Tek AWG2041 how to generate short waveforms?

[AlexI]

Hi all - I recently got a Tektronix AWG2041 arbitrary waveform generator, it's the first AWG I've ever used.  Everything works pretty good, I figured out how to edit the waveforms using the on-board editor, and mostly how to program it using GPIB.

Only trouble is, it refuses to use any waveform shorter than 1024 points!  I can't find any mention of this in the manual either.  The manual does say the waveforms have to be a length which is a multiple of 32, and of course this supports really, really long waveforms (tested with 2M points), but short waveforms are a no-go.

I need to generate a signal that has 500 points and repeats a few hundred times.  That doesn't seem possible, unless I'm missing something. 

Is there some way in the AWG200 series to make it use just a portion of a longer waveform, so that it outputs less than 1024 points? 

Is there some way to make it output a repeated signal where the length of the repeat is not a multiple of 32? 

I'm pretty bummed out because the output waveforms don't seem all that "arbitrary"... producing this exact signal was the only reason I got this piece of gear.  Is this a common kind of limitation for AWGs?  Do I need a different AWG?

P.S. One other thing I tried is to make a long waveform which contains multiple back to back copies of the 500 point signal I want.  I had to write some code to load this over GPIB.  This worked - kinda! - the transfer works and looks ok in the onboard editor but the actual output glitches when the waveform is longer than 25k points.

[joeqsmith]

Hi all - I recently got a Tektronix AWG2041 arbitrary waveform generator, it's the first AWG I've ever used.  Everything works pretty good, I figured out how to edit the waveforms using the on-board editor, and mostly how to program it using GPIB.

Only trouble is, it refuses to use any waveform shorter than 1024 points!  I can't find any mention of this in the manual either.  The manual does say the waveforms have to be a length which is a multiple of 32, and of course this supports really, really long waveforms (tested with 2M points), but short waveforms are a no-go.

I need to generate a signal that has 500 points and repeats a few hundred times.  That doesn't seem possible, unless I'm missing something. 

Is there some way in the AWG200 series to make it use just a portion of a longer waveform, so that it outputs less than 1024 points? 

Is there some way to make it output a repeated signal where the length of the repeat is not a multiple of 32? 

I'm pretty bummed out because the output waveforms don't seem all that "arbitrary"... producing this exact signal was the only reason I got this piece of gear.  Is this a common kind of limitation for AWGs?  Do I need a different AWG?

P.S. One other thing I tried is to make a long waveform which contains multiple back to back copies of the 500 point signal I want.  I had to write some code to load this over GPIB.  This worked - kinda! - the transfer works and looks ok in the onboard editor but the actual output glitches when the waveform is longer than 25k points.

I have one and the sub 1K does not ring a bell.  Let me fire it up. 

[joeqsmith]

Ok, I checked the manual and then tried mine out.  Mine has code and format version 91.1 and firmware version 2.10.   I am able to go below 1024 with no problems. 
I normally use the sequencer so the minimum is 640 points.   I tried this out and indeed, below 640 I the ARB throws an error.   This limit may be found under the Memory Control.   According to the manual, even if you do not use the sequencer, you are still limited to the multiple of 32. 

[joeqsmith]

I am not sure what the problem would be at 25K.   I commonly will use well over this and don't have any problems with the output glitching.

[joeqsmith]

If I disable the hardware sequencer, I can go below the 640 limit at the manual suggests.  Setting for example 500 points the error message : 

Not multiple of 32 points. 12 added

  is displayed. 

Shown below with sequencer disabled and using 32 points. 

Normally if I need to synchronize an ARB with my hardware, I will provide a single clock and trigger.  I think with the 2040, you can drive it direct where the newer ones it gets a bit more difficult as I think they limit them to a 5GHz or something clock.   

[AlexI]

Joe - You're a lifesaver!  Thank you.  I figured it out from what you wrote... I just had to turn off the hardware sequencer.  Now it goes down to 32 (or 64, etc) no problem.

I can probably live with the 32 points limitation since this is a pretty sweet instrument.  I'll trigger it externally at the right time if I need a non-multiple of 32 repeat period.  Using an external clock is interesting, hadn't even thought about that... I'm not sure how to multiply the clock I do have (64MHz) to get something close to a GHz.

I'm writing GPIB code on Ubuntu, so I didn't know what the Tek windows software looks like, thanks for the screenshot it was interesting to see that.  If you or anyone else is interested in some example Ubuntu scripts I'd be happy to help.

[joeqsmith]

I agree, it's not a bad ARB for it's age. 

Just a couple of places I may have misled you.   I think on the 2040, the input sample clock is a 1:1.  So if you want to drive both the ARB and your target at 1KHz, I think you can just drive the ARB with the 1KHz.   Normally when I have done this, I setup a custom clock driver to get the ratios I need.   

