Rigol DG1022 vs. Agilent 33120A? - Page 1
Forum section: electronics / general

author: n3wbie
author_rank: Contributor
timestamp: May 27, 2012, 03:13:48 pm
content: I would like to purchase a decent frequency generator for hobby use and was leaning towards buying a used Agilent 33120A on ebay (they are going for about $500), until I saw that Rigol sells the DG1022 for $379. I've read mixed reviews about the Rigol, but the Agilent is known as a very reliable piece of equipment.So basically my question is this: would you recommend that I purchase the Rigol DG1022 new, or the Agilent 33120A used?Thanks for your advice

author: T4P
author_rank: Super Contributor
timestamp: May 27, 2012, 03:31:09 pm
content: Agilent. Small price premium, pity it's only a 10 megger arb gen but ah well.It's Agilent after all

author: Unknown
author_rank: Unknown
timestamp: May 27, 2012, 03:33:30 pm
content: Some notes when comparing the Agilent 33120A to the slightly older Rigol DG1012 a few years ago:In favor of the DG1012:USB and USB host100 MS/s instead of 40 MS/s14-bit instead of 12-bitSync out and ref out (similar to Agilent's option 1)Dual channelSine up to 20 MHz instead of 15 MHzTriangle up to 150 kHz instead of 100 kHzSymmetry adjustmentPulse feature (= square wave with different settings, no rise time adjustment)Against DG1012:Mediocre software: bad Intuilink clone, bad documentation, lacks features like equation editor, advanced pulse generation, does not work with all versions of the generator. Recommended way for generating complex signals appears to be to download Tektronix ArbExpress and import the signals from ArbExpress into the Rigol software.In favor of the HP/Agilent 33120A:More reliable brand, more likely to conform to specsGood software that's still being maintainedMuch better documentationFull programmer's manual with protocol documentationLower sine distortion? Better analog circuit?16 kpts instead of 4 kpts (at low sampling rates?)Square wave up to 15 MHz instead of 5 MHzFloating outputs instead of ??? (not documented by Rigol)Service manual with full schematics available, easier to maintain.In the end I chose the Agilent based on documentation (user, programmer, service) and software, since software is a fairly significant part of an arbitrary wave generator. You're not going to enter all those points via the front panel.

author: LaurenceW
author_rank: Frequent Contributor
timestamp: June 19, 2012, 09:41:28 pm
content: A lot depends on what you want to use your instrument for.I faced the same choice, but came down in the end on the side of the Rigol. it has a few quirks, but works well to spec. Certainly, on what I can reliably measure (frequency and amplitude) it is very easily within the published specs. Waveform rise times are (just) within the 20ns spec, too.One of those specs mentions that the ramp/triangle waveform only goes up to 150kHz (and indeed it does). This is pretty poor/slow, when compared to some other instruments. The Rigol is NOT the one to buy if you need faster ramps (though this may be an issue with the H/Agilent, too?)The DG1022 does feature TWO outputs, which happens to beveryuseful for my application; in fact it was probably the clincher. These outputs can be synchronised to one another, or phase-offset.One thing I wasn't expecting (and it's not documented either way), is that the output signal breaks up and suffers time/voltage glitches when you change (say) the frequency or amplitude of the output signal, even by small amounts. It's not like a smooth analogue volume or frequency control that you might experience on an older analogue frequency generator. Now, maybe I am being unfair on the Rigol, and that this is a trait of most budget priced digital instruments - I don't know. The glitch is only a fraction of a second, but the equipment to which your signal generator is attached might see this as a glitch pulse. It's not a problem if you are testing audio amps or suchlike.The Rigol's output ARE referenced to ground, by the way, and not floating. Not a big deal, as long as you are aware of it, and don't try and send the output to some other-than-ground referenced circuit.I do agree with other comments about the quality of the PC software. It's pretty-well useless (don't buy a Rigol for the PC software!)The DG1022 also features a frequency counter. It Kinda works, but does suffer a bit of jitter - even when measuring itself! There are limited triggering options. Using the frequency counter means giving up one of the two outputs. It is a bit of an afterthought and not what the machine is best at. It will not tempt me to give up my 25-year old HP Universal Counter! If you don't have a separate frequency counter, it will do a job.Another feature I would have liked (but not available on instruments at THIS price point) is a variable PWM (Pulse Width Modulated) output.Now, many of these criticisms are (probably) answered by the DG4062 design, but that's three times the price! So, to get back to the DG1022 price point - yes, I am happy with it. We should remind ourselves how lucky we are - five or certainly ten years ago, this functionality, particularly at these price points, was simply not viable.I've had a peak inside, and the construction is "Classic Rigol" - that is, good enough at this price point. No fan! it is silent. Nice form factor, but I wasn't too sure initially about the "Tonka Toy" style of corner bumpers. I'm over that, now, though. I'll do a tear-down video when I have the time.One last thing- a quick check on eBay suggests that second hand Agilent instruments are going at a hefty premium to new Rigols, so factor that in to your calculations, too!

