Rigol DG4xxx Signal Generator - Burst mode BUG - Page 1
Forum section: electronics / testgear

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 13, 2015, 03:02:43 pm
content: 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)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)Rapidlydecrease 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 pulsescompletely disappearfor 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.

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 13, 2015, 05:03:41 pm
content: I am on 00.01.09, and can not reproduce the bug you described.

author: PA0PBZ
author_rank: Super Contributor
timestamp: February 13, 2015, 08:05:07 pm
content: Quote from: GonzoTheGreat on February 13, 2015, 03:02:43 pmPlease 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.

author: Teneyes
author_rank: Frequent Contributor
timestamp: February 14, 2015, 07:18:52 am
content: Quote from: GonzoTheGreat on February 13, 2015, 03:02:43 pmI can confirm this Bug on Software 1.08 Hard version 1.01 S/N <2000Error occurswith any Number of Burst Cycles.Error occurswith Burst period at least down to 400uS , could be lower.Error occurson Squarewave Period 73us or greater.If on Square wave Frequency:No error Freq. >= 13.87160718 KHzError Freq <= 13.87160717 KHzAny Ideas why the errors start at this boundaryBelow I show No error then flip at 73uS Square wave period.Could this be related to the Npulse Bug reportedHereShoud I go to FW 1.09??

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 14, 2015, 09:27:42 am
content: Quote from: Teneyes on February 14, 2015, 07:18:52 amI 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.

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 14, 2015, 01:41:54 pm
content: 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.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 14, 2015, 02:17:57 pm
content: Quote from: OldNeurons on February 14, 2015, 01:41:54 pmI appreciate your vigilance despite the initial negative result.I have edited my initial description of the bug to cover that pulse width.

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 14, 2015, 02:59:55 pm
content: @GonzoTheGreatCould 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 ...

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 14, 2015, 03:21:46 pm
content: Quote from: OldNeurons on February 14, 2015, 02:59:55 pmYes, 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.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 17, 2015, 11:40:11 pm
content: I have discovered asecond bugin Burst mode and I have added it inthis post.

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 18, 2015, 10:00:58 am
content: Quote from: GonzoTheGreat on February 17, 2015, 11:40:11 pmI 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.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 18, 2015, 12:14:30 pm
content: Quote from: OldNeurons on February 18, 2015, 10:00:58 amI've updated the steps needed to reproduce the Bug #2. Please try it again with the new values.

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 18, 2015, 12:43:44 pm
content: Quote from: GonzoTheGreat on February 18, 2015, 12:14:30 pmI tried again with your conditions and various other conditions for wave period, burst period and delay.Can't reproduce the bug...

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 18, 2015, 12:59:51 pm
content: Quote from: OldNeurons on February 18, 2015, 12:43:44 pmMaybe it was fixed in your firmware version. Let's wait and see if the user Teneyes can reproduce it.

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 18, 2015, 04:12:44 pm
content: Quote from: GonzoTheGreat on February 18, 2015, 12:59:51 pmHere 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.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 19, 2015, 12:32:29 am
content: I have amended the steps to replicate Bug #2 againhere. Please verify it.

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 19, 2015, 02:19:34 pm
content: Quote from: GonzoTheGreat on February 19, 2015, 12:32:29 amBingo !!!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.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 19, 2015, 05:45:56 pm
content: Quote from: OldNeurons on February 19, 2015, 02:19:34 pmI applaud your patience.Could you edit your older messages so new users skimming through this thread will immediately see that these bugs are replicateable ?Quote from: OldNeurons on February 19, 2015, 02:19:34 pmNo, I have difficulty communicating with them.Quote from: OldNeurons on February 19, 2015, 02:19:34 pmI'd say it's a bug, too.My unit also behaves the same way as you described above.

