Digital Oscilloscope, buy advice needed
Ale
Posts: 2,363
Well,
After struggling to decide on the merits of several DSO, I decided to ask for a bit of advice.
My dilemma is that I'd like a good (for the price) DSO, in the range 1000 to 1600 Euro. I'd like:
- 4 channels (but 2 can do
- Deep memory (if this really makes a difference compared to 4, 5 or 6 kb of most of them, even the 2.5 k of Teks)
- High sampling rate (400 to 1 Gs/s per channel)
- Between 60 and 100 MHz
- new.
Uses: Digital and analog circuits, digital in the range of MHz, tens of MHz. Analog till 10 MHz or so. Microcontroller based things, with the Propeller and with AVRs and with eZ80.
The contenders are (sorted for price):
- LeCroy WaveJet 314 (3200 Euro, I have the money, but I can't justify it, but I'd really like it)
- Tek TDS2014 (1900 Euro, 4 CH, 2.5 k per channel, 1Gs/s, 100 MHz bw)
- Tek TDS2004 (1659 Euro, 4 CH, 2.5 k per channel, 1Gs/s, 60 MHz bw)
- Hameg HM-1008-2, (1570 Euro, 2 CH, 1M per CH, 500 Ms/s per CH, 100 MHz bw) (CRT, analog and digital)
- Rigol DS1062C (980 Euro, 2 CH, 512K per CH, 200 Ms/s per CH (or 100, I do not know)(ONLY 1 ADC !), 60 MHz bw)
- Rigol DS1162AC (960 Euro, 2 CH, 5K per CH, 1 GS/s per CH (ONLY 1 ADC !), 60 MHz bw)
My struggle is as follows, does it matter long memory dept ?, or with few kbytes is all the same. I have used analog Oscilloscopes in the past, and now I have a Tek 475, 100 MHz scope that is not mine.
Both Rigols exist in the 100 MHz range, but as I understand they only have one ADC, and samples are then interleaved, but it does not take many samples from one channel and then many of the other, just 1, does it matter ?
I'd really like the LeCroy, who not ?, It has everything I want but I do not think it will be an investment, more like spent money. I think the Hameg is a good choice.
Any help will be appreciated.
After struggling to decide on the merits of several DSO, I decided to ask for a bit of advice.
My dilemma is that I'd like a good (for the price) DSO, in the range 1000 to 1600 Euro. I'd like:
- 4 channels (but 2 can do
- Deep memory (if this really makes a difference compared to 4, 5 or 6 kb of most of them, even the 2.5 k of Teks)
- High sampling rate (400 to 1 Gs/s per channel)
- Between 60 and 100 MHz
- new.
Uses: Digital and analog circuits, digital in the range of MHz, tens of MHz. Analog till 10 MHz or so. Microcontroller based things, with the Propeller and with AVRs and with eZ80.
The contenders are (sorted for price):
- LeCroy WaveJet 314 (3200 Euro, I have the money, but I can't justify it, but I'd really like it)
- Tek TDS2014 (1900 Euro, 4 CH, 2.5 k per channel, 1Gs/s, 100 MHz bw)
- Tek TDS2004 (1659 Euro, 4 CH, 2.5 k per channel, 1Gs/s, 60 MHz bw)
- Hameg HM-1008-2, (1570 Euro, 2 CH, 1M per CH, 500 Ms/s per CH, 100 MHz bw) (CRT, analog and digital)
- Rigol DS1062C (980 Euro, 2 CH, 512K per CH, 200 Ms/s per CH (or 100, I do not know)(ONLY 1 ADC !), 60 MHz bw)
- Rigol DS1162AC (960 Euro, 2 CH, 5K per CH, 1 GS/s per CH (ONLY 1 ADC !), 60 MHz bw)
My struggle is as follows, does it matter long memory dept ?, or with few kbytes is all the same. I have used analog Oscilloscopes in the past, and now I have a Tek 475, 100 MHz scope that is not mine.
Both Rigols exist in the 100 MHz range, but as I understand they only have one ADC, and samples are then interleaved, but it does not take many samples from one channel and then many of the other, just 1, does it matter ?
