Author Topic: Scope Purchase  (Read 1917 times)

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Online mtdoc

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Re: Scope Purchase
« Reply #50 on: January 12, 2018, 07:37:11 AM »
The issue is the amount of tiny video screen colored text required to operate a 1054z scope, not the font size on the controls which anyone familiar with a scope will not have to regularly read. Multiple menus and submenus and on screen data, decodes... oi vay! If you’re not over 50 you may not understand.

I sometimes had problems even on my Rigol 2072 which has a bigger screen than the 1054z.  On the other hand, i have no issues with my Tek 2467 which has a slightly smaller screen than the 2465b.

My R&S RB2004 is a joy with it’s large screen!

For a while DSOs routinely came with VGA outputs so an external monitor could be used.  This usually does not help with resolution but the size then becomes a matter of money and space.

Hopefully all DSOs will start to go the same route R&S did with the RB2000 scopes - a built in wifi accessible web browser display and interface.
 

Offline tautech

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Re: Scope Purchase
« Reply #51 on: January 12, 2018, 07:45:05 AM »
Hopefully all DSOs will start to go the same route R&S did with the RB2000 scopes - a built in wifi accessible web browser display and interface.
The new SDS1*04X-E has this too with either the LAN connection or the optional WiFi interface.

No more NIVISA or additional SW to remotely access or control a DSO.  :-+
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Online David Hess

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Re: Scope Purchase
« Reply #52 on: January 12, 2018, 10:53:22 AM »
For a while DSOs routinely came with VGA outputs so an external monitor could be used.  This usually does not help with resolution but the size then becomes a matter of money and space.

Hopefully all DSOs will start to go the same route R&S did with the RB2000 scopes - a built in wifi accessible web browser display and interface.

I would never by choice buy an oscilloscope or other test instrument which included built in Wifi.  I have no interest in wirelessly networked test instruments because of its security problems and because it becomes obsolete practically immediately.  If I want wireless networking, then I will use an access point through the wired network interface.

A direct monitor connection has the virtue of no practical latency unlike a network connection and Wifi just makes this even worse.  At this point, I have gotten used to browser applications having more latency then the serial terminal connected CP/M systems that I used in the past and they have only gotten worse as time goes by.
 

Offline Helix70

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Re: Scope Purchase
« Reply #53 on: January 12, 2018, 02:07:18 PM »
I think the bandwidth part of the hack is the least interesting or important part of the hack. I am rarely, if ever, finding myself needing it if I am being honest. I always laugh hearing about the hobbyists chasing high bandwidth, 10 bit adcs, and fft for use with their Arduino projects. You just don't need it. 4 channels on the other hand, advanced trigger options and serial decoding, all very relevant for the hobbyist.

No amount of finesse can make up for inadequate bandwidth but it is often possible to get by with fewer channels especially if you make use of the external trigger.

Instead of thinking in terms of bandwidth, think in terms of transition time.  25 MHz TTL is about 3.5 nanoseconds which is 100 MHz for an oscilloscope.  100 MHz FAST and AS TTL is almost 1 nanosecond which is 350 MHz.  Common low voltage CMOS logic is closer to the later than the former and no matter what the clock speed is, the fast edge is what matters and a 100 MHz oscilloscope can completely miss problems like double clocking even with the "slow" logic associated with an Arduino.

I do the same thing rstofer does.  I have a 100 MHz DSO for general purpose use and inexpensive used analog oscilloscopes for high bandwidth when needed for signal integrity analysis.

Never, in all of my years, has this been an issue for me, and I am a professional engineer. I have a 100Mhz scope at work (a fancy one admittedly), and it shows every digital signal I am likely to ever need just fine. Don't confuse the timebase with the sampling rate.

I am not saying some people don't need more than 100Mhz, that is stupid. What I am saying is hobbyists benefit the least from bandwidth increases in scopes, as they probably are not getting the appropriate probes to handle the rise times anyway. They also don't understand probe impedance, and ground lead length and all of a sudden, they are seeing stuff on the screen that just isn't real.