author: Teneyes
author_rank: Frequent Contributor
timestamp: February 20, 2015, 12:58:02 am
content: Quote from: GonzoTheGreat on February 19, 2015, 12:32:29 amFinally testing #2 bugIn order to better understand the Delay function in Burst Mode , I show below the Sync Out pulse on Ch. 2 of DSOPix are:1. with 10ms Squarewave period and 100ms Burst Period2. with 10ms Sawtooth period and 100ms Burst Period 00 delay3. with 10ms Sawtooth period and 100ms Burst Period 20ms delay4. with 10ms Sawtooth period and 100ms Burst Period 50ms delay5. with 10ms Sawtooth period and 100ms Burst Period Maximum delay = 89.998ms6. with 10ms Squarewave period and 100ms Burst Period Maximum delay = 89.998ms,with Zoom to show 2ms reset time between bursts7. with 10ms Squarewave period and 100ms Burst Period 00 delayNO output on jump to 00 delayYes I can Confirmation the Bug #2 on FW 1.08

author: Teneyes
author_rank: Frequent Contributor
timestamp: February 20, 2015, 01:04:31 am
content: Quote from: GonzoTheGreat on February 19, 2015, 05:45:56 pmI 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

author: Teneyes
author_rank: Frequent Contributor
timestamp: February 20, 2015, 01:18:26 am
content: Quote from: OldNeurons on February 19, 2015, 02:19:34 pmNo confirmation for this Bug report on FW 1.08 , DG4202

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 20, 2015, 03:22:30 am
content: Quote from: Teneyes on February 20, 2015, 12:58:02 amWhy is CH2 even monitored?It does not matter if CH2 output is enabled - see pt.3 in thereplication instructions...it only matters if the CH2 Burst mode is enabled.

author: Teneyes
author_rank: Frequent Contributor
timestamp: February 20, 2015, 07:30:06 am
content: Quote from: GonzoTheGreat on February 20, 2015, 03:22:30 amIn order to be describe the second (blue) trace in the Display"I show below the DG4000Chan.1 Sync Outpulse 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,thanksYesI can Confirmthe #2 Bug in the display below I show the loss of output as I set the delay to 0I will modify my previous postI also observed that the Output comes back On after about 140 Seconds without any interventionSee display 2.But again this is with Old Firmware 1.08

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 20, 2015, 12:01:56 pm
content: Quote from: Teneyes on February 20, 2015, 07:30:06 amInteresting, over 2 minutes....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.

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 20, 2015, 01:29:15 pm
content: Quote from: GonzoTheGreat on February 20, 2015, 12:01:56 pmConfirmed with firmware version 00.01.10.Output comes back after a bit less than138s.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 20, 2015, 02:17:55 pm
content: It would be good for Shahriar to show these bugs as a follow up on theDG4162 videothat he did a while ago. Maybe Rigol will take notice....Is anyone here in contact with him?

author: miguelvp
author_rank: Super Contributor
timestamp: February 21, 2015, 04:14:31 am
content: Quote from: GonzoTheGreat on February 20, 2015, 02:17:55 pmI believe member Hugoneus knows him wellhttps://www.eevblog.com/forum/profile/?u=8240

author: OldNeurons
author_rank: Regular Contributor
timestamp: February 21, 2015, 03:11:26 pm
content: Another bug.Setup:Rigol DG4062, firmware revision 00.01.10Metrix MTX3293 connected to DG4062 channel 1 output.All voltage measurements below are averaged values over 30s.Steps to reproduce:01- Let your DG4062 warm up for 30mn.02- Reset it to factory defaults. 'Preset' / O.K.03- Waveform / Arb / SelectWform / Builtin / Common / DC / Select / Arb04- Switch ON Output Channel 105- At this stage, you should read someting close to zero on your DMM (60µV in my case).06- Set 'Offset' value to 50mV. You should read something close to 50mV (50.033mV in my case).07- Switch Waveform type from 'Arb' to 'Sine'08- Switch Waveform type from 'Sine' to 'Arb'09- Voltage, in my case, jumps to 55.555mV (5.5mV increase).10- Set 'Offset' value to zero.11- Switch Waveform type from 'Arb' to 'Sine'12- Switch Waveform type from 'Sine' to 'Arb'13- Voltage, in my case, goes back to zero (60µV in my case).This "I don't know what" remains somewhere at 5.5mV for Offset values ranging from zero to 2.0000V.From 2.0001V to 10.0000V, this "I don't know what" jumps to 30mV.This jump corresponds to a relay status changing internally (you can here a click when going from 2.0000V to 2.0001V.I am curious to read your findings.Thanks for your feedback.

