why do they still make analog oscilloscopes

[KedasProbe]

They still make analog scopes so DSO designers have a reference about how the signal is supposed to look like on the LCD sceen

[fcb]

why do some manufacturers still make analog oscilloscopes

simple - because people buy them

[zapta]

When you think about it, all oscilloscope are analog. The voltage vs time graph on a digital scope is still analog (compare with a analog vs digital multimeter where the display of the later is indeed digital).

[KedasProbe]

When you think about it, all oscilloscope are analog. The voltage vs time graph on a digital scope is still analog (compare with a analog vs digital multimeter where the display of the later is indeed digital).

It's a DSO because the signal is processed digitally.
Holding your tong on the VGA out cable of a DSO still doesn't make it an analog scope 

[zapta]

It's a DSO because the signal is processed digitally.
Holding your tong on the VGA out cable of a DSO still doesn't make it an analog scope 

The time and voltage representation on the display in a graph form is analog.

[VK5RC]

As a good digital scope fan,  I would propose 'all scopes are digital " as photons, eye photo-receptors,  the optic nerve and neurons are all binary or quantized.
Please don't take this too seriously :-)

[T3sl4co1l]

As a good digital scope fan,  I would propose 'all scopes are digital " as photons, eye photo-receptors,  the optic nerve and neurons are all binary or quantized.
Please don't take this too seriously :-)

The phenomena may be quanta, but the probabilities aren't even analog, but complex numbers!

Tim

[dannyf]

Please don't take this too seriously :-)

But your analysis is spot on.

[echen1024]

They still make high-end Tektronix 2465 cotemporaries as well.
The Iwatsu SS-7847, 470MHz analog scope. A steal at only $17k
http://www.tequipment.net/IwatsuSS-7847A.html?v=7402

[Jay_Diddy_B]

Hi,

If I could only have ONE scope I would chose either a Tektronix 2232 or a Philips Combiscope.

Both of these can operate as either analog scopes or digital storage scopes at push of a button.

I like the analog mode for trouble shooting and the digital mode for measurement. These are advance analog scopes with readout and cursors.

I started with a Tektronix 545 tube scope. I was given this as 'BER' Beyond Economical Repair, I bought a parts unit to get some  spare tubes and a got it working.

This scope had a 4 x 10 cm graticule. The 545 was built in 1955 and 1959. I was given it in 1979.  Tektronix scopes built before the mid-60s had UHF connectors (PL-259 , so-259). This 545 scope features like dual-timebase, intensified sweep. The bandwidth was 24 MHz with a CA dual input plug-in.

The next scope that I got was  an HP180 mainframe with 50 MHz plugins. I like the flood gun illumination on the HP scope, great for taking polaroid photographs.

After this I graduated to a Tektronix 7603 with 7A26 and 7B53 plugins. I also bought a 7D20 digitizer for this mainframe. 40Msps and 70 MHz BW. I did a lot of good stuff with this scope.

I have had nearly all the models in the 7000 series. I have had TDS460, TDS 500 series and TDS 700 series.

These days I typically have a TDS 744A or a TDS 754A scope on a  my bench.

I think the analog scopes are great for academic use, where the waveforms are continuous. A soon as you need to look at single shot events then digital is definitely the way to go.

Regards,

Jay_Diddy_B

[David Hess]

I agree about the 2232 (or 2230).  Those are my go-to oscilloscopes for general work and they have peak detection which the low end Rigols still lack.  When I need real frequency and pulse measurements that may or may not be gated, I break out the 2247A or 7D15.  When I need automatic measurements, a pretrigger record, low repetition rates, or waveform storage, then I use a DSO although the 2232 can do all of that except automatic measurements.

