Re: Q about DSO (Instek GDS-2102)


"Hammy" <spamme@xxxxxxxxxxx> wrote in message
news:mui6339i2h7un03gvabc48vfdlmnjfalg3@xxxxxxxxxx
On Fri, 27 Apr 2007 21:05:58 -0500, "Anthony Fremont"
<spam-not@xxxxxxxxxxx> wrote:

Hammy wrote:
I am purchasing a DSO I found this Instek GDS-2102.

http://www.signaltestinc.com/ProductDetails.asp?ProductCode=GDS-2102

Which seems very comparable to TEKS TDS2012B (Only $300 cheaper).

What I find odd is that I also found this (DSO Comparison chart)

http://www.wittig-technologies.com/english/start_engl.htm

Which states that GDS-2102 which claims a 1 GS/s Real Time Sampling
Rate, has only a 100MSa/s per channel on a two channel scope this
equates to only 200MSa/s. How can they claim the 1 GS/s Real Time
Sampling Rate?

If someone could enlighten me I would appreciate it. I already tried
there techs as well as the manufacturers web site. Either no answer or
they couldn't explain it. Read the manual online still no explanation.

Hmm..... I can't tell you anything first-hand about the GDS scopes, but
I
do like my new Rigol DS-1102C.
http://www.rigolna.com/products_osc_DS1000.aspx
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:
http://www.rigolna.com/products_osc_DS5000.aspx
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 *** 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.

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.


.

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