Break Points
An MSO for the masses
Jack Ganssle
3/1/2010 6:00 PM EST
I love my job. In addition to meeting lots of really interesting engineers who are creating the next wave of innovation, vendors send me their latest wares for a look-see. Most, of course, are hoping to get some free ink to help promote the product, though I rarely do product pieces. But a few of the goodies are cool enough that I think there's value to the readers of this magazine for an unbiased review.
Tektronix sent me their MSO2024 MSO recently. I've been a fan of Tek scopes since first using them 40 years ago while in high school. My dad worked for a start-up space company, and we kids were required to provide free janitorial duty on weekends. But that did give me access to the lab, which had a number of hulking vacuum tube-based Tektronix scopes firmly seated on caster-equipped carts.
The company had a number of 545s. Those units were like all of the Tek scopes of the era: massive, reliable, sporting a panel covered with a sea of knobs, switches, and levers, all to draw a couple of traces on a five-inch screen. Pull the access covers and you were presented with a wonderland of truly beautiful electronic and mechanical engineering. The time base selector switch, for instance, had a fabulously machined mechanism to propagate a hard twist of the knob into the scope's bowels.
Tektronix was long-heralded for their engineering, and a succession of improved scopes kept coming to market. Perhaps my favorite was the 7000 series that had sci-fi looking illuminated clear plastic pushbuttons to control many functions. We bought a lot of these at the company where I worked in the 1970s. Their quality polished the Tek name. (Editor's Note: See Jack Ganssle's column from April 2007, "The Modern Oscilloscope" about Tektronix's 511.)
The MSO2024 is a another quality Tek product whose major flaw is that the company wants the demo unit back. Maybe it'll get lost in shipment. Or the 75-year-old technophobe next door might sneak in at night and steal the thing. Surely there's some story I can concoct that Tek's marketing folks will believe.
 Tektronix's MSO2024--See ESC's website for info on the giveaway of this scope at the Embedded Systems Conference in April 2010. Click on image to enlarge. |
The MSO2024 is very different from the 545 and 7000 series. As has become standard in this product sector, the CRT has given way to a flat-screen display, which greatly reduces the depth of the instrument to about 5 inches. Scopes no longer ask for a serious commitment of bench space. At eight pounds, it's as easy to move as a laptop.
As the name implies, this is a Mixed Signal Oscilloscope, which is a hybrid of logic analyzer and traditional o-scope. In the case of the 2024, there are four analog vertical inputs plus a 16-channel logic analyzer. An MSO can display any mix of digital and analog data at the same time. Key to the magic of an MSO is that any input can trigger the sweep. Want to see the output of a programmable gain amplifier when the software commands a gain of 8? Hang the logic analyzer probes on the amplifier's digital gain input, an analog channel on the output, and trigger on 1000b. Since embedded is the intersection of hardware and software, I've long thought that an MSO is an indispensable piece of equipment.
|
|
|
|
|
bcarso
3/10/2010 11:07 AM EST
Great review! I am pleased to have followed Tek since I ogled the ancient catalogs as a teenager and wished I could have all of the stuff (this was back when they had dual-beam scopes, and the 519 with direct CRT plate drive). Then I used a 535 for years at UCLA, until finally some unspent year-end money popped up and I got a 475 and FET active probe, for a dramatic improvement in bandwidth and sensitivity.
Then I bought a 2236, with counter-timer-multimeter (including access from the Ch. 1 probe tip) for about 3k in 1985, and although some inevitable deterioration has set in, still serves. Based on 2010 dollars the 5400 asked for the scope reviewed is really a good deal.
There were some dark days at Tek, when they sent a lot of old-timers home and made some truly execrable scopes---I remember one that didn't even allow one channel to be triggered from the other! But eventually things righted themselves and they got back to engineering excellence.
Sign in to Reply
ESD editorial staff: SRambo
3/11/2010 9:09 AM EST
A reader comment:
Great review! I am pleased to have followed Tek since I ogled the ancient catalogs as a teenager and wished I could have all of the stuff (this was back when they had dual-beam scopes, and the 519 with direct CRT plate drive). Then I used a 535 for years at UCLA, until finally some unspent year-end money popped up and I got a 475 and FET active probe, for a dramatic improvement in bandwidth and sensitivity.
