5 on: February 15, 2015, 12:41:54 AM »
After my first reply to 'GonzoTheGreat' yesterday, I upgraded my DG4062 to firmware version 00.01.10 (previously 00.01.09), and tried again to reproduce this bug.
In my case, this occurs exactly when I go from square wave period of 196.6080µs to 196.6081µs.
This doesn't occur when using pulse as source signal, but rising and falling time of pulse on the DG4062 are much longer than square.
 

Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #6 on: February 15, 2015, 01:17:57 AM »
I upgraded my DG4062 to firmware version 00.01.10 (previously 00.01.09), and tried again to reproduce this bug.
In my case, this occurs exactly when I go from square wave period of 196.6080µs to 196.6081µs.
I appreciate your vigilance despite the initial negative result. 
I have edited my initial description of the bug to cover that pulse width.
 

Offline OldNeurons

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #7 on: February 15, 2015, 01:59:55 AM »
@GonzoTheGreat

Could you try to setup phase in the burst mode to 359.999° and let me know your findings?
In my case, from 40ns to 200ms time period, no change in polarity.

For sure, there is a bug, but if this could help ...
 

Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #8 on: February 15, 2015, 02:21:46 AM »
Could you try to setup phase in the burst mode to 359.999° and let me know your findings?
Yes, it is a workaround.
Using the SYNC output on the front panel is a workaround, too - if you do not care about the lack of amplitude adjustment.
« Last Edit: February 15, 2015, 11:56:00 PM by GonzoTheGreat »
 

Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #9 on: February 18, 2015, 10:40:11 AM »
I have discovered a second bug in Burst mode and I have added it in this post.
« Last Edit: February 18, 2015, 10:50:53 AM by GonzoTheGreat »
 

Offline OldNeurons

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #10 on: February 18, 2015, 09:00:58 PM »
I have discovered a second bug in Burst mode and I have added it in this post.

I received an e-mail this morning, from Rigol U.S. telling me that a new firmware release for the DG4XXX series in coming soon ...
By the way, I tried to reproduce this 'second' bug on my DG4062, FW 00.01.10, and cannot get it.
May be it's there, but will occur at different conditions that yours.
 

Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #11 on: February 18, 2015, 11:14:30 PM »
By the way, I tried to reproduce this 'second' bug on my DG4062, FW 00.01.10, and cannot get it.
May be it's there, but will occur at different conditions that yours.
I've updated the steps needed to reproduce the Bug #2. Please try it again with the new values.
 

Offline OldNeurons

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #12 on: February 18, 2015, 11:43:44 PM »
By the way, I tried to reproduce this 'second' bug on my DG4062, FW 00.01.10, and cannot get it.
May be it's there, but will occur at different conditions that yours.
I've updated the steps needed to reproduce the Bug #2. Please try it again with the new values.

I tried again with your conditions and various other conditions for wave period, burst period and delay.
Can't reproduce the bug...
 

Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #13 on: February 18, 2015, 11:59:51 PM »
I tried again with your conditions and various other conditions for wave period, burst period and delay.
Can't reproduce the bug...
Maybe it was fixed in your firmware version.  Let's wait and see if the user Teneyes can reproduce it.
 

Offline OldNeurons

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #14 on: February 19, 2015, 03:12:44 AM »
I tried again with your conditions and various other conditions for wave period, burst period and delay.
Can't reproduce the bug...
Maybe it was fixed in your firmware version.  Let's wait and see if the user Teneyes can reproduce it.

Here is a copy of Rigol DG4xxxx firmware revision list (latest one).
I don't see for the latest version anything related to the bug you are facing.
 

Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #15 on: February 19, 2015, 11:32:29 AM »
I have amended the steps to replicate Bug #2 again here.  Please verify it.
 

Offline OldNeurons

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #16 on: February 20, 2015, 01:19:34 AM »
I have amended the steps to replicate Bug #2 again here.  Please verify it.

Bingo !!!
Same here with firmware 00.01.10.
I also discovered another bug in the AM, FM, ... mode. I will come back later with the description but I think that this one was not present before I updated the FW some days ago.

Do you intend to report that to Rigol?

Edit: Not sure if it's a bug, but feel it's annoying. Try this:

- Preset -> Factory defaults
- Output channel 1 ON. You should have at this stage a 1kHz, 5 Vpp signal on your scope.
- Press Mod (default values are AM modulation, 100Hz, Sine, 100% modulation.
- Change Shape to any other shape (Square, Triangle, etc ...). The signal goes OFF.
- Press Mod 2 times, or press Output twice to get the signal back with the new shape.

« Last Edit: February 20, 2015, 01:36:26 AM by OldNeurons »
 

Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #17 on: February 20, 2015, 04:45:56 AM »
Bingo !!!
Same here with firmware 00.01.10.
I applaud your patience.
Could you edit your older messages so new users skimming through this thread will immediately see that these bugs are replicateable ?

Do you intend to report that to Rigol?
No, I have difficulty communicating with them.

I also discovered another bug in the AM, FM, ... mode.

