Arbitrary Waveform Generator

[rkungl]

Hi, I'd like something mid to low range.

The waveform I'm going for is the following: a 2.5khz AC signal that is burst modulated at 50hz frequency with a 50% duty cycle.

Or just a best bang for the buck mid range function generator and I'll add circuitry to create my waveform.

I'd prefer the Arbitrary Waveform Generator approach because I need to evaluate many waveforms varying from 1-10Khz.

~Thanks

[rkungl]

can the DG1022 make that waveform very easily.  I found that unit for around $500 which is pretty much what I was looking to spend.

[Mechatrommer]

dds3x25 $100++. control is from PC or laptop.
the cheapest/MHz and lowest range i've seen. ymmv.

[Bored@Work]

can the DG1022 make that waveform very easily.  I found that unit for around $500 which is pretty much what I was looking to spend.

Problem with the DG1022 is the PC software. You don't want to type in up to 4000 values, each requiring 5 or maybe 10 key presses, for an arb waveform on the front panel. So the PC software is important. And in my experience it is absolute junk. Others claim it is wonderful. And service from Rigol is non-existent, especially if you buy from the grey market.

The also mentioned Hantke DDS 3x25 also comes with awful software, but there is some third-party PC software which is supposed to be good. And service from Hantek is non-existent.

By the way, your specification is incomplete. E.g. output amplitude is missing. The DDS 3x25 is a weakling when it comes to this. And most super-cheap generators, not the least DIY generators, have similar issues. The developers stopped after the digital part, and gave up when it came to a good analog output stage.

[ejeffrey]

Hi, I'd like something mid to low range.

The waveform I'm going for is the following: a 2.5khz AC signal that is burst modulated at 50hz frequency with a 50% duty cycle.

This waveform is easily constructed by the modulation features of many function generators.  Cheaper and analog generators will require a second source for the AM input, while many DDS generators will have the ability to generate the modulation waveform internally as well.  This does not require an arbitrary waveform generator, and in fact, you may run into issues with waveform length, especially with a cheap AWG.

[Jon Chandler]

dds3x25 $100++. control is from PC or laptop.
the cheapest/MHz and lowest range i've seen. ymmv.

Has anybody actually used one of these?  I have an application with modest requirements - generate a single sine tone at various levels at frequencies between 10 Hz - 10 kHz with the amplitude adjustable from perhaps 100 mV - a couple volts.  The biggest difficulty is that I need to be able to control this from a VB.net program.  I'd like to pass a parameter of frequency and amplitude, and step through a prescribed range.

A sound-card-based solution would work for me, but I haven't found any that can be controlled from another program.  I may break down and use "Direct Sound" to control a sound card from within my program but I haven't figured out how to do that yet.

Thanks,

Jon

[alm]

Jon: did you miss this thread?

[Jon Chandler]

Jon: did you miss this thread?

I did indeed.  My need just came up recently.  Looks like I have some reading to do!

Thanks

[rkungl]

Thanks everyone for you input.  I didn't specify the output voltage because I will have to amplify this signal anyway up to approx 150 Volts max (I doubt there are any units within my price range that can accomplish anything near that).  I would like an AWG because I will need to tweak the waveform.  If the software of the DG1022 is really that bad and the (4000 points) are limiting is there another alternative AWG that you recommend?

Also can someone point me to great bang for the buck function generator that could handle the waveform previously mentioned?

[rkungl]

it seems the dds3x25 suffers from jitter does the dg1022 suffer from jitter in the same way or is the signal much cleaner?

Does the dds3x25 suffer from jitter/other issues at 1-100khz speeds?

[rkungl]

Might go with a used 33120a @ approx $700.  Seems like a much better unit but I am still in the 'researching' phase.  Anyone have any positive/negative experiences with that unit?

[Nermash]

I don't have any experience with that model, but you can't go much wrong with Agilent:)

[ejeffrey]

I have used several of that model, most of them old enough to have HP printed on the case   They are an excellent general purpose function generator.  I can't speak to the AWG functionality, as I have never used it on any function generator (I have always used low speed DAQ cards or high speed digital pattern generators for arbitrary waveforms).  However, it will make the waveform you describe using its standard modulation features, and also has AWG if you need it.

[saturation]

mechatommer's software has solved the jitter problem, but at the frequency rises there is a fixed rising phase shift between Vout and the sync port.

The bigger issue was raised by marmad, the number of data points use to generate the waveform, I think its 1k.  That would increase the distortion as the frequency used rises; if you read arb specs many models have their cost rise proportionate to the length of the word used to generate the waveform.  So a lot depends on the fidelity of the output you need. 


Rigol has just released a new model line of arb generators too, FWIW that shows the differences.

http://www.rigol.com/prodserv/DG5000/property/

it seems the dds3x25 suffers from jitter does the dg1022 suffer from jitter in the same way or is the signal much cleaner?

Does the dds3x25 suffer from jitter/other issues at 1-100khz speeds?

[Mechatrommer]

since it is raised...

but at the frequency rises there is a fixed rising phase shift between Vout and the sync port.

what do you mean? doesnt that goltek's phase profile correct the phase shift? (or at least make it minimal? if not accurate). or are you talking about the noise affecting the synch from signal out?

The bigger issue was raised by marmad, the number of data points use to generate the waveform, I think its 1k.  That would increase the distortion as the frequency used rises

goltek provides way of using all the 4Kpts. but since the max sampling is 200MS/s, we only can go up to 48KHz, or 96KHz with 2Kpts and so forth.

Rigol has just released a new model line of arb generators too, FWIW that shows the differences.
http://www.rigol.com/prodserv/DG5000/property/

DG5101... goltek's ancestor kidding.

[saturation]

It has to be, you made the Hantek sing while I got it to grunt  .  Alas, I've been using the software you wrote before goltek, so I didn't realize it was a troglodyte compared to the improvements in goltek.  Will run it and see.  Mea culpa!  Sounds like you've fixed more issues and I'm out of date.

since it is raised...

but at the frequency rises there is a fixed rising phase shift between Vout and the sync port.

what do you mean? doesnt that goltek's phase profile correct the phase shift? (or at least make it minimal? if not accurate).

DG5101... goltek's ancestor kidding.
[/quote]

[Mechatrommer]

Alas, I've been using the software you wrote before goltek, so I didn't realize it was a troglodyte compared to the improvements in goltek.  Will run it and see.  Mea culpa!  Sounds like you've fixed more issues and I'm out of date.

hantek controller is a test program. goltek is the real program i developed for the device for my usage. basically they are like earth and heaven.
ps: is troglodyte a species of dinasour?

[ElektroQuark]

Troglodyte were our ancestors, they didn't know about AWGs