Intensity grading comparison: Rigol's DS1104Z, DS2202, and Agilent DSOX3404 - Page 1
Forum section: electronics / testgear

author: rbola35618
author_rank: Frequent Contributor
timestamp: December 19, 2013, 04:15:29 pm
content: This is a quick comparison of the intensity grading of the Rigol's DS2202, DS1104Z and the Agilent DSOX3404 scope. The little DS1104Z packs very good intensity grading comparable to the much more expensive Agilent model.

author: echen1024
author_rank: Super Contributor
timestamp: December 19, 2013, 08:33:09 pm
content: Interesting. I own a DS1074Z myself (70MHz model, "upgraded" to Ds1104Z), and for the price, I must say that it is amazing. The intensity grading is very helpful.

author: eV1Te
author_rank: Regular Contributor
timestamp: December 19, 2013, 08:57:14 pm
content: Very nice video!Have a DS1000Z-S scope myself.

author: Fagear
author_rank: Regular Contributor
timestamp: December 19, 2013, 09:36:42 pm
content: While I was selecting between DS1074Z-S an DS2072A I noticed it as well. DS1xxxZ intensity grading feels better. More contrast, brighter traces.But I've selected DS2072A because of performance and features. And now I can tell exactly that "beam" brightness control doesn't do much at all. 0% or full 100% - little changes, some shades and nothing more. And very low contrast stays in place. Sometimes it can be increased by toggling "Anlialiasing" option in "Acquire" menu... but that's all.I don't care if my DS2072A has 256 steps of intensity. But if devices with 64 grades can do it better (even cheaper from the same manufacturer) - I don't want these 256 steps! Give me 64 steps but with good contrast!

author: van-c
author_rank: Regular Contributor
timestamp: December 20, 2013, 03:51:30 am
content: rbola,Just for grins I tried a test similar to your demo using video from a cheap board camera feeding my DS2072. Intensity grading appearance was virtually identical with your DS2202. I'm not yet running with the latest firmware update (v.2) but I'll be updating soon; maybe it will improve.

author: Mark_O
author_rank: Frequent Contributor
timestamp: December 29, 2013, 09:23:14 am
content: Quote from: rbola35618 on December 19, 2013, 04:15:29 pmVery interesting test. Thanks for doing it. I'd agree with your assessment.Now try it again, but with an HD video signal (720p or 1080i, your choice).

author: jadew
author_rank: Frequent Contributor
timestamp: December 30, 2013, 01:57:13 am
content: Hey, I'm a noob so I may be wrong, but I noticed that you're using 14Mpts memory depth on the DS2000 series and 7.5Mpts on the DS1000. That will make the update a lot slower, compared to the agilent one which has a lot less memory. This could also affect the contrast, since it might have more detail to display, which would make some areas brigther than the agilent one.Please let us know if you re-test with the same memory depth as the agilent and notice any difference in update speed / contrast.I'd like to get one of those 3 scopes as well, but I haven't made my mind yetThanks for the review.Edit: I also noticed that the sample rate is different.Edit 2: Sorry, I never looked into buying the agilent 3000 series, but the 2000 one.

author: Mark_O
author_rank: Frequent Contributor
timestamp: February 20, 2014, 01:40:00 pm
content: This topic just came up again in the I2C Bus Sniffing thrread, so I thought I'd respond to it here.Quote from: 3roomlab on February 19, 2014, 11:52:39 pmNo one here has ever made any comments to that effect. So it's doubtful.However, there's a couple things to keep in mind:a) the poster of the video, while he did a very good job demonstrating the differences overall (and this was a bit of an eye-opener to me as well), tended to concentrate on how the gradients looked at 50%. While he did temporarily crank all of them to 100% for a check, what he didn't do was back off on the DS2000, to aless than50% setting. If he had, the types of information in the signal he was looking for may have then been more visible. Or maybe not.Certainly the opposite was true... when he cranked the levels up to 100%, the visibility of the different regionsdecreased, in all cases. So 50% on the DS2000 may have simply been washing things out earlier then the other two. But unlike the others, the DS2000 didn't look as bad, as fast, because it had greater intensity bit-depth. The DSOX3000 definitely didn't look better than the DS2000, with both at 100%.b) he did mention the fact that the number of levels, which is dependent upon the intensity quantization level, varied between the 3 scopes. I'm not sure if he mentioned that both the DSOX3000 and the 1000Z had the same 64 levels, but he did say the DS2000 had 256. So two of them had 6-bit quantization, while the 3rd had 8-bits.Now anyone who has ever seen any substandard video displays is familiar with a defect called "posterization". The lack of bits in the quantization of the signal results in gradients that are stepped, and not smooth. In that context, being able to see the different levels is always a bad thing. However, when exploring analog signals in the intensity domain, it may actually yield superior results. At least in some cases. And his video demonstrated that pretty clearly. I.e., more isn't always better.Like him, I would pick the 1000Z over the DS2000, for examining baseband video signals. Unless, of course, backing off on the intensity from 50% improved the display on the DS2000. Unfortunately, he didn't go there in his video.

author: marmad
author_rank: Super Contributor
timestamp: February 20, 2014, 02:38:18 pm
content: Quote from: Dawgie on February 20, 2014, 02:28:08 pmCompared to what? To the Agilent 3000X? Well, I would hope it's update rate was faster - it costs 4-6x more than the Rigols.