I'd really like the LeCroy
, who not ?, It has everything I want but I do not think it will be an investment, more like spent money. I think the Hameg is a good choice.Any help will be appreciated.
Comments
One other spec to pay attention to is the available triggering modes. Base-level units will include level, rising-, and falling-edge triggering, with or without delay. Fancier models add things like pulse width, stateful logic (e.g. I2C start and stop), and video sync, to name just a few. Although you will use edge-triggering more than 90% of the time, the other modes really come in handy when you need them.
I've learned, mostly the hard way, not to scrimp when it comes to buying tools. A good oscilloscope will serve you well for many years. Get the very best one you can possibly afford. You won't be sorry. And if you can't afford new, buy a used or reconditioned unit. Ebay has tons of used test equipment.
-Phil
btw. I'd also like one of those or one of the Tek ones, or a LeCroy for that matter. For the time being, one of the cheaper ones will have to do
I recommend:
1. 100MHz or better, preferably 200 as a minimum.
2.·4 channels. I took this to work to use because I found I needed this feature for a couple of projects. This makes life soooo much easier.
3. A color LCD. I have run into situations where B&W traces produced confusion when the traces overlapped.
4. Lots of storage. We have a scope at work with 6k Points, and this proves very handy. 10k or better, for sure.
5. An ADC for each channel.·All of the above·is secondary to this factor, for me. I don't want to have to think how to compensate for interleaved or alternate samplings. Catch it all at the same time.
Have you checked out Instek yet? They have scopes with a decent feature set, for not much money. Also, do a search on all the forums here. Seems to me several posts discuss the pros and cons of different scopes, and the features one wants or needs.
Whatever you get, have fun with it!
kenjj
I would say that reliable and versatile triggering is one of the most important features in a 'scope. As are good controls. I like menus, but I also need knobs to twiddle for many of the basic parameters like gain and trigger point. Menus alone are just too slow. Bandwidth is important. In analog, it is little transients of a few nanoseconds you might want to see, or with the Propeller, a lot can happen with a 12.5 nanosecond clock. My fastest 'scope is 200mhz analog, and I often am left wondering about what I am missing that I am sure is there, somewhere.
The older discontinued models like the LT344 do turn up on ebay. Some are from dealers who ask top dollar and others from companies that are upgrading, and it certainly pays to look for the latter to get the best deal. And with assurances that it is working!
For portable use I have a rugged Tek model THS720, an old 100mhz 'scope with a slowwww micro inside for the control functions. (What they could do with a Propeller!) It has two channels and separate ADCs sample buffers but only 2500 points each channel. One really nice feature it has that you will hardly ever find in a bench 'scope is complete isolation between the channels, including its separate DMM channel. So it can make its measurements with less concern for common grounding or loops.
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Tracy Allen
www.emesystems.com
after much deliberation, I decided to go for the Rigol DS1042C (40 MHz bandwidth) Scope for a couple of reasons:
- Price.
- Deep memory.
- LCD instead of a CRT.
I decided that for the time being and the projects I'm working on now and the ones I have in the pipeline, this instrument *should* meet my needs.
What I found:
Well the scope works very well, deep memory vs normal memory (something like 2 or 4 k) helps a lot with high freq noise in low freq signals (easy to see in an analog).
Too many menus vs too few knobs: Well the menus are sort of fast to access, but they have sub-menus for common features, not so good idea. But the response is fast, does not waste loads of time drawing pretty boxes that do not bring detail nor functionality.
After some three or four days of use (and custom to an analog Tek), I can manage it very well.
The screen has nice horizontal viewing angles, vertical could be better but the contrast is high so even if the colorsa change a bit you do not get lost
Trigger: for slope, and slew rate works other modes not yet tested
Some people seem to bothered by the fan noise, but the lab I work at is even noisier (the ventilation), so it is ok.
