Q about DSO (Instek GDS-2102)

H

Hammy

Guest
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.
 
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.
Click to expand...
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. :)
 
On Fri, 27 Apr 2007 21:05:58 -0500, "Anthony Fremont"
<spam-not@nowhere.com> 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. :)
Click to expand...
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.
 
"Hammy" <spamme@hotmail.com> wrote in message
news:mui6339i2h7un03gvabc48vfdlmnjfalg3@4ax.com...
On Fri, 27 Apr 2007 21:05:58 -0500, "Anthony Fremont"
spam-not@nowhere.com> 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 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.
Click to expand...
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.
 
On Sat, 28 Apr 2007 10:23:29 -0400, "BFoelsch"
<BFoelsch@comcast.ditch.this.net> wrote:

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.
Click to expand...
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 .
 
Hammy wrote:
On Fri, 27 Apr 2007 21:05:58 -0500, "Anthony Fremont"
spam-not@nowhere.com> 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
Click to expand...
Oh ok then, I didn't realize you already ordered 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).
Click to expand...

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.


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.
Click to expand...
Maybe you should wait and see first. :)
 
On Sat, 28 Apr 2007 11:56:44 -0500, "Anthony Fremont"
<spam-not@nowhere.com> wrote:

Hammy wrote:
On Fri, 27 Apr 2007 21:05:58 -0500, "Anthony Fremont"
spam-not@nowhere.com> wrote:



Maybe you should wait and see first. :)

Well my question was answered,the scope has 500MSa/s per channel
Click to expand...
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?
 
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