- Preset -> Factory defaults
- Output channel 1 ON. You should have at this stage a 1kHz, 5 Vpp signal on your scope.
- Press Mod (default values are AM modulation, 100Hz, Sine, 100% modulation.
- Change Shape to any other shape (Square, Triangle, etc ...). The signal goes OFF.
- Press Mod 2 times, or press Output twice to get the signal back with the new shape.
I'd say it's a bug, too.
My unit also behaves the same way as you described above.
 

Offline Teneyes

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #18 on: February 20, 2015, 11:58:02 AM »
I have amended the steps to replicate Bug #2 again here.  Please verify it.
Finally testing #2 bug
In order to better understand the Delay function in Burst Mode , I show below the Sync Out pulse on Ch. 2 of DSO
 Pix are:
    1. with 10ms Squarewave period and 100ms Burst Period
    2. with 10ms Sawtooth period and 100ms Burst Period 00 delay
    3. with 10ms Sawtooth period and 100ms Burst Period 20ms delay
    4. with 10ms Sawtooth period and 100ms Burst Period 50ms delay
    5. with 10ms Sawtooth period and 100ms Burst Period Maximum delay = 89.998ms

    6. with 10ms Squarewave period and 100ms Burst Period Maximum delay = 89.998ms,
        with Zoom to show 2ms reset time between bursts

    7. with 10ms Squarewave period and 100ms Burst Period 00 delay
         NO output on jump to 00 delay

Yes I can Confirmation the Bug #2 on FW 1.08
« Last Edit: February 21, 2015, 02:11:47 AM by Teneyes »
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Offline Teneyes

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #19 on: February 20, 2015, 12:04:31 PM »
Do you intend to report that to Rigol?
No, I have difficulty communicating with them.
I think it is not possible to get any response on a report of a bug in FW that is not the Latest version of released FW
« Last Edit: February 20, 2015, 01:01:51 PM by Teneyes »
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Offline Teneyes

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #20 on: February 20, 2015, 12:18:26 PM »
Same here with firmware 00.01.10.
I also discovered another bug in the AM, FM, ... mode.
Not sure if it's a bug, but feel it's annoying. Try this:
- Preset -> Factory defaults
- Output channel 1 ON. You should have at this stage a 1kHz, 5 Vpp signal on your scope.
- Press Mod (default values are AM modulation, 100Hz, Sine, 100% modulation.
- Change Shape to any other shape (Square, Triangle, etc ...). The signal goes OFF.
- Press Mod 2 times, or press Output twice to get the signal back with the new shape.
No confirmation for this Bug report on FW 1.08 , DG4202
« Last Edit: February 20, 2015, 12:21:28 PM by Teneyes »
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Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #21 on: February 20, 2015, 02:22:30 PM »
Finally testing #2 bug
In order to better understand the Delay function in Burst Mode , I show below the Sync Out pulse on Ch. 2 of DSO
Why is CH2 even monitored?
It does not matter if CH2 output is enabled - see pt.3 in the replication instructions ...it only matters if the CH2 Burst mode is enabled.
« Last Edit: February 20, 2015, 02:26:24 PM by GonzoTheGreat »
 

Offline Teneyes

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #22 on: February 20, 2015, 06:30:06 PM »
testing #2 bug
In order to better understand the Delay function in Burst Mode , I show below the Sync Out pulse on Ch. 2 of DSO
Why is CH2 even monitored?
It does not matter if CH2 output is enabled - see pt.3 in the replication instructions ...it only matters if the CH2 Burst mode is enabled.
In order to be describe the second (blue) trace in the Display
"I show below the DG4000 Chan.1 Sync Out pulse on Ch. 2 of DSO. in order to show the delay time from sync output until the single pulse is Generated"

Yes I missed the #3 point, thanks
Yes I can Confirm the #2 Bug in the display below I show the loss of output as I set the delay to 0
I will modify my  previous post

I also observed that the Output comes back On after about 140 Seconds without any intervention
See display 2.
But again this is with Old Firmware 1.08
« Last Edit: February 20, 2015, 06:34:59 PM by Teneyes »
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Offline GonzoTheGreat

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #23 on: February 20, 2015, 11:01:56 PM »
I also observed that the Output comes back On after about 140 Seconds without any intervention
See display 2.
But again this is with Old Firmware 1.08
Interesting, over 2 minutes....   :o
I have modified  the original description of the Bug #2 to reflect this.
I confirm this on my unit with firmware v1.08 but we still need to know if the output comes back after ~140sec with other firmware versions.
 

Offline OldNeurons

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Re: Rigol DG4xxx Signal Generator - Burst mode BUG
« Reply #24 on: February 21, 2015, 12:29:15 AM »
I also observed that the Output comes back On after about 140 Seconds without any intervention
See display 2.
But again this is with Old Firmware 1.08
Interesting, over 2 minutes....   :o
I have modified  the original description of the Bug #2 to reflect this.
I confirm this on my unit with firmware v1.08 but we still need to know if the output comes back after ~140sec with other firmware versions.

Confirmed with firmware version 00.01.10.
Output comes back after a bit less than138s.
 


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