Q about DSO (Instek GDS-2102)

Hmm..... I can't tell you anything first-hand about the GDS scopes, but I do like my new Rigol DS-1102C.

US$1000 Download the manual and check it out. Their tech support quality (that I've seen with two things I contacted them about) was even better than the manual. Rigol makes scopes for Agilent. This line right here is the same as the Agilent 3000 series: The DS1000 series is the newer line with 1M buffer and thinner profile. Check out the math capabilities of the scopes.

Not affiliated yada yada, just happy so far. Full VGA would be nice though. ;-) Whatever you get, give a report. :-)

Hi Anthony:

I'm glad you are happy with your scope hopefully I will be so fortunate one day.

Thanks for your response. I sent another letter to GW Instek asking for an explanation, still no response. I just found the comparison table after I ordered the GDS-2101. I am hoping they respond before it arrives if the scope really does only have 100MSa/s real time per channel it's going right back without even opening the package. I'll fork out the extra $300.00 for the Tek which does have the 1GSa/s per channel.

These DSO manufacturers are getting ridiculous analog BW equivalent is IMHO when the sampling rate is at least ten times the fundamental signal. How some of these manufacturers are claiming these high equivalents Analog BW at these measly sampling rates is beyond me. Equivalent time sampling is another crock of shit you can use the cheapest A/D converters and then just have them refresh the screen at whatever rate you want and then say my scope has X equivalent Analog BW. And even at that the image your looking at still might not be a very accurate representation of the real signal, particularly if it is a non-repetitive waveform, are any intermittent transients, HF oscillations are present (the whole reason one uses a scope is to search for events like that).

I'm posting this to inform others verify that the advertised real time sampling rate is per channel if you don't get a timely response chances are it's not.

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though.

Other than ONE comparison chart, issued by a competitor, what evidence do you have that Instek's claimed 1Gs/s sample rate is incorrect? Their documentation, promotional materials and user's manual consistently state

1Gs/s maximum sample rate.

If I were selling a product and someone asked me a question I would respond.From my personal experience,the lack of a response is my evidence that the scope may be misrepresented.I have tried all possible avenues to receive an answer to what you would think would be a straight forwared simple question to the manufacturesrs. If the comparsion chart is incorrect Instek should demand they remove it and post a correction.

This is the question what is the real time sampling rate per channel of the scope, that should not be difficult to answer.Should require all of about 20 sec to fire off an email response.

And yes your right one would get the impression from all the promotional material out there that the scope does have 1Gs/s RT sample rate this was my assumption,and I hope I'm correct.At worst I would expect a 50/50 split per channel (500Msa/s).But 100MSa/s is useless.You could pick up a 15 yr old tek2230 with that rate for a couple hundred .

Oh ok then, I didn't realize you already ordered it.

I think you'll find that the sample rate will mostly be determined by the chosen horizontal sweep rate and sample buffer depth. At least mine seems to work that way. Maybe a firmware update will change this some day, but right now I can't really force the sample rate to some arbitrary value. The scope pretty much decides the sample rate it wants to use based upon the sweep rate. It will up the sample rate when I switch to the 1M sample buffer though. The higher the sample rate, the more sampling noise, so I tend to use the averaging feature for cleaner looking display.

I tend to agree with you on the bandwidth/sample-rate thing though. My scope will do up to 400MS/s yet is rated as a 100MHz scope. I think that is stretching things a bit, but I don't need 100MHz bandwidth anyway. If I did, I'd be looking for something claiming to be 400-500MHz. ;-) But doesn't that apply to traditional CROs as well?

The "equivalent" sample rate thingy is only applicable to repetitive signals, so for one-shot items the real sample rate is all that really matters there.

Maybe you should wait and see first. :-)

Well my question was answered,the scope has 500MSa/s per channel which is fine,and whatI intially assumed until I found that web site with the DSO comparision chart. The site still has the wrong information up though. I wonder why Instek doesnt make them take it down?