author: antdes45
author_rank: Newbie
timestamp: October 25, 2012, 03:01:02 pm
content: From the tequipment.net website, the DG1022 is discontinued and we're left with the $499 DG1022A. Anywhere else it doesn't state it's discontinued, so it might be still possible to get it cheaper.Considering Rigol now apparently has a Windows 7 compatible software and there shouldn't be hardware revision problems with the 1022A, what would you choose between a DG1022A and the Aglient at both a 500 price point?Any infos on what the "Seamlessly interconnect with DS1000 series digital oscilloscope" feature is? I'm interested in a DS1052 scope to start with.

author: JuiceKing
author_rank: Regular Contributor
timestamp: October 25, 2012, 10:33:37 pm
content: The 33120A has <0.04% THD in the audio band, which is low for a function generator. The Rigol is <0.2%. I wasn't aware that the Rigol has a grounded output, but the 33120A is indeed floating. On the downside, the 33120A has a configurable output impedance of Hi-Z/50-ohm with no display annunciation, so you have to go deep into the menus to find out the setting, which is a nuisance. (It can be configured to survive power cycles, but still you forget how it was set from last time it was on. It's possible to recall a standard setup, which is what I do.) Duty cycle for the square wave is, I think, minimum 20%, so it's really limited as a pulse generator.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 25, 2012, 10:46:20 pm
content: QuoteYou connect the scope to the ARB's USB host port, and it can read captured scope waveform data and output it as arb waveforms

author: grenert
author_rank: Frequent Contributor
timestamp: October 25, 2012, 11:50:24 pm
content: Quote from: JuiceKing on October 25, 2012, 10:33:37 pmYes, I think that really shows the superior analog filtering in the Agilent, especially considering it has 2 fewer bits to work with. I notice there's no stair-stepping at lower frequencies. A moderately priced DDS from BK Precision that I used to have would show the amplitude steps at lower frequency, not sure if it had any filtering at all.

author: antdes45
author_rank: Newbie
timestamp: October 25, 2012, 11:56:01 pm
content: Thanks to all for the answers, sounds like the 33120A wins for THD. I'll have to get used to enduring it's menu system for the next few years in the school labs no matter how easy or hard it is to learn, so I guess it isn't that much of a problem. Floating outputs + separate square wave output sounds like a good thing to me, so I guess I'll watch eBay for a while to find a good deal.

author: piotr99
author_rank: Newbie
timestamp: April 01, 2018, 10:23:36 am
content: I know that the topic is very old, but Rigol has launched a new version of the generator - DG1022Z.I can buy a used 33120a (without 001 TCXO option) or DG1022Z in almost the same price.Rigol seems to be more functional (2 outputs, built-in 7-digit frequency meter) but Agility is much reliable brand.What do you think?