I don't believe the 2040 will retrigger until after it has played back the waveform.  Just some details for you to dig into.  If you do use the trigger input to the ARB, you may find that synchronizing the trigger with a clock that is synchronized to your target may provide the least error.   As bad as the trigger is on the 2040, it seems the newer ones were worse. 

The software I show is something I threw together several years ago.  It needs a new look.  I actually have the software that Sony/Tektronix offered but have never played with it.  The software they supplied is named "WaveWriter" if you are interesting in looking into it. 

[TheNewLab]

OK, I have recently acquired a TEK AWG 2021. I was interested in it because of the 250MHz bandwidth generation..lo and behold, TE  really meant 250Ms/s.
top speed on all function generator features 2.5MHz
so how to get it faster??
after a lot of trial and error, I found an old floppy disk. formatted it, and began creating various wavefrom in the graphic mode

1. it defaults to 1000pt and 100MHz. I changed it to 64pts and 250MHz. (that is still only well do the math 250M/64...)
2. I then began entering one point high. (say1.5v) one point low(say.02v). I kept doing this until about 30 to 33pts. I stop there because for some reason it I continue doing the high low thing, the waveform stops displaying correctly and when I ran it, it was not a steady sine-wave.
3. I save the file and label it.(how a have a 64pt file with half of the file 1pt high low, and the rest flat line)
4. I then copied the file, renamed it and loaded it into the editor. I copied the 1st 30-32pt waveform created and added it to the end by pasting. added maybe one more cycle..or 32 +32 =64.
5. So now I have a AWG file that is a straight 2pt per wave.)
I then ran it and and varied the frequency through the clock speed
6. only the max was 125MHz. so how 250MHz??
7. I loaded the same file into both channels, offset the phase 180º and connected the two channels into one output -input to a single channel.

result is a decent sine-wave at 250MHz...I still have to work out the correct termination though...I think I am supposed to use a pass through terminator..only I don't have one..

I just needed a basic fast sine wave, however, right now I feel the 2.5MHz limit on the standard function generator signals is mostly useless..and I am not too excited about creating a whole collection of basic waveforms with the AWG, just to support the function generator needs.
It also runs so hot in my tiny lab....Only $250 vs. over $1,000 for a Rigol or Siglent or giddy forbid a solid mainstream $$ brand..

I hope this helps for those that were struggling to get over 63MHz sine-wave output from one of these.

[joeqsmith]

Manual on the 2021 is pretty clear.  Not sure why you would buy and arb based on what you were after. 

Sine Wave Characteristics   F.G mode, 100 kHz to 2.5 MHz, No Offset

[TheNewLab]

I was an oaf. saw a video on a Rigol or similar 160MHz Signal Generator. Wanted a signal fast enough to check a 200MHz scope. Saw the prices for the newer models, then saw used TEK that advertised as 250MHz, checked TEK website and manual said 250MHz...bought one...
Then I learned about Signal Generators and AWGs.

I am a hobbyist. I am way ahead of myself..having fun all the way...
The sine wave was just to check max wavefrom frequency the scope can capture reasonably. now I get to learn how to create various AWG models for uses I have yet to know of

[coppercone2]

Do you guys know where I can find a schematic of the CRT driver/power supply of that thing with the capacitor values? (not the main PSU)

I desoldered some bad caps in mine but I have no idea what I am supposed to put back, the project got interrupted. They all have the same one.

[PepaZdepa]

Do you mean this  ?

[coppercone2]

yes that.

I would personally recommend you replace all those caps. All of mine were leaky. I can't read the values that good from your picture though.

Symptom of leaky caps = screen fucking off every once in a while, getting dim, etc. Mine also smelled like cat piss.

I will tell you which values I need if you want to help me. Unfortunatly my PCB is different.

Maybe the values are the same. I need C302, C217 and C319. They are all near the fly-back transformer. I think it cooked them.

If you watch Mr.Carlsons l;ab though, he takes apart similar equipment (but I think it was a scope with the same PSU), and all the caps are bad in it too.

[PepaZdepa]

OK, my CRT module is Toshiba D7MM-01
The caps are (from left to right):
C423 - 10uF/250V
C416 - 100uF/50V
C415 - 470uF/16V
But I'm afraid, your module is completely different...

[kev009]

Ok, I checked the manual and then tried mine out.  Mine has code and format version 91.1 and firmware version 2.10.   I am able to go below 1024 with no problems. 
I normally use the sequencer so the minimum is 640 points.   I tried this out and indeed, below 640 I the ARB throws an error.   This limit may be found under the Memory Control.   According to the manual, even if you do not use the sequencer, you are still limited to the multiple of 32.

My AWG2041 is on FV 1.70.  Does anyone know how to update it, or dump the firmware in an existing machine?