New Digital Tek Scopes

I've been fooling around with the Tek TDS 2012. It is an odd change, for the die-hard user of analog scopes. There is a moderate learning curve and a moderate expectation curve.

The first thing that strikes you is that the screen resolution is only 320 x

240, so that "jaggies" are evident much of the time. However, you learn to work around that by choosing appropriate scales and values. The other major surprise is the issue of record length, which isn't an issue at all in an analog scope. The record length in the TDS 1000/2000 scopes is only 2.5k. If you are just looking at waveforms there is no problem, but looking at something like a modulation envelope is a different story.

On the plus side, the inherent storage feature and the ability to capture even fast single shot events and see them at full brightness is a real treat. The built-in FFT function doesn't hurt either. The ability to see pre-trigger events and the ability to make accurate measurements is also great. I do like the "analog" interface, knobs for the common settings instead of menus.

Something I wasn't expecting is the limited dynamic range of the CH1 + CH2 functions. The math is done on the screen image data, rather than the actual sample data. If one or both of your samples create an off-screen display, the add and subtract features use the screen data rather than the signal data and some odd things result. For example, you could not use the Ch1 - Ch2 feature to view differential data in the presence of a large common mode signal. While all scopes have substantial limitations in this regard, most have a dynamic range considerably in excess of the screen size, but these do not!

One thing I DO miss is the ability to do composite triggering. You can trigger on an input, PERIOD. You can not trigger off the screen image, so you find yourself flipping the trigger selection back and forth all the time. There is also no fine adjust for the horizontal sweep speed.

To conclude, for audio work and general "fooling around," I think these are pretty good. I still have some analog scopes (Tek 547, 2225, 465) that I fire up on occasion, but no matter how hard I try to convince myself that they are better I always go back to the digital. I would sum up by saying that the TDS 1000/2000 series does many things, but does none of them exceptionally well. I use the 547 when I need the service of a differential comparator plug-in, for example. But, for the casual or non cutting edge user, they are ideal. No way would I invest another cent in a CRT scope, especially a 465/475 that is already 30 years old and has less functionality than the TDS stuff. The fact that the TDS is only as big as a telephone book doesn't hurt, either!

For audio applications, why should I shell out $500-$600 for a calibrated

465 or 475 scope that 25+ years old when I can get new for a bit more?

Are the TDS scopes Chinese crap? or am I blowing my $$$ on the old stuff?

or 475 scope that 25+ years old when I can get new for a bit more?

[word-wrap is a Good Thing, as is non-HTML posting]

In audio apps, where you're mostly looking at continuous signals, a traditional analog scope may give you a truer picture of the signal. The TDS scopes are wonderful (disclaimer: I have a TDS 220 for my home workbench, similar to the TDS 1012) but they do "suffer" from being digital (discrete) as well as a relatively low resolution display.

Discrete sampling can result in high freq signals being aliased and appearing as artifacts in the pass band. The low res display means that a pure sine wave looks a little stair-steppy up close.

On the other hand, you also get on-screen cursors and measurements, including a 2K-point FFT for signal analysis.

Summary: No, the TDS scopes are not "Chinese crap" and no, you wouldn't be blowing your $$$ on the "old stuff" either. YPYMAYTYC.

--
Rich Webb   Norfolk, VA

"Audio" wrote in news:dIvQb.108985$Rc4.768764@attbi_s54:

AFAIK the TDS scopes are NOT "chinese crap",although the power supplies are purchased parts and may have come from Taiwan,HK,Malaysia,or other places. I believe the scope PCB is still made in the US of A,by TEK,but the LCD may also come from Asia.

FYI,TEK instruments that are rebadged from other products will have a serial number beginning with a letter other than 'B' for Beaverton,like TW for Taiwan,H for Heenveren,Channel Islands.(apologies for spelling.)

--
Jim Yanik
jyanik-at-kua.net

For audio applications, why should I shell out $500-$600 for a calibrated

465 or 475 scope that 25+ years old when I can get new for a bit more?

Are the TDS scopes Chinese crap? or am I blowing my $$$ on the old stuff?

You don't hear too many jerks talk about Japanese crap these days, do you?

We are seeing low-end Chinese electronics (like throw-away DMM's) simply because we are willing to buy them. China will soon be a serious world-class electronics competitor.

You better get smarter fast.

Ed

So your telling me that if I wait a little longer I can buy a scope at Wal-mart or maybe get one free in a "happy" meal.

Ok, I'm a "smarter"....now what?

world-class

I have mixed feelings about this, though it is obviously true (that china will soon be a serious world-class electronics competitor).

On the one hand, our country is one of the cleanest in the industrialized world (if you check out a list of "most polluted cities" Beijing is high on most lists, if not at the top of it, and it is rare that a US city even makes mention), and our standard of living is similarly one of the best.

Unfortunately, this comes at a price: fewer entry/mid-level technical jobs at home, greater risk of economic hardship resulting from a war or some other political upheaval outside of our country, dollars leaving, and not really coming directly back to us, and an increased focus on mass-produced, cheaply-made, disposable, and intentionally obsolescent consumer electronics that could never be reproduced profitably by anything shy of a multinational corporation with major production facilities outside of our country.

WE are not so far off from becoming nothing but Marketing/Executive types, hospitality/food service workers and warehouse stocking personnel. Soon "made in America" will be synonymous with "insanely expensive, poorly documented, and not really all that high in quality."

That kind of scares me.

DJ Please reply to snipped-for-privacy@.spameGeniusLabs.com (remove all instances of .spam before sending)

world-class