This is just a heads up for those shopping for a digital scope. Rigol just launched a new budget for channel scope. It's rated at 50Mhz, 1GSa/sec, etc. The big thing is like it's bigger brother the DS1074Z, it's fully hackable up to 100Mhz, 24MPts memory, advanced triggering, serial decoding, etc. Also, just like the rest of the line, it has digital phosphor technology. The biggest thing is its only $399. At this point it's by far the best deal in digital scopes. You get basically everything you might need in a budget scope, for a very low price. You can get it even cheaper with education discounts etc. at certain vendors.
Sent from my LGLS990 using Tapatalk
Sent from my LGLS990 using Tapatalk
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I guess a link to the item would help:
Rigol DS1054Z Digital Oscilloscopes - Bandwidth: 50 Mhz, Channels: 4, Sampling Rate: 1 GS/S | TEquipment.NET
Also, the 30,000 waveforms/sec is an old number. Rigol released an update which results in the scope getting closer to 55-60,000 waveforms/sec.
Rigol DS1054Z Digital Oscilloscopes - Bandwidth: 50 Mhz, Channels: 4, Sampling Rate: 1 GS/S | TEquipment.NET
Also, the 30,000 waveforms/sec is an old number. Rigol released an update which results in the scope getting closer to 55-60,000 waveforms/sec.
No matter how much they will overclock them, their screen font is not going to become any larger. 😀
For older boys like me that font size is important, they should look elsewhere.
i ordered mine two days ago because it's fully hackable: 100 MHz, doubled Memory, Serial Bus Decoder, Advanced Trigger (someone reported he got 130 Mhz)
Http://Www.Eevblog.Com/Forum/Testgear/New-rigol-ds1054z-oscilloscope/
i posted a link to a teardown video there
Http://Www.Eevblog.Com/Forum/Testgear/New-rigol-ds1054z-oscilloscope/
i posted a link to a teardown video there
crappy waveform
I got one today and it's awful. compared to a 40mhz analog scope this thing is a kids toy. I stored a 600hz sine waveform from a loftech TS1 audio generator (reasonably low distortion). The Rigol is not symmetrical and flattens off the peaks. The trace looks like an amplifier with high frequency oscillations. The real time waveform of the analog scope looks much better than the one I attached due to reflections from the screen.
This this an anomaly or typical of what you get for $350.
I got one today and it's awful. compared to a 40mhz analog scope this thing is a kids toy. I stored a 600hz sine waveform from a loftech TS1 audio generator (reasonably low distortion). The Rigol is not symmetrical and flattens off the peaks. The trace looks like an amplifier with high frequency oscillations. The real time waveform of the analog scope looks much better than the one I attached due to reflections from the screen.
This this an anomaly or typical of what you get for $350.
Attachments
Neither, the thicker trace is pretty much real deal. Quite simply, analog scopes actually hide a lot of the transient information from the end user.
To quote Tektronix:
This is why intensity gradients (aka Digital Phosphor) features are very useful, by adjusting the intensity gradient you can vary from seeing anything and everything or you can adjust it to only see the stuff you care about. With an analog scope, you can only see what the phosphors allow you to see. If there is a seldom occurring transient that causes issues and the phosphors can't show it, you won't see it; whereas on the digital scope you can.
Additionally, if you hacked this system to give it the 100MHz bandwidth, you will have higher noise inherent to the system. I forget the name for this kind of noise but basically the wider the higher the bandwidth the more noise is injected into the system. This is why many scopes have a bandwidth limit function.
THe Rigol DS1054Z has been very well vetted at this point by both the internet and real professionals. Any major flaws have been found and documented and its noise floor is considered respectable. Across the board it is not ground breaking in performance but it is a very solid performer and from a value perspective it beats the pants off of most scopes even now over three years later.
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My employer has both an oscilloscope and a spectrum analyzer by Rigol. (I don't recall the model numbers at the moment.) I must grudgingly concede that they are a very good value as such instruments go. The user interfaces take a little practice to get accustomed to. They may not have cutting-edge performance, but I don't have any cutting-edge measurement challenges to evaluate them with.
