Do you believe in the myth of noiser  digital oscilloscopes - Page 1
Forum section: electronics / general

author: electrolux
author_rank: Regular Contributor
timestamp: May 04, 2014, 10:08:31 am
content: Do you believe in the myth of noiser digital oscilloscopes after watching episode #610 and #601?

author: zapta
author_rank: Super Contributor
timestamp: May 04, 2014, 07:21:52 pm
content: Quote from: electrolux on May 04, 2014, 10:08:31 amIf you want an honest discussion rephrase the question in a less biased way.Sent from my Nexus 5 using Tapatalk

author: c4757p
author_rank: Super Contributor
timestamp: May 04, 2014, 07:55:40 pm
content: -1, Flamebait

author: ConKbot
author_rank: Super Contributor
timestamp: May 05, 2014, 04:34:19 pm
content: Personally, I only use stripchart recorders.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: May 05, 2014, 04:59:13 pm
content: Quote from: ConKbot on May 05, 2014, 04:34:19 pm"Can you send me some EKG?""10-4 Transmitting EKG. We are sending you a strip. Vitals to follow."Obscure?

author: bogdan2013
author_rank: Regular Contributor
timestamp: May 05, 2014, 05:03:01 pm
content: 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 ...

author: OrangeJacketGuy
author_rank: Contributor
timestamp: May 05, 2014, 05:11:45 pm
content: 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.

author: Fsck
author_rank: Super Contributor
timestamp: May 05, 2014, 05:15:26 pm
content: Quote from: c4757p on May 04, 2014, 07:55:40 pm^.without any justification in the OP, seems like a +1 thread.

author: blackice504
author_rank: Contributor
timestamp: May 10, 2014, 12:30:26 pm
content: 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****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.......Maybe this is why i do not have kids hmmmmm.

author: David Hess
author_rank: Super Contributor
timestamp: May 11, 2014, 06:31:33 pm
content: I can sum up my confusion with a quote:"Believe in the Bible? Hell, I'veseenone!"

author: Dread
author_rank: Regular Contributor
timestamp: May 11, 2014, 09:05:17 pm
content: Quote from: electrolux on May 11, 2014, 01:15:01 pmI 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.

author: zapta
author_rank: Super Contributor
timestamp: May 11, 2014, 09:16:00 pm
content: Quote from: David Hess on May 11, 2014, 06:31:33 pmThat's a good one.Never understood what 'believe in' means. I understand 'believe that' but what it's 'believe in'?Sent from my Nexus 5 using Tapatalk