TDS-1002b Any good? Comments?

The 1000 mixed signal series is the newer series. The 5000 was their first offering. As mentioned in another post I have a Rigol 5102 in the lab, and whilst I haven't used it much, it is not a bad scope. It has some very nice features like digital filtering and masking, but you can't dump the screen to USB key, but I think you can on the newer 1000 series?

places:

No contest, the 1M sample memory (512K/channel) of the Rigol wins hands down. The lower 400MS/s sample rate is still high enough (just).

The Instek beats the Tek with it's 25K memory, but both get crapped on by the Rigol. You can do sooooo much more with that extra memory, you won't ever regret it.

Dave :)

Lemme see, a $3000 4 channel Tek compared with a $2000 2 channel Agilent (that's really a $1000 Rigol in disguise), yep completely "fair and balanced" on that count. ;-) I didn't notice Tek pointing out how the Agilent can do almost twice the number of automatic calculations. ;-)

Examining the disclaimers, I'm of the opinion that some of their "facts" may have been changed in later Agilent/Rigol firmware releases. Granted the Tek has its advantages too. For example the Tek has an on-screen clock. That's gotta help John keep his post-it photographs in order. (;-) Seriously, I'm sure the Tek is a fine scope, it's just too rich for my blood.

Ok, after I did some more looking I figured it out. I didn't figure they would double the size of the case on a later model.

It is my understanding that yes, you can dump to a memory stick plugged into the front. There is a port in the back for a printer as well. What scope do you primarily use?

places:

I kinda wish it had a higher sample rate, but most of what I do is so far removed from the upper bandwidth of the scope that I really don't think it should be an issue. Since I've never used a DSO before, I don't have much "feel" for all these numbers and their significance. I'm figuring it out though. :-) The comparisons on the TEK site are interesting and informative, even if they might be tilting things just a wee bit.

It might already be spent. ;-) Have you seen the Intronix LogicPort analyzer, it looks way cool with built in datastream decoding for SPI, I2C, serial ASCII and "more". 34 channels, should be more than enough for my needs.

The Rigol DS1102CD (note the 'D' on the end) has a 16 port logic analyzer. They want $500 for the option though. :-( The Intronix is less expensive and more functional (excepting that you could set up complex triggers with the analyzer built into the scope) Or do you think it would be wiser to go with the integrated analyzer.

There, I'm all set:

DMM: Extech MM-560 Oscilloscope: Rigol DS1102C Logic Analyzer: Intronix LogicPort

Now all I need is about $1600 to pay for it all. Paypal donations accepted ;-)

My primary scope is an Agilent MSO6032A (mixed signal 300MHz), with an older model Agilent 54621D mixed signal scope as the secondary. The Rigol brings up the rear as a cheapie throw around scope. Had a Tek

places:

Ideally you want the sample rate to be at least 10 times the bandwidth, so you can get some half-decent waveform resolution at the bandwidth limit. So for a 100MHz scope you want 1GS/s.

The GDS-800 series Goodwills are only 100MS/s for 100MHz bandwidth which is next to useless, you'd have to use interleaved (repetitive) sampling for anything over 20MHz or so.

The only other thing you need to know is that memory depth is just as important as sample rate! I do not know how I ever survived without a deep memory scope.

I'm pro-mixed signal scopes, they are just so versatile, and you don't need a PC to run it. But for home use a PC based logic analyser might be a good compromise, there are at least half a dozen good USB logic analysers on the market. Whichever one you get, make sure it has an external trigger input/output so you can connected it to the scope.

Does the wife know about this?

Dave :)

OMG, is that ever sweet! No wonder you don't mess with Rigol much.

Lost in transit...hmm...

places:

That sounds like a reasonable rule of thumb.

Sounds like you really go for the deep memory. I assume the scope captures even when it's not triggering so that you can go back and look at the events preceding the trigger. Is that right?

They have some new scopes that do 1GS/s that are replacing the 8xx scopes. Still _only_ 25K points though.

Yep, you like the big memory. ;-)

I can't find anything stating that the LogicPort has a trigger out. It samples real fast, so maybe they think you don't need a scope with it. It doesn't have a real deep buffer (2K x 34 pins), but should be fine for most things I can think of doing with it. I can't imagine needing 34 pins.

Shhh she doesn't do USENET. ;-)

places:

Correct. All DSO's will default to having the trigger point at half way in the buffer, so you get 50% pre-trigger info and 50% post-trigger info. But you can set it to 100% pre or post data, or anywhere in between.

You will too one day, trust me!

The 2K memory is pretty aweful these days, most USB analysers have a lot more - shop around. Deep memory is particually important for digital design.

Or know about that secret PayPal account huh? ;-)

Dave :)

I have a TDS 1012 and find it a little inconvenient not being able to scroll along (say) an ARINC429 32-bit comms transmission at a reasonable resolution on each bit.

