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View Full Version : Looking for Oscilloscope recomendations



Sienna
02-22-2009, 09:50 AM
I am looking for a 100MHz (minimum) capable oscilloscope and preferably a logic analyzer too. I don't care whether its PC based or standalone.

If it has a logic analyzer, it should support the standard protocols (serial, SPI, I2C). If it is PC based, it should be able to run on Vista x64.

Thanks for any recommendations!

ScuD
02-22-2009, 09:57 AM
I would recommend getting a separate LA and oscilloscope.
Most oscilloscopes with built-in LA function lack a lot of protocol decoders and I feel the steep price climb isn't justified over the two separate.

For the scope I'd go for a Rigol, check Ebay to get a cheap one. These can be compared to the lower-end agilent scopes (hardware is the same, but agilent has some patented firmware in theirs)

For the LA, I'd get the Intronix Logicport http://www.pctestinstruments.com

Good luck on the hunt!

Adrenalynn
02-22-2009, 10:25 AM
eBay, eBay, eBay.

Agilent, HP, Tek.

I picked up a 100Mhz HP digital storage scope with printer and computer interfaces for $150. Another $99 to have it recertified.

My color 1Ghz scope was under $600 + 200 to have it recertified.

LA - Gould is another brand to look at. I've been using them since C was a child. ;) I picked up a 16 channel Gould for $499 + $275 for recert. Let me know if you need a reasonable NIST traceable certification lab.

No0bert
02-22-2009, 04:05 PM
Sorry to jack the thread, but what is "recertification?"

lnxfergy
02-22-2009, 04:22 PM
Sorry to jack the thread, but what is "recertification?"

The information you get from your scope is only as good as the scope is... Like any other measuring tool (especially electronics ones), a scope can get out of calibration. When you get a new scope, it is always a good idea to get it recalibrated/recertified that it is working properly and within specification... this is a must if you are using it professionally.

-Fergs

KurtEck
02-22-2009, 05:56 PM
For Logic Analyzer, I picked up the one from www.saleae.com (http://www.saleae.com) for $150. Only 8 channels, but does what I need.

Kurt

Adrenalynn
02-23-2009, 12:25 AM
Yup! at what Fergs wrote.

Beyond that, you is recalibrated against standards and finally, if you need it, you can get a certification from a NIST (National Institute of Standards and Technology) traceable lab, meaning that the tools and methods are compliant with NIST standards and they are certified to be making the recalibration and certifications. If you're using it professionally, or to defend academically, NIST-traceable certification is a must along with a certificate and seal. That generally costs more, and you can have a NIST-traceable lab recertify the device without paying extra for the certificate and seal.

tom_chang79
02-23-2009, 12:54 AM
My color 1Ghz scope was under $600 + 200 to have it recertified.


/jealous

The line between an oscilloscope and a spectrum analyzer is being blurred with majority of the component in the newer test equipments being a PC and a very fancy DSP subsystem . However, if you only need to be in the time domain, a good sturdy scope in my opinion is the:

Tektronix TDS2000B

But as Adrenalynn stated, ebay is the best choice for these kinds of things if you don't want new. Many of the refurbished ones are just as good if it comes with a NIST-traceable calibration cert...

You can find the TDS2000B at Fry's if you're in need of one right away... I usually check those things out at Fry's when I'm trying to shake one of those pesky salespeople off my back :wink:

There are some PC-based oscilloscopes nowadays. Check out the latest issue of Robot Magazine for some ads in there. They do some basic stuff like SPI, I2C stuff, but I'm not sure if the bandwidth of those PC based ones can support beyond 100MHz...

Make sure you get some high frequency scope probes if you're going to check those out. Many lower priced scopes often come with low speed scope probes (higher capacitance). If you really need a high frequency scope probe (for scopes like say that 1GHz model that Adrenalynn has), you need to build yourself a shop-built-probe which basically loads the test point down resistively (at the probe) which cuts down your resolution of accuracy but it does allow you to see a more-accurate rise-time.

A good guide book that I love to use both in the digital (time) and frequency domain (analog/RF) is this book:

Amazon.com: High Speed Digital Design: A Handbook of Black Magic (Prentice Hall Modern Semiconductor Design Series' Sub Series: PH Signal Integrity Library): Howard Johnson, Martin Graham: Books

This was the book that we used in one of the courses I took as an undergrad, appropriately, "High Speed Digital Design" which was an RF Engineering course disguised to fit in a Computer Engineering curriculum.

That book has many practical techniques and concepts, such as building a shop-built probe (as I stated above), measurement techniques, effects of rise-time measurement from oscilloscopes, routing technique, transmission line theory, and etc...

But rest assured, if you're only measuring up to 100MHz, things are pretty "behaved." In the world of RF, I usually say "things starts to get squirrly beyond VHF (230MHz) and things are REALLY squirrly at UHF and beyond (470 to 860MHz)" :tongue:

Sienna
02-23-2009, 05:04 AM
ebay and expensive electronics scare me. Plus I got burned enough when I was looking for a simple 8" studio monitor.

I was thinking more about my needs, and I think that a logic analyzer like the one Scud posted would fit my needs a lot more then an actual o'scope. I looked at the Saleae's, but their software doesn't seem to like Vista x64. I also looked at a MSO-19 (IIRC) and that software I didn't like the interface of.

Thanks for the input everyone!

KurtEck
02-23-2009, 09:48 AM
Don't know how well the saleae's 64 bit software works, but they do list is under their download page.

Kurt