Then I bought a 2236, with counter-timer-multimeter (including access from the Ch. 1 probe tip) for about 3k in 1985, and although some inevitable deterioration has set in, still serves. Based on 2010 dollars the 5400 asked for the scope reviewed is really a good deal.
There were some dark days at Tek, when they sent a lot of old-timers home and made some truly execrable scopes---I remember one that didn't even allow one channel to be triggered from the other! But eventually things righted themselves and they got back to engineering excellence.
bcarso
--originally posted on Planet Analog
Sign in to Reply
ESD editorial staff: SRambo
3/12/2010 9:40 AM EST
A reader comment submitted via e-mail:
I've just read "Remembering the Memories" (Break Points - January/February 2010) by Jack Ganssle. His description of computers that used drum memory brought back some personal memories. My first computer, which I programmed in the summer of 1961, was an IBM 650. It had 2000 (decimal) words (10 decimal digits plus sign) of memory arranged as forty tracks of 50 words each. The heads were fixed (not even floating) and the 6" diameter drum rotated at 12,000 RPM. This arrangement caused some thermal issues when stopping and restarting the machine. Obviously, you didn't want head crashes during warm up. This meant that, after the drum stopped and while it was cooling, the drum and heads came in contact so that restarting would be disastrous.
Two additional drums were optional, as was a small amount of core memory (perhaps as much as 100 words). Another optional accessory was the RAMAC disk system. Unfortunately, I don't remember the capacity of RAMAC system.
Efficient programming was a real challenge. In order to avoid excess latency in accessing instructions, each instruction specified the location of its successor. In the case of branch instructions (all presumably conditional), each instruction specified two possible successors. Program loops were usually points at which instruction-placement optimization was relaxed, but such loops could be unrolled to minimize the loss - if you could afford the memory for the duplicated code.
There were table look up instructions that could search entire tracks in a single revolution. This was a great boon under the circumstances.
On the two 650's I used, all input and output was via punched cards, although I believe that a line-printing device might have been optional.
I still have one or more original manuals for this computer and the peripheral devices with which it was used.
Ron Martin
Ann Arbor, MI
Sign in to Reply
ESD editorial staff: SRambo
3/12/2010 9:52 AM EST
Ron, thanks for the write-up. Two whole generations have missed the vacuum tube era and take cheap computers for granted. When I was in college we had access to the campus' one machine (though only special people could ever actually see the thing), but no one could even dream of owning any sort of computer. How things have changed!
All the best,
Jack
Sign in to Reply
zhgreader
3/21/2010 9:27 PM EDT
is it expensive?
Sign in to Reply
zhgreader
3/21/2010 9:46 PM EDT
[Maybe it'll get lost in shipment. Or the 75-year-old technophobe next door might sneak in at night and steal the thing. Surely there's some story I can concoct that Tek's marketing folks will believe.]
surely, I like this words very much. next I will make up a smme story to get a tek instrument.
Sign in to Reply
Sixtwenty
3/17/2011 12:47 PM EDT
Have to differ somewhat with the conclusions here. I've been using one of these for some months at work and find it the most annoying scope I've ever come across during 25 years in the business. For a start it takes MUCH too long to boot up for no good reason. And everything you do splatters annoying menus over the small screen which get right in the way of the traces. I spend half my time with this scope pushing the "menu off" button to remove garbage from the screen. Also the traces interfere with one another, if one trace has HF noise spikes it tends to obscure what other traces are showing. The cursor function is annoying and splatters its own obstructive menus over the traces you're trying to measure. If more than two traces are in use then the channel status window expands so that it permanently blocks part of the trace window. And so on.
All in all I get the impression that the sodware (intended) was written by a windows programmer who's never developed electronics or had to use a scope in anger.
This instrument is annoying to use and I fear Tek have lost their way and let inexperienced firmware designers loose on this project. Hopefully later updates will improve these annoying shortcomings.
Sign in to Reply