author: Teneyes
author_rank: Frequent Contributor
timestamp: February 21, 2015, 08:30:35 pm
content: Quote from: OldNeurons on February 21, 2015, 03:11:26 pmLet's Call this theArb-Sine-Arb BUGYes I can Confirm it, FW 1.08So Attached is Gif of these steps:1. Arb-> Sine -> Arb ,with Arb DC set =0.0mV. , frames 1-152. ArbDC =1.0mV. frame. 163 Arb -> Sine -> ArbBUT ArbDC comes back as 3.6mV.frames. 17-454. ArbDC = 0.0 mV .causes a Step of -1mV to 2.6mv Frame 375 Arb-> Sine -> Arb and offset back to 0 mv. frames 38- 62So it looks like the Sine Func corrupts the offset parameters for the Arb DC function.Was it because my sine wave function changes DC relays?

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 24, 2015, 07:09:31 pm
content: I confirm theArb-Sine-Arbbug with firmware v1.08

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: February 28, 2015, 01:43:10 am
content: I noticed a fourth bug!Namely, the SYNC output is not synchronized with the period of the waveform appearing on the OUT output generated with the "Harmonic" menu for certain 3rd order waveforms.By "not synchronized" I do not mean a constant phase difference. I mean a variable phase difference between the OUT and SYNCH outputs. The phase fluctuates wildly - maybe even 100ºNow, I am trying to figure out for what harmonic amplitudes this bug occurs...

author: Tom D
author_rank: Contributor
timestamp: February 28, 2015, 02:21:11 am
content: Quote from: GonzoTheGreat on February 28, 2015, 01:43:10 amMaybe the climate of Antarctica is wreaking havoc on your unit?Tom

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: March 02, 2015, 01:22:26 am
content: Quote from: Tom D on February 28, 2015, 02:21:11 amNo, I have a good bon fire going.Both of the bugs I have reported were replicated by others from warmer climates.I'd wager the 3rd one will be replicated, too, once I post detailed replication instructions.

author: Tom D
author_rank: Contributor
timestamp: March 02, 2015, 02:02:00 am
content: Thanks, Gonzo. I was looking at buying one of these, so I've been following this thread with interest. Nevertheless, I'm somewhat perturbed by your findings - I'm sorry to hear that you are having issues. I hope that this is only a firmware issue that will be resolved fairly quickly.Tom

author: Teneyes
author_rank: Frequent Contributor
timestamp: March 02, 2015, 12:38:27 pm
content: Quote from: Tom D on March 02, 2015, 02:02:00 amIt would be proper for Gonzo to modify the first post of this thread to indicate all bugs and in which Firmware revision the bugs exist and if the bug was corrected in later firmware .To be realistic, Rigol will evaluate a bug report and decide if it will be corrected.I have report bugs, and only after 18 months and,after the bug continued on to the next generation of devices andDave Joneshighlightingthe bug did Rigol correct it.These bugs on this thread are small, so just but be aware of them.

author: OldNeurons
author_rank: Regular Contributor
timestamp: March 02, 2015, 02:32:04 pm
content: QuoteI do not consider bug#1 as a minor one, but as amajorone.QuoteYes, good idea.Gonzo, do you intend to do so?QuoteSoftware is everywhere. In your car, your fridge, your oscilloscope ...Testing and debugging a new software is time consumming and costs money.Well, this is one of the reasons why some products are cheaper than other. They live factories before completion ... and final debugging is made by the end consumer.O.K., in our case, I have no problem to live for a certain period of time with a product which is only 95% finished.But, when end consumers take a part of their time to properly describe and report issues to the manufacturer, and when this go unanswered and without any corrective actions, then I start to have a problem, and this kind of situation will certainly affect my future equipments choices and recommendations ...I also found on my side another bug, not a serious one, but too much for me ... At the end, I will need a kind of 'Warning list' attached to this device.I'll come later with a description.