I am curious about why the deep memory is so important to you. This comes up because I have only had a very small number of times where more than the 2k or so on the Tek would have made a difffernce. I do fpga design, general digital design, rf design, if design and low noise low frequency work. I cannot remember ever being unhappy that I did not have a meg of channel memory.

It's not just me, it's almost anyone who uses a DSO, hence the trend to larger memories in even the cheapest of DSO's.

I can't believe you have never needed more than 2K of memory in digital design, that is one area where a large memory is essential, but it you've never had it then you just won't know, you make do with what you've got.

With a scope with only 2K of memory you can only get say 10 cycles on screen and zoom in to see detail (200 points) in each cycle. With a large memory you can turn the timebase right down and capture 5000 cycles yet still zoom in with the same resolution on any cycle. So you can for instance see low frequency modulation on a signal, and then zoom in to see any high frequency glitches in any one of the thousands of cycles.

In digital design a large buffer lets you capture massive amounts of data and zoom in with full detail on say any byte in a 1000 character serial data stream.

For instance, last week I was debugging a GPS NMEA simulator design, and I had to capture several entire NMEA data strings (about 30 characters of RS232 data each) and be able to analyse each bit. Totally impossible with a scope with only 2KB of memory.

Another example from just today, I have been tracking down a digital bug in a third party product that only occurs once every few days or so at best. Data packets get sent once every ms, with a 2MHz data clock, and I want to be able to capture many of these packets, yet I also want to see fine detail in any one of those packets, and I only get ONE shot at it every couple of days. No problem on the large memory scope, simply set it to a slow timebase, it triggers capturing a large amount of packets and then I can spend hours post analysing every packet in detail.

Everyone in the company (and another company who shares our space) comes to borrow my scope all the time because the big memory is just so useful.

Once you have the capability you will never want to go back.

Dave :)

Not just anywhere inbetween, as delay allows you to trigger order of magnitudes before or after the displayed section.

Deep memory is so useful that after having it you curse any instrument you use that doesn't have it. The biggest day-to day advantage is you often don't need to be too careful in setting up a trigger - jsut grab a load of data and zoom in on the section of interest.

I use the 2K Teks but we have the 20 Meg Lecroy models at work at our EMI testing area, the Lecroy's are almost to the point where you don't need a trigger anymore, just press the single shot button and zoom in. Probably once or twice a year I really need the 20 Meg, mainly to capture independent glitches that occur over a long time period or capturing a serial bus data. Otherwise, I really don't need the Lecroy but they are a huge productivity improvement and a joy to use.

That's really nice. No more probe cables getting hot and letting of that plastics stench. AFAIR they are around $3k, sounds like a pretty good value.

I have nothing against digital scopes as long as their true sample rate is high enough. And as long as they don't spew EMI around, which many of them unfortunately do.

That's the first time I've ever heard Lecroy and "a joy to use" used in the same sentence! :->

Speaking of Lecroy DSOs, I can't believe what they go for on eBay, like this one for $1300, that is an insanely low price for a quad channel 500MHz, 2GS/s, 2Mpoint DSO.

Dave :)

magnitudes before or after the

Yes, very true. Although I don't think I've ever had to use this with a large memory scope, but common practice with the smaller memory ones.

Dave :)

really, well we all like them here, the tek's are being slowly replaced with lecroys, maybe we just have good lecroy salemen

DSO.http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&ih=013&sspagename=ST...

the older, heavy, probeless, mono "burned" screen, non usb (RS-232) scopes don't hold their value too long, regardless of raw performance, people like lightweight, color scopes with high modern connectivity

Yup! Many a thread has raged over the lack of "user friendliness" in the Lecroys. But like anything, you get used to them.

DSO.http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&ih=013&sspagename=ST...

Very true. But to get that raw performance in a new scope you have to spend at least 5 times that amount. So great value for those after the best performance-per-buck.

Dave :)

The sample rate is high though 500Msa/s, but I was most impressed by the protocol analysis/decoding. Oh well, I find that others can do the same thing.

The salesman from the other company just called and he doesn't have one in stock either. He does have the DS1101CD with the 16 channel logic analyzer.....hmm. That one captures at 200Msa/s with a 512K buffer, much much deeper, but it costs $500 more. Hopefully the PC software will be able to do protocol analysis/decoding. He's going to call me back with info on shipping and maybe even a discounted price.

I pretty much read the whole user manual. It certainly has features that I've wanted in the past. Just being able to see what happened before the trigger will be a boon. I doubt I really "need" this scope, but I sure do want it.

Of course not. You can just imagine how fast a bunch of engineers are filling it up for me. ;-)

As a general comment, I'm genuinely puzzled at the large number of people who need and seemingly make regular of, the pre trigger and pre storage facilities of digital scopes. Can't remember the last time I needed the facility. Am I missing out here, or doing something wrong, or thick or summat, or what?. john

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