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Advice on entry level oscilloscopes
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Author:  tomaitheous [ Mon Dec 19, 2016 12:52 pm ]
Post subject:  Advice on entry level oscilloscopes

It's been a while since I've been looking at entry level scopes. I remember this site: http://www.bigmessowires.com/2013/09/23 ... lloscopes/
And that the Owon SDS1702 seemed like the best for what it offers. Amazon has it for $368 new. The review is a bit outdated by now. Is there something equivalent to the 1702 in the $400-$450 range with a little more memory than 10mpt of this model (at full speed)? Or is that pretty much the top-end for entry level scopes?

Author:  Memblers [ Mon Dec 19, 2016 10:20 pm ]
Post subject:  Re: Advice on entry level oscilloscopes

I'm no authority on the matter, but it seemed like when I was looking, ones in the same price range seemed similar in features. I went with the Rigol DS1054Z as my first scope and I've been happy with it. I suppose you've heard about people cracking its locked features, not something I've felt the need to do, but one of those paid options is to double the sample memory to 24Mpts.

Author:  Bregalad [ Tue Dec 20, 2016 12:45 am ]
Post subject:  Re: Advice on entry level oscilloscopes

Rather than buy an "entry level" new oscilloscope, why not get an old professional scope used for an equivalent price ? That sounds like a much better deal.

You might also be interested in the picoscope, basically it's a piece of soft/hardware that uses a laptop as an oscilloscope.

Author:  tomaitheous [ Wed Dec 21, 2016 12:54 pm ]
Post subject:  Re: Advice on entry level oscilloscopes

Thanks for the feedback guys. I'm still struggling with shelling out $400 (the USB one with the feature I would want is $380) for a scope. Trying to justify it, when I'm on a limited budget for school. It's not that I can't afford it per se, but should I waste the money on it. I don't *need* a scope right now - I just want one haha.

Author:  Garth [ Wed Dec 21, 2016 1:14 pm ]
Post subject:  Re: Advice on entry level oscilloscopes

The following is from the oscilloscope section of the "Basic Workbench Equipment" chapter of my 6502 primer.

    An oscilloscope is not an absolute necessity, but it's awfully good to have. If you can afford one, then it's a necessity! :D Basic new ones seem to start around $350. It needs to be at least dual-trace, triggered, and 20MHz. Basic stand-alone 'scopes now seem to meet all of those, in fact start at 40MHz or more which is good. Pocket digital ones made for audio probably will not do you much good for your home-made-computer hobby. One thing I will insist on is that you get a good pair of probes, and use them in the x10 switch position. In the x10 position, the oscilloscope's .1V-per-division setting becomes 1V per division, and so on; but probes are never any good for the higher speeds in the x1 position! If you buy a new 'scope, it will come with probes. Take care of them, because they're not cheap to replace. There's a lot more to good probes than meets the eye, and a decent pair for a low-end oscilloscope will cost you at least $40 or $50. (They can be many times that price for the faster 'scopes!) If you get a used 'scope, either be sure you get good probes with it, or budget some money to buy some.

    Dave Jones has a rant about oscilloscopes on his EEVBlog #86, and frankly, he's right. His basic message in this one is that cheap 'scopes like the DSO Nano are worthless; and after seeing his review of it, I totally agree! His recommendation—actually his pleading, after all the times he's been asked about the cheapie 'scopes—is that if you're on a tight budget, then get yourself a used, basic 20MHz dual-trace triggered oscilloscope which you can sometimes even get for free these days. I came across this video review of an oscilloscope attachment and ap for the iPad or iPhone on EEWeb, which I mention because like so many of these that seem to be a nice shortcut way to get something we used to have to pay a lot more for, they say it's very nice to use but its technical specifications are very poor, with only one analog channel, 5MHz bandwidth, 500mV/div with the probe on x10, and a 240-sample screen, which are not adequate for the work we're addressing in this 6502 primer.

    A couple of good 6502.org forum topics on oscilloscopes are:
    Cheap oscilloscope and other test equipment and
    Recommended oscilloscope features?

Author:  lidnariq [ Wed Dec 21, 2016 1:35 pm ]
Post subject:  Re: Advice on entry level oscilloscopes

Garth wrote:
His basic message in this one is that cheap 'scopes like the DSO Nano are worthless
It's definitely vital to distinguish between the "It's actually a sound card" tier and the "a real 'scope" tier; the DSO Nano's sample rate (1MS/s) and corner frequency (200kHz) illustrate that.

But as far as the OP's asking for advice about number of samples in memory at a time? My by-now-ancient DSO has a paltry 2.5Ksamples, and I've only rarely found myself needing "a little more" on either side. On the other hand, I'm certain if I had more I'd use it...

Author:  TmEE [ Wed Dec 21, 2016 2:35 pm ]
Post subject:  Re: Advice on entry level oscilloscopes

I have found large trace memory to be pretty much useless. I can see it useful for looking at some bus signals but logic analyzers work muuuuuch better for that and cost way less.
Lots of analog bandwidth (100MHz+) and 2 or more inputs is the main thing for me, other stuff such as tiggers, high sample rates and other niceties are found on pretty much all scopes you can get except for those really cheap things mentioned earlier.

Author:  tomaitheous [ Wed Dec 21, 2016 10:33 pm ]
Post subject:  Re: Advice on entry level oscilloscopes

The first thing I want to look at, is video. I was told at least 5x the frequency of what you're looking at. I'll be looking at video in the 5.369mhz to 10.79mhz range, so I guess 50mhz the lowest limit for me. 70mhz would nicer, 100mhz ideal (even if I don't use it). And yeah, I'd love to get a logic analyzer too, but I don't need it right this second. 10mega-samples is probably the minimum (more would be better; ideally I want to capture multiple scanlines, but I guess I can configure a delayed trigger for that).

Author:  lidnariq [ Wed Dec 21, 2016 10:44 pm ]
Post subject:  Re: Advice on entry level oscilloscopes

If you can get away with a 24MHz/8 channel or 12MHz/16 channel logical analyzer, the LCsoft prototyping board can be had for cheap, and is supported nicely by sigrok.

If you want more channels or more sample rate, a friend was pleased by the LA1034

If used is an available option, the '90s HP logic analyzers are amazing for debugging 68k-based systems.

Author:  tomaitheous [ Sat Jan 14, 2017 9:15 am ]
Post subject:  Re: Advice on entry level oscilloscopes

I ended up buying the Owon SDS1702 "used but like new" for $260. Now I'm researching for USB logic analyzer. Something cheap in the 50-100mhz range with at least 8 channels - $100 or less.

Author:  tomaitheous [ Sat Jan 14, 2017 9:19 am ]
Post subject:  Re: Advice on entry level oscilloscopes

lidnariq wrote:
If you want more channels or more sample rate, a friend was pleased by the LA1034
.

The site says "timing-state", so it has both modes right? (I assume it would. I'm a totally new to logic analyzers)

Author:  lidnariq [ Sat Jan 14, 2017 12:29 pm ]
Post subject:  Re: Advice on entry level oscilloscopes

"Timing-State Logic Analyzer" appears to be borrowed without context from this Agilent document.

Reading through Agilent's document, that tentatively looks like it just means "internal or external sample clock", but I could be misunderstanding.

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