author: OldNeurons
author_rank: Regular Contributor
timestamp: March 02, 2015, 03:08:40 pm
content: So, here it is ...Description:Signal modulation stops when modulation shape is changed.Setup:Rigol DG4062, firmware revision 00.01.10Rigol DS2102A for signal monitoring.Steps to reproduce:01- Reset DG4062 to factory defaults. 'Preset' / O.K.02- Switch ON Output Channel 103- Press MOD. At this stage, you should observe a sine signal with 100% AM.04- Change SHAPE to SQUARE, TRIANGLE.. or whatever you want. At this stage the signal goes OFF.06- To restore the signal, there are 3 solutions. Press MOD 2 times, or press OUTPUT OFF and ON, or change the AM Depth to a new value.When AM Depth is different than 100% and SHAPE is changed, the signal freezes at low level of AM Depth value.If carrier signal is PULSE, instead of any other, then when changing SHAPE or DutyDev in the MOD menu, PWM will stop. Same medecine than above applies to recover...Still curious to get your feedback with same or different firmware version.Thanks.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: March 02, 2015, 06:08:57 pm
content: Quote from: OldNeurons on March 02, 2015, 02:32:04 pmI will do it.I think all bugs replicable on firmware v1.08 and v1.10, correct?I am a bit fuzzy about v1.09 though...Also, do you want me to add the Arb-Sine-Arb bug to the first post ?

author: OldNeurons
author_rank: Regular Contributor
timestamp: March 02, 2015, 06:46:32 pm
content: QuoteYes, sure, and also the last one "Signal modulation stops when modulation shape is changed."

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: March 03, 2015, 11:43:45 pm
content: Quote from: OldNeurons on March 02, 2015, 03:08:40 pmI was not able to reproduce any part of this bug on firmware v 1.08.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: March 03, 2015, 11:45:52 pm
content: Quote from: GonzoTheGreat on February 28, 2015, 01:43:10 amHere we go ...this behavior turns out to be a feature - not a bugBelow are the steps needed to replicate this behavior:1) Set the Rigol DG4xxx to factory defaults using the "Preset" button.2) Enable the Ch1 SYNC output on the front panel using the "Utility" button3) Enable Ch1 Output4) Set Ch1 to the Harmonic mode using the "Harmonic" button (Frequency: 100kHz, Amplitude: 5.0Vpp, Offset: 0.0VDC, Start Phase: 0.000º, Order: 2, Type: Even, SN: 2, Amplitude of the 2nd harmonic:3Vpp, Phase of the 2nd harmonic: 0.000º)5) Set your scope to display Ch1 output and SYNC1 output, while triggering on the SYNC1 output.6) Slowly increase the Amplitude of the 2nd harmonic (shown in green color in pt.4) to 6.0Vpp and observe the loss of synchronization on your scope.CONCLUSION: The period of the rectangular signal at the SYNCH1 output isnot related to the periodof the harmonic waveform on CH1 output, unless you set the CH1 "SyncMode" to "Carrier" using the "Utility" button.

author: Tom D
author_rank: Contributor
timestamp: March 05, 2015, 05:55:14 am
content: Thank you for the updates, Gonzo - your time and efforts are much appreciated.Tom

author: OldNeurons
author_rank: Regular Contributor
timestamp: March 23, 2015, 04:30:44 pm
content: I received an e-mail from Rigol U.S. one hour ago.A new firmware is available (00.01.11) and I am waiting for it ...It is supposed to be fully automated and should take a few minutes according the e-mail.I followed step by step the procedure and ... nothing yet after more than one hour now. I am not very surprised since previously, I had to ask Rigol US and Germany several times before I got something.If someone is more lucky than me, please let me know, and share ...Thanks !!!Edit : Link to the Rigol Web sitehttp://beyondmeasure.rigoltech.com/acton/form/1579/0012:d-0001/1/index.htm?id=0012