author: Mark_O
author_rank: Frequent Contributor
timestamp: February 20, 2014, 05:33:48 pm
content: Quote from: marmad on February 20, 2014, 02:38:18 pmIt's not just the cost. There aretradeoffswith anything, and the special method (custom ASICs) that Agilent used to achieve those extreme refresh-rates meant that they're completely locked out from ever offering the very deep capture memories that the Rigols (even the inexpensive ones, like the 1000Z) offer. Rigols can do 24M or 56M sample depth, which is unavailable on DSOX3000's,at any price. I'm not making any value-judgement as to which is more important. Just stating that no solution is optimal in all respects.And if refresh rate is extremely important to you, you'll make sure that you've set the acquisition parameters to optimize it. Which the maker of the video did not, on the DS2000.And lastly (whew!), no mention was made of the fact that the DS2000 was providing more than 4 full scan-lines of video monitoring, due to it's 14-division wide display. The 1000Z was about 3.5, yet the expensive DSOX3000 from Agilent was less than 3 scan-lines! Perhaps that might count for something, for someone, some of the time.

author: NYG
author_rank: Contributor
timestamp: February 20, 2014, 06:06:21 pm
content: I made some samples from my DS2072A and posted them in the rigol bus sniffing thread. I'm by far from an expert so you can take this FWIW.I find that you have to drop the intensity below the 50% marker, even more if your looking down toward the scope. Viewing angle plays a role in the displayed image quality.The images are slightly darker here, again because I was looking from an angle above the scope and the display is a bit brighter from that angle.The last picture is with Anti-Aliasing on ( just tested it).I'm still new to the scope, so I may find other things that impact quality one way or another.There certainly are displays better than this one and the DS1000z may be one of them, but you can get a decent image on the DS2072A (at least from my eyes).

author: marmad
author_rank: Super Contributor
timestamp: February 20, 2014, 06:46:42 pm
content: Quote from: NYG on February 20, 2014, 06:06:21 pmI posted about this some months agohere; I tend to keep my DS2000 intensity level set to ~30%.It seems that the OP didn't really set the controls/memory depths of the various DSOs equivalently for the comparison video.

author: Mark_O
author_rank: Frequent Contributor
timestamp: February 21, 2014, 12:07:31 am
content: Quote from: NYG on February 20, 2014, 06:06:21 pmThanks for posting those, NYG. I suspected there might be gains to be had below 50% and you've confirmed it. Marmad's experience and comments back that up.Your first example looks best to me. I'd say it reveals evenmore detailsin the chroma-burst region than any of the video shots (including the Agilent). But those were from a vid-cam off-screen, while yours are snaps out of display mem. So they may have an unequal advantage due to that.Still, I'd think anyone would find it hard to fault them.

author: Mark_O
author_rank: Frequent Contributor
timestamp: February 21, 2014, 12:09:51 am
content: Quote from: marmad on February 20, 2014, 06:46:42 pmNo, he apparently felt that setting them all to 50% was "equal", without actually exploring the low ends at all.

author: marmad
author_rank: Super Contributor
timestamp: February 23, 2014, 01:58:17 am
content: Quote from: 3roomlab on February 23, 2014, 01:12:09 amAccording to published data, @ 5ms/div (which is the time base he's using in the video) the Agilent 3000X captures 18 wfrm/s. Since he's got the Rigol DS2000 set to a 14M memory depth, he's getting around 6 wfrm/s. OTOH, if he had set the Rigol to a 14k memory depth instead, he'd be getting around 14 wfrm/s.

author: rbola35618
author_rank: Frequent Contributor
timestamp: February 23, 2014, 03:28:35 am
content: Hi Guys,Sorry I couldn't do a more thorough comparison. Rigol sent me the two scope for a couple of days and ran out of time. What I want to see is that when I first evaluated the Rigol DS4000 series I noticed that the intensity grading was not as good as the Agilent DSOx3000 series. I also noticed that the brightness of the DS4000 and the DS2000 are much dimmer for my old eyes. I also noticed this on some of the videos that Dave posted where he uses the Rigol DS2000 scope. My first impression is that both are very similar and have the same characteristics. I do recall that I tried playing with the memory depth to see if it would increased the brightness of the screen and the intensity grading and failed to my satisfaction.The other thing that I did noticed on both the DS4000 and DS2000 is that the viewing angle are meant for the scope to be placed on the bench with the observer on top. When viewed from above, the brightness is acceptable (barely in my opinion). But when I placed the scope on the shelf and had a view right at eye level or slightly below, the screen seems to appear dim. So in my case, I prefer to have the scope on the shelve at eye level and therefore the Agilent seem to have a much greater viewing angle. The new DZ1000Z has a great viewing angle and to me seem to be much brighter than the DS4000 and the DS2000. Please keep in mind that the DS4000 that I evaluated had just barely released (early version) and may now have a better screen. Like I said in the video, what one sees may be subjective and what may not be acceptable to me might be OK for others. Maybe someone can do a retest of both scopes.Robert

author: Mark_O
author_rank: Frequent Contributor
timestamp: February 23, 2014, 05:13:55 pm
content: Quote from: 3roomlab on February 23, 2014, 01:12:09 amVery true. Except NYG's high-quality pictures are NOT photos. Nor did they come off the screen, as Robert's excellent video did. NYG's are digital snapshots, taken directly from display memory.I.e., what you see in those pictures is not necessarily what you'd see on the screen of the scope. (Which, if photographed, could look better or worse than perceived by the naked eye. Which is what we really care about.)

author: cyr
author_rank: Frequent Contributor
timestamp: February 23, 2014, 09:29:12 pm
content: I had a DS4xxx for a short while, and use an agilent DSOX 3xxx at work. I didn't compare them side by side like this, but I certainly agree that the rigol screen is generally a bit dim, the choice of base colors for the channels make them stand out less than the agilent and most noticeably the shading on the intensity grading is darker.