PC Based Oscilliscopes

Depending on what you are trying to measure, they can be a very usefull tool. A "real" scope is much better, but much more expensive. IF you can, try before you buy. At the very least get to do a hands on demo. I use several different audio applications for a variety of my measurement needs. For the serious stuff, I borrow a good scope from work. The biggest "flaw" is they average the readings, so if what you are looking for is a rarely occuring gltich, a most PC scoes will miss it. For looking at normal waveforms they do a respectable job.

Terry

This one is free. It's only 20khz, though.

100Mhz. Price?

Scope and logic analyzer..

mike

My gut reaction when I see a PC-based O-scope is to cringe.

I would stay away from them. For the same price range that you mention, you could get one heck of a nice Tektronix 7000 series 'scope, or perhaps a 400 or 2400 series portable, all from the used/surplus arena (more specifically, from ham radio swap meets or Greed-Bay).

Example: The Tek 7603 was one of their most popular, and is also one of the most plentiful on the surplus market. It has a mainframe bandwidth of at least 100MHz, and can often be found for around $50-$100 with plug-ins.

If you want some serious bandwidth, you should have a look at the Tek 7904 or 7104. The base frames have bandwidths of 500MHz and 1GHz, respectively, and you should be able to get a good 7904 with plug-ins for a little over $300.

Your test equipment needs are, of course, your choice. However, I would like to say that just because a test instrument CAN be designed to work in a PC environment does NOT always mean that it SHOULD be. Good- quality input stages are hard to do (there's a reason Tek put so much R&D into theirs), and they are one of the main driving factors where cost is concerned.

I have little faith that the Taiwan-import PC-based (alleged) O- scopes can do a proper job in this regard. Good quality test gear is an investment, and it should be treated that way.

Keep the peace(es).

There's one major advantage to the PC based scopes. It's STORAGE of waveform. When I was younger we had to put a hood over the front of the scope and use a Polaroid to get shots of easy to miss signals.

A real storage oscilloscope costs a fortune, but if you can get a PC variety that fills your frequency needs, I'd go for it. Three or four hundred bucks is a bargain when accompanied by a good warranty..

mike

Good post you Canuck!! Your all right tech wise :)

Some of them aren't too bad, although in the $200-300 range you'll not get any record setters. For one data point, though, some of the higher end scopes do use Windows as their user interface. Check out Tek's TDS6000B at

For one possiblity closer to your price range, take a look at I have not used their o-scopes but I have (and use) one of their PC-based logic analyzers. Been reasonably happy with it.

I love damnation by faint praise. It's a good thing you haven't heard me trying to practice this bass. You'd retract that

EADG EADG I mean. sheesh..how hard can it be? I'm starting to suspect they shipped the wrong instructions with it, not that it matters, I can't speak Chinese anyway.

mike eadg eadg

They are too limited to be worth the money. Get a used Tek in good working order in that price range, as another poster mentioned.

Ed

Tektronix DSA602A Digital Signal Analyzer. All kinds of waveform storage and analysis, and a floppy drive as well. Runs about $400-$500 on the used market, uses 11-series plug-ins, mainframe bandwidth of

1GHz.

And how long will it last? If it's made up entirely of custom parts, and cannot be repaired by the end user (at least at the module level), then I would hardly think of it as a good investment.

When I buy test equipment, I expect it to be serviceable for a MINIMUM of ten years. Very few items that I've bought new have measured up to that requirement.

You make some valid points, but I still have concerns. Tektronix, among many others, has been known to use proprietary chips/components in their scopes. These may be getting hard to get. That would tend to even out the decision making process, all other things being equal.

Having said that, Tektronix stuff is very nice, quality made merchandise. I'm admiring a 7B92A dual time base module even as we speak. I just don't want to wind up like Hamlet...

Alas, poor 7904, I knew it Horatio...

mike

Thanks for all the input, I am going to pass on the PC stuff and shop EBay and ?? for a good used scope. Any recommendations other than EBay?

My personal preference is a conventional benchtop scope for high frequencies, and a sound-card-based PC scope for audio work. I use my own Daqarta shareware for the PC scope (shameless plug). It only runs in real-mode DOS on old ISA-bus systems with Sound Blaster cards (or lab-type boards, which are pricey). I run an old cast-off 16 MHz 386 system that works just fine for this purpose.

The PC gives me real-time spectral analysis, which is great for distortion measurement and especially for distortion adjustments. Another big advantage is that the PC can generate complex test signals and keep them exactly in sync with the input signal that is responding to those signals, so you can use signal averaging to measure noise *way* below the noise floor.

Windows-based version is under construction, but won't be released for several months yet.

Hope this helps!

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

Try looking for used equipment from leasing companies.

Also look for plant closings that may result in equipment sales or auctions.

craigm

There are several places around the internet that sell reconditioned test equipment. You might end up spending a bit more than at ebay but you (should be) getting something that has been cleaned, op tested, and has all of its parts. Possibly also a better warranty.

There are a jillion out there, but a couple that I get periodic catalogs from are:

< Top-posting corrected. Please don't top-post! See this link for the reason why:

Sure. Check

for hamfests in your area. They happen all over the country (heck, all over the world) at various times during the year, and the swap meet portion of any hamfest bears (usually) a 95% or higher focus on electronics in terms of test gear, radios, computers, etc.

If you've never been to such an event in your life, I would (SHAMELESS PLUG ALERT) take a look at an article I wrote on my own page at this link:

This is a guide to scrounging at both surplus places and swap meets. I hope you find it helpful.

Happy hunting.

It is very rare for a cross posted article to RRS to be useful. Most are Trolls. I enjoyed your web page on scrounging. I'm taken aback on the prices that you posted about equipment however quoted below.

A TDS7104 sold new in the $30K to $40K range depending on options. I have priced this scope at used equipment resellers in the $8 to $10K range. The equipment is sold in calibration and working with a short warranty like 30 days for verification that the equipment is in proper working condition from resellers.

At prices under $1K even with no guarantees I expect this equipment is hot at those prices. All equipment from the major makers have serial numbers throughout the equipment and in the firmware. If you ever send this equipment in for repair you might be in for an unpleasant surprise.

In the last few years there is a new class of scope called real time. The reason I'm responding to this thread is that you just happened to mention a real time scope the TDS7104. Tek calls real time scopes DPO or Digital Phosphor scopes. Most digital scope are repetitive sampling making them a poor choice for low frequency events like an intermittent pulse and these are useless for high speed single shot events. The DPO's resemble an analog scope with memory. There are the best suited digital type for single shot or low frequently occurring events. The DPO's are designed for a very high re-acquisition rate compared to digital sampling types, which is why they are better suited for the low frequency events as they are more likely to be actually sampling the input during an event rather than being in another part of the processing cycle. DPO's have a rapid processing cycle and also have most of that cycle being actual sample time so they are able to catch that infrequent pulse. The repetitive sample high speed scopes generally have cycle times of 200KHz or slower and most of that cycle time is signal processing and display. Repetitive sampling scopes are good at any type of recurring signal like clocks. They are poor choice at looking at data streams with long patterns. The only way you can look at long patterns is at the bit level or eye mode.

SNIP

No, he didn't. He was describing the Tek 7000 series mainframes and plug-ins, NOT any of the TDS series scopes. There are many years, and a world of difference, between the two.

Ed wb6wsn

Sorry about that. That sort of thing happens when manufactures reuse numbers.