Dale
Dale
Respectfully, did anyone actually look at the waveforms I presented. Please look at the disymmetry of the peaks of the Rigol.
We addressed the thickness. As for the other part, I believe you mean asymmetry as in the thicker trace on bottom than top. You don't quite clarify if you meant that or something else you might have seen like asymmetry in shape (ie more square character) or asymmetry as in lack of resolution.
If you mean asymmetry as in the thicker trace on bottom than top, then in a way we addressed that.
Short Answer: The asymmetry that you see is related to the discussed noise interacting with the trigger.
Long Answer: Because your trigger is near the top half of the sine wave, it is exacerbating the noise on the bottom. Basically, because there is noise in the signal (which is really there, even though your analog scope doesn't show it) it causes a bit of noise in where it triggers, as the scope basically triggers on the signal plus the noise. Because the trigger is at the same place on the screen EVERY time, you will commonly see this artifact in noisy signals; where the noise converges down to a point at the trigger. Basically, the bottom looks thicker because it is farther away from the trigger. Try shifting your trigger around to see if it changes how the noise looks. Try shifting it the same spot but on the bottom half of the sine wave to see if the noise shifts to the top. If it does, there is your answer. If it doesn't, then the asymmetry is really there and not an artifact of the scope.
Lastly, I will say one more thing. Just because your source can output a clean pure sine wave doesn't mean the signal reaching the scope remains that pure. Imperfect connections, induced noise, etc. can all enter the line between your source and the scope. Your analog scope can/will hide a lot of this, which a digital will show.
If you mean asymmetry as in the thicker trace on bottom than top, then in a way we addressed that.
Short Answer: The asymmetry that you see is related to the discussed noise interacting with the trigger.
Long Answer: Because your trigger is near the top half of the sine wave, it is exacerbating the noise on the bottom. Basically, because there is noise in the signal (which is really there, even though your analog scope doesn't show it) it causes a bit of noise in where it triggers, as the scope basically triggers on the signal plus the noise. Because the trigger is at the same place on the screen EVERY time, you will commonly see this artifact in noisy signals; where the noise converges down to a point at the trigger. Basically, the bottom looks thicker because it is farther away from the trigger. Try shifting your trigger around to see if it changes how the noise looks. Try shifting it the same spot but on the bottom half of the sine wave to see if the noise shifts to the top. If it does, there is your answer. If it doesn't, then the asymmetry is really there and not an artifact of the scope.
Lastly, I will say one more thing. Just because your source can output a clean pure sine wave doesn't mean the signal reaching the scope remains that pure. Imperfect connections, induced noise, etc. can all enter the line between your source and the scope. Your analog scope can/will hide a lot of this, which a digital will show.
By asymmetry I guess he is referring to the fact that the top point of the wave does not seem to be midway between the two bottom points.
I don't see that at all, to my eye it looks pretty close to center. Unless you mean that the top of the peak is not at the center of the screen. Which in that case is because his trigger is below the top of the peak. Unless you shift the time delay, center of the display will always be trigger of course.
Anyways, to test your comment, I actually calculated it. I estimated the peaks pixel by pixel and then measured the number of pixels between them. I ended up with 204 pixels on the left and 202 on the right. Considering the inherent error in my guessing the exact true peak location that is essentially perfect.
Anyways, to test your comment, I actually calculated it. I estimated the peaks pixel by pixel and then measured the number of pixels between them. I ended up with 204 pixels on the left and 202 on the right. Considering the inherent error in my guessing the exact true peak location that is essentially perfect.
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Yes - sorry!
It is the waveform on the analog scope that is asymmetrical, likely because of the way it was photographed.
By the way, are you affiliated with Rigol or have any financial interest interest in their products?
It is the waveform on the analog scope that is asymmetrical, likely because of the way it was photographed.
By the way, are you affiliated with Rigol or have any financial interest interest in their products?
Ahh misunderstood you!