Keyword = hobbyist.
 

Online mtdoc

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Re: Scope Purchase
« Reply #54 on: January 12, 2018, 02:35:02 PM »
I would never by choice buy an oscilloscope or other test instrument which included built in Wifi.  I have no interest in wirelessly networked test instruments because of its security problems and because it becomes obsolete practically immediately.  If I want wireless networking, then I will use an access point through the wired network interface.

My RB2004 is only networked in the sense that it is connected to a single computer (or sometimes a tablet) and there is no internet connection to that router.  I have an old WiFi router dedicated to the purpose. It could just as easily be a wired connection- I just prefer no wires. Not sure why you would be concerned about security.. and what is going to become obsolete??

There really is no noticeable latency. See Mikes review video - he felt the same.
« Last Edit: January 12, 2018, 02:41:47 PM by mtdoc »
 

Online beanflying

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Re: Scope Purchase
« Reply #55 on: January 12, 2018, 02:58:36 PM »
I started with 20MHz scopes in secondary school, nicer HP stuff in Uni and brought my 20MHz usb Hantek Scope/Logic quite a few years ago thinking it would be all I would need. Jumping ahead a few years the bus decoding/MSO is becoming more important to me as a feature much more than a bandwidth increase being needed.

To get the fancier features I wanted I found myself pushed up to the 100MHz which then became a juggle between branded older s/hand (Agilent 54622D most likely) or looking at the usual list of Asian built modern ones. Sifting through the current frequently changing range is hard work and distilling actual features from bs and hype is also a battle. This seems like it will get harder as manufacturers compete to win a chunk of this lower end market.
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Online DDunfield

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Re: Scope Purchase
« Reply #56 on: January 12, 2018, 11:30:03 PM »
I think the bandwidth part of the hack is the least interesting or important part of the hack. I am rarely, if ever, finding myself needing it if I am being honest. I always laugh hearing about the hobbyists chasing high bandwidth, 10 bit adcs, and fft for use with their Arduino projects. You just don't need it. 4 channels on the other hand, advanced trigger options and serial decoding, all very relevant for the hobbyist.

No amount of finesse can make up for inadequate bandwidth but it is often possible to get by with fewer channels especially if you make use of the external trigger.

Instead of thinking in terms of bandwidth, think in terms of transition time.  25 MHz TTL is about 3.5 nanoseconds which is 100 MHz for an oscilloscope.  100 MHz FAST and AS TTL is almost 1 nanosecond which is 350 MHz.  Common low voltage CMOS logic is closer to the later than the former and no matter what the clock speed is, the fast edge is what matters and a 100 MHz oscilloscope can completely miss problems like double clocking even with the "slow" logic associated with an Arduino..

The point I was trying to make (and didn't actually state as such apparently) is that if you want the "best" scope (for YOU .. there is no best scope for everyone) you really need to figure out your requirements - I know this may not be easy for a hobbyist setting up a home lab, but you should be able to come up with a pretty good idea of the types of things you want to work on - from that determine your NEEDS and WANTS, do some research is pick the scope that best suits these parameters. If you just ask "what scope should I buy" in a forum like this, you will get information based on others peoples needs and biases.

It is easy to fall into the trap of "What if I need to see this someday" - one could argue that digital signals really want to be square waves, and in order to see every nuance of a square signal you really should get yourself an infinite bandwidth scope with infinite sample rate - then there would NEVER be an artifact that you would not be able to see, even as technology gets faster and faster.

Unfortunately such a scope is unobtanium and the ones that come closest to that goal are VERY far beyond the reach of most small companies and hobbyists and usually need some pretty serious budget approval even in a large company.

So clearly a compromise in in order.

Through the 70-90's myself and other colleagues worked on TTL systems not realizing the 10-20Mhz scopes we could afford were too slow to be useful. But we saw everything we needed to see and produced a boatload of reliable products.