I can post some shots of something if someone is interested and has some request.
btw: Of course I did not RFM
SOmething not mentioned in the manual are the sampling rates vs time and so on, don't ask me why, but here they are:
Normal memory: 50 points per division: i.e. 1 us/div means 50MS/s
Deep memory (512 k):
10 to 50 ns/div: 400MS/s (1CH) or 200 MS/s (2 CH)
100 ns/div to 200 ns/div 200MS/s
500 ns/div to 200 us/div 100 MS/s
500 us/div 50 MS/s
1 ms/div 20 MS/s
2 ms/div 10 MS/s
5 ms/div 5 MS/s
10 ms/div 2 MS/s
and so on, as you see it only pays at the high end
That is in Real Time, in equivalent things get a bit different at the high end.
Ale
Post Edited (Ale) : 5/14/2008 8:55:51 AM GMT
I've been considering the Rigol DS1102CD for a little while now.
But I've not heard much about the company.
Does anyone use Rigol equipment ? Is it "good" ? Does it hold up ?
Bean.
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Did you know that 111,111,111 multiplied by 111,111,111 equals 12345678987654321 ?
www.iElectronicDesigns.com
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From what I read in the German forums the logic analyzer in these equipments is rather poor. It contains 16 channels, samples at 200 MS/s at maximum, 512k samples (something good about it) but lacks features like protocol analysis, and trigger on a specified pattern (this last one needs confirmation).
I'd rather get a standalone LA, but well maybe the standard features are enough for you.
The screen is 320x234, so to see both analog channels and the logic ones... things get a bit crammed
The bandwidth for single shot on that model is 80 MHz, being 100 for repetitive trigger, in my opinion 200 MS/s for a 100 MHz scope... does not match very well. Maybe the 60 MHz is good compromise.
I went with the 40 MHz version more as a try than much else (besides its usefulness for my current projects). In the future if it does not perform, well I did not put all the cash in t.
From the company, I really do not know anything. I got 2 years (I hope) of warranty here and I am person who takes care of its machines so if it fails well it was not me.
Here there are a couple of resellers and from what I read, besides written above, people is satisfied for this price/features. Me included.
Sadly the next step in scopes is in the 5k range (for mixed signal) :-(, I hope they are reaaaly good when I buy one
Edit: I do not know if it has 1 or 2 ADCs !, think only 1 but I do not know how to test... well wth a signal that has 2 times the sampling freq and is sent to both channels... maybe something like that could be done
Post Edited (Ale) : 5/15/2008 4:14:46 PM GMT
I can't help you much. I can only say I've been looking at the same scope minus the LA. i.e. DS1102C
I have the same questions you have. Is it good, durable etc.
I already have a Intronix LogicPort LA, so I don't need the LA in the scope. Something I didn't think about when I was looking at LAs was the interpreters. They have made life so much easier for me. CAN, I2C, SPI and RS232 interpreters are now a requirement for me in a LA. Especially I2C, which I tend to use more. I only mention it because the price difference is about equal for more channels, faster speed, and CAN, I2C, SPI and RS232 Interpreters. May or may not fit your requirements. I admit, it would be nice to have all signals on one screen.
My scope search has come down to:
Rigol DS1102C
or
Link Instruments DSO-8502 (don't like the program but need FFT for radio work)
both companies, I don't know much about. Both are a grand which is my budget. I am finding very little info on the web.
Hope this helps and good luck on your search,
Chris
So the Rigol doesn't have interpreters ? I would have assumed it did...
If it doesn't, thank you for letting me know.
Bean.
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Did you know that 111,111,111 multiplied by 111,111,111 equals 12345678987654321 ?
www.iElectronicDesigns.com
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I read all the stuff I could find on the Rigol. I couldn't find anything. Just wanted to give you a heads up.
IF it does, cool. Go for it.
Maybe Ale can tell us if his new scope can do it.
Chris
oops, just saw he bought the 'C' version.
oops, just saw that you saw that I wrote that I bought the "C" version
What do you think of the Rigol scope ?
Good...Bad...Junk...Bargin... ???
Where did you buy it ?
Bean.
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Did you know that 111,111,111 multiplied by 111,111,111 equals 12345678987654321 ?
www.iElectronicDesigns.com
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I bought it from Conrad.de.