Poll

Do you believe in the myth of noiser digital oscilloscopes after watching episod #610 and #601

yes
3 (9.4%)
no
19 (59.4%)
confused
10 (31.3%)

Total Members Voted: 32

Voting closed: June 03, 2014, 10:08:31 am

Author Topic: Do you believe in the myth of noiser digital oscilloscopes  (Read 4320 times)

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Offline electrolux

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Do you believe in the myth of noiser digital oscilloscopes after watching episode #610 and #601?
The funniest thing about this signature is that by the time you realize it doesn't say anything its too late to stop reading it.
 

Offline zapta

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #1 on: May 04, 2014, 07:21:52 pm »
Do you believe in the myth of noiser digital oscilloscopes after watching episode #610 and #601?


If you want an honest discussion rephrase the question in a less biased way.

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Offline c4757p

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #2 on: May 04, 2014, 07:55:40 pm »
-1, Flamebait
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Offline ConKbot

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #3 on: May 05, 2014, 04:34:19 pm »
Personally, I only use stripchart recorders.
 

Offline Excavatoree

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #4 on: May 05, 2014, 04:59:13 pm »
Personally, I only use stripchart recorders.

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"10-4 Transmitting EKG.  We are sending you a strip.  Vitals to follow."

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Offline bogdan2013

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #5 on: May 05, 2014, 05:03:01 pm »
In my opinion , digital oscilloscope is limited at ADC steps and at screen pixels , is not a fine image how is at Analog scopes . So , I think both oscilloscopes have same noise level ...
 

Offline OrangeJacketGuy

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #6 on: May 05, 2014, 05:11:45 pm »
I reviewed those videos again and they have a great deal to do with oscilloscope noise, but not much to do with nois as stated in the question, so I voted "confused".
I rarely run into the issue myself since I have not used mine to measure signals that are so low in voltage. :-BROKE
 

Offline Fsck

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #7 on: May 05, 2014, 05:15:26 pm »
-1, Flamebait
^.

without any justification in the OP, seems like a +1 thread.
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Offline blackice504

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #8 on: May 10, 2014, 12:30:26 pm »
I would be more interested in the LCD refresh rate on the Digital Scopes vs CRT "for the young people that stands for Child Reproductive Thinners" as those sexy green glows are close to instant.

Please note that the green colour on these old scopes are not radioactive and the side effects of your shadow been burnt into the wall is the only side effect of using them.... ****tiny print: you maybe partially sterile from multiple uses****  :-DD

but if you do not mind all that you will get a fast refresh rate and i would bet it would be still faster then modern 1ms LCD's.

Nothing beats my Philips PM3055 60Mhz....... :P

Maybe this is why i do not have kids hmmmmm.
 

Online David Hess

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #9 on: May 11, 2014, 06:31:33 pm »
I can sum up my confusion with a quote:

"Believe in the Bible?  Hell, I've seen one!"
 

Offline Dread

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #10 on: May 11, 2014, 09:05:17 pm »
Anyone who is confused display yourself :)

I hear what Dave is saying and I would expect that newer expensive digital scopes would be much better than older expensive (at the time) Analog scopes.  My first thought when I watched video 1 was why have the inputs not been terminated.  Ok Dave in video 2 states that he did terminate them and it made no difference.

My confusion is this.

If God made me a perfect 10mhz signal Generator with probes and I feed a 100mv sine wave from it into both types of scope, the Analog one is going to show me a nice clean sine wave while the Digital one is going to show me a whole bunch of crap riding on the sine wave.   So where did this noise come from?

It's very logical to assume that Dave is right and I am not saying that he's not right but my own logic tells me something else is at play here.  I think that all those clock circuits in the fancy digital scopes bleed into the front end OR that the A/D converters are somehow creating the noise that does not exist or does not exist to the level we are seeing.

At the end of the day it's very confusing because I have this high end scope that no matter what I do shows several mv of signal and I don't think Dave has properly clarified where this noise is coming from other than to say "I am seeing something that is really there!"  There from where?

I would love to see this test redone with the scope in a shielded RF free cage and have the inputs terminated and see if the noise is still there.  If it is then it's got to be coming from the scope itself.  If it's not then my question is where exactly is it coming from in his original tests, the lights, other equipment, stray RF!   And all of this leaked in through terminated inputs?   Also if it is gone then it comes back to another issue, it's like having a 7 1/2 digit DMM and shorting out the leads and getting a 20mv reading.  If that the case every time I use the DMM I have to subtract 20mv from my readings.  With a Digital scope am I going to have to always ignore that noise?  If so what's the point unless you work in a shielded room and everything else in that room is perfectly emission clean.

BTW I am a Ham Operator and it's not uncommon in Ham Radio equipment world for a very expensive $10,000 radio to be inferior to a $2000 radio in the Receiver section.  Sometimes the need to design in as many bells and whistles also makes it difficult to make a Rx section that can match a much simpler straight forward design. 

BTW this is no critique of Dave, I loved those episodes, I am just not convinced because of the above reasons.
« Last Edit: May 11, 2014, 09:30:14 pm by Dread »
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Offline zapta

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Re: Do you believe in the myth of noiser digital oscilloscopes
« Reply #11 on: May 11, 2014, 09:16:00 pm »
I can sum up my confusion with a quote:

"Believe in the Bible?  Hell, I've seen one!"


That's a good one.

Never understood what 'believe in' means. I understand 'believe that' but what it's 'believe in'?

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