No affiliation or financial interest or ties whatsoever. I just enjoy working on circuits as a hobby and love learning about (and repairing) test equipment. As such, I learn a lot about various brands of test equipment and like helping others out and answering questions (guess it is the scientist is me). Heck, I wouldn't even qualify as a Rigol fanboy, as I don't own anything Rigol (the closest are some friends own some Rigol stuff). My oscilloscope at home is a Keysight, bench DMM is an HP, handheld is a Brymen, etc.
Display Resolution: 800 Horizontal×RGB×480 Vertical Pixel
480 vertical dots is MUCH less than a good CRT's "resolution". These are absolute screen locations, so all data has to be rounded-over to hit the nearest available screen-dot.
There is additional blurr/smudge in your image. One reason *may* be that a 1-dot line is "too thin" so they double-up. Another point is that if your repetitive waveform is not DEAD repetitive (such as an AGC sine oscillator's wobble) the round-up/down will be different each cycle.
Ah-hah! Vertical Resolution: Analog channel: 8 bit
8-bit is 256 discrete values. How they map this onto a 480 pixel display (looks like 400px inside the graticle) is a nice question. The factor is 1.5625, which is not a nice number. Even 1.5 would produce odd/even line jaggies.
8-bit audio tells you what the song is, and the notes and words, but garbles all fine detail. This 'scope does too.
I had a hand-scope with 128-point ADC but 64-dot display. All these artifacts were too big to ignore. I learned to know what "sine-like" looked like, which is all I asked of it. It does not replace a good CRT (even my 1938 DuMont).
480 vertical dots is MUCH less than a good CRT's "resolution". These are absolute screen locations, so all data has to be rounded-over to hit the nearest available screen-dot.
There is additional blurr/smudge in your image. One reason *may* be that a 1-dot line is "too thin" so they double-up. Another point is that if your repetitive waveform is not DEAD repetitive (such as an AGC sine oscillator's wobble) the round-up/down will be different each cycle.
Ah-hah! Vertical Resolution: Analog channel: 8 bit
8-bit is 256 discrete values. How they map this onto a 480 pixel display (looks like 400px inside the graticle) is a nice question. The factor is 1.5625, which is not a nice number. Even 1.5 would produce odd/even line jaggies.
8-bit audio tells you what the song is, and the notes and words, but garbles all fine detail. This 'scope does too.
I had a hand-scope with 128-point ADC but 64-dot display. All these artifacts were too big to ignore. I learned to know what "sine-like" looked like, which is all I asked of it. It does not replace a good CRT (even my 1938 DuMont).
1. I greatly appreciate all of the responses here, even if my wisdom may have been questioned.
2. I posted only on this site as I wanted engineering based responses from credible people. Mission accomplished.
3. The symmetry I referred to was intended to mean the apparent thickness of the waveform at the top peak versus the bottom peak.
4. Most importantly, is the scope showing what is really there or is it distorting the wave form?
5. In the end I can't stand to look at this waveform. Is there another scope I should look at? All I'm really concerned about is linear circuits and some light duty digital.
2. I posted only on this site as I wanted engineering based responses from credible people. Mission accomplished.
3. The symmetry I referred to was intended to mean the apparent thickness of the waveform at the top peak versus the bottom peak.
4. Most importantly, is the scope showing what is really there or is it distorting the wave form?
5. In the end I can't stand to look at this waveform. Is there another scope I should look at? All I'm really concerned about is linear circuits and some light duty digital.
Moving from an analogue scope to a digital takes adjustment. The 1054z is great value for money. I use it for audio development and test. Wouldn't go back.
As mentioned, the asymmetry is likely due to the trigger location "clarifying" out some of the noise near the trigger point. Moving your trigger point closer to the zero crossing should return the peak to symmetrical. If it does not, it is 100% real. There have been zero reports of these scopes causing asymmetry in waveforms. If the trace is too thick, you can modify the intensity gradient to hide the less common stuff. By setting the persistence time to minimum and reducing the intensity you should be able to find a combination that works better for you. Also, turning on the BW Filter should kill some of the noise as well.
I'm going to take my scope to work tomorrow and compare it with the same scope we in the R&D lab. I hope to post the findings.
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