Were these 100Mhz or even 25Mhz TTL? NOPE  ... and I'd bet most of the signals hobbyists are driving out of their arduinos aren't either. As noted in my first post, if you are working on high-speed modern designs then yeah - you need uber-fast tools. But such design work is beyond the scope of most home-labs so planning (and spending) for it may not make sense.

I'm not saying YOU don't need a 100Mhz (or faster scope). Only YOU can determine what you actually NEED/WANT, and therefore only YOU can determine what is the "best" scope for YOU.

But be aware of the compromises. In chasing the holy-grail of bandwidth (and diverting your purchase dollars that way), you may end up spending a large about of your time "getting by" without capabilities and features that would make your work easier on a day to day basis - but only YOU can choose the right compromise.

Btw: If you're patient (or lucky) you might be able to come pretty close to the best of both world without spending a lot - My TDS380 cost me $30 ... a client was e-cycling it because "it had a bad input", so I brought it home and took a look - someone had replaced one BNC connector with a non-Tek part that swapped ground and probe sense .. a replacement cost me $30 and now it works perfectly.
« Last Edit: January 12, 2018, 11:32:02 PM by DDunfield »
 

Online DDunfield

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Re: Scope Purchase
« Reply #57 on: January 12, 2018, 11:48:33 PM »
I would never by choice buy an oscilloscope or other test instrument which included built in Wifi.  I have no interest in wirelessly networked test instruments because of its security problems and because it becomes obsolete practically immediately.  If I want wireless networking, then I will use an access point through the wired network interface.

While I am of the same mindset, I do recall one wifi scope that looked interesting. I think it was Velleman who made it, and it had no on-device controls - you had to control it through a tablet or computer over WiFi and it had a built-in battery. In other words, in operation nothing touches the scope except the device under test.

It looked promising as a tool to use instead of "floating" a benchtop scope which is quite dangerous if you don't know what you are doing (actually it can be quite dangerous even if you do know what you are doing).

Unfortunately IIRC it was really low bandwidth, and the software was reported to be horrible and unsupported so I never did pick one up - but I did consider it.
 

Offline tautech

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Re: Scope Purchase
« Reply #58 on: January 13, 2018, 12:11:54 AM »
I would never by choice buy an oscilloscope or other test instrument which included built in Wifi.  I have no interest in wirelessly networked test instruments because of its security problems and because it becomes obsolete practically immediately.  If I want wireless networking, then I will use an access point through the wired network interface.

While I am of the same mindset, I do recall one wifi scope that looked interesting. I think it was Velleman who made it, and it had no on-device controls - you had to control it through a tablet or computer over WiFi and it had a built-in battery. In other words, in operation nothing touches the scope except the device under test.

It looked promising as a tool to use instead of "floating" a benchtop scope which is quite dangerous if you don't know what you are doing (actually it can be quite dangerous even if you do know what you are doing).
This is a common albeit risky procedure and even with floating a 'remote control' scope, you're still limited to just use of one channel if other channels don't share the same reference point.
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Offline nealfox

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Re: Scope Purchase
« Reply #59 on: January 13, 2018, 11:58:08 PM »
I wish to thank everyone who took the time to respond to my query.  It has been very helpful.  I did consider both the Analog Discovery and the MICSIG but prefer a traditional scope.
I’m going to order the Rigol DS1054Z from TEquipment.NET.  It is on sale for $349 which includes free software bundle.
 
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Offline Old Printer

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Re: Scope Purchase
« Reply #60 on: January 14, 2018, 02:22:56 AM »
Be aware Tequipment offers a discount to EEVBlog members. Also they have a clearance section for returned scopes resold at a slight discount, might be missing some packaging etc. you might get a 1054 for less than $300! But not by much :)
« Last Edit: January 14, 2018, 02:26:07 AM by Old Printer »
 

Offline nealfox

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Re: Scope Purchase
« Reply #61 on: January 16, 2018, 12:55:59 AM »
I ordered the Rigol DS1054Z from TEquipment.NET yesterday. The cost after the EEV Blog discount was $328.06 and it includes the software bundle.
 


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