For everyday use, I wouldn't trade any of these mentioned above for a new rigol or even one of those Tek junk scopes with 2kB of CCD-memory. Reasons for that are:
-Instant beam, no boot time, no stupid menus, there's a knob for everything so much faster to use
-you see what's really there no ADC artifacts, aliasing or undersampling
-usually displays and triggers on signals well beyond their specs, do that with a digital one
-analog stuff is relatively easy to repair and rarely fails compared to (new) digital circuits and I like to keep my equipment working myself, furthermore the documentation is usually excelent compared to new equipment
-a plugin for about everything in the 7k series like the 7A13 (my everydays favorite since it combines voltmeter and scope); ADC for slow non repeating signals (7A22) in the 7854

The Tektronix CCD oscilloscopes or at least the early ones with peak detection are pretty good and compare favorably with modern "low noise" DSOs once you get past their non-graded displays.  I would prefer a short record length with higher waveform acquisition rates than a long record length although the Tektronix CCD designs are slow.  Where they suffer is aliasing caused by interleaving of the digitizer but modern DSOs also have that problem to one extent or another if they are implemented that way. 

The user interface is generally better; I do not have room on my workbench for another keyboard and mouse.  They show a more realistic representation of the signal without a bunch of different modes with inadequate documentation.

I like the 7A13 because it is a great differential input amplifier with slideback capability which puts modern DSOs and most differential probes to shame.

As far as the noise issue goes, look how much trouble Dave had to go to to compare them.  That is *not* an advertisement for ease of use or understanding of DSOs.  Even worse, too many low end DSOs lack intensity grading which both makes them look worse *and* make them useless for measurements where visual noise matters.  The ones that do support intensity grading often do a poor job of it.

[Stonent]

Some people still prefer the analog intensity graded display and no-fuss operation, and hiding all that uncorrelated noise 
Obviously a market for them.
Perhaps still some education market left too? Old time teachers who think it's best to learn on an analog. I don't blame, I think they are still excellent learning tools.

It took me almost a day to something to show up on my analog scope when I first got it.  I thought it was dead.  No auto button to do it all for me.

I suppose if you're used to auto trigger, auto time-base, auto volts/div. You could miss when the scope just "autos" something and make a wrong measurement.

[T3sl4co1l]

AUTO button!  Scourge of the engineer!  I am highly tempted to remove them, particularly the most accidentally-touch-prone ones, in the most physically gruesome way possible!

Tim

[David Hess]

My 2440 (DSO) and 2247A (analog) have automatic setup buttons but the only time I use them is to reset the oscilloscope to a known state.

[zapta]

As a good digital scope fan,  I would propose 'all scopes are digital " as photons, eye photo-receptors,  the optic nerve and neurons are all binary or quantized.

If your eyes only count the total photons then yes but they also assign x/y values to each photon which represent time and voltage respectively.

Please don't take this too seriously :-)

Too late.  ;-)

[VK5RC]

Re x-y data,  that is also digitalised in humans as the photoreceptors 'pixelate" (i am sure that is not the correct term)  the data in the x-y plane as well!  The post data processing in the occipital lobe is the clever bit! One "you beaut"  fpga multi_channel processor :-)

[zapta]

Re x-y data,  that is also digitalised in humans as the photoreceptors 'pixelate" (i am sure that is not the correct term)  the data in the x-y plane as well!  The post data processing in the occipital lobe is the clever bit! One "you beaut"  fpga multi_channel processor :-)

If so, I have a digital oscilloscope for sell  ;-)

[madshaman]

AUTO button!  Scourge of the engineer!  I am highly tempted to remove them, particularly the most accidentally-touch-prone ones, in the most physically gruesome way possible!

Tim

Seriously?  What's wrong with hitting auto and twisting a knob or two twice instead of twisting a knob or two a bunch of times.

Honestly, I can't imagine anyone who knows how to use a scope becoming reliant on auto-scale...

Why would you remove a useful feature?

[electronics man]

I never use auto on my DSO i have no need to.

[John Coloccia]

How do you find an unknown signal without the auto trigger?  Do you just randomly twist knobs until you see something blip on the screen?  It seems like a pretty useful and practical function to me.

[c4757p]

How do you find an unknown signal without the auto trigger?  Do you just randomly twist knobs until you see something blip on the screen?

Randomly? No. How often is a signal truly unknown? I'd rather know the scale factors the scope is set to without having to stop and read them. I've usually got a pretty good idea what kind of signal I'm going to be looking at, so I set up the scope before I start. Then I can zoom in or out if I see something interesting.

[John Coloccia]

How do you find an unknown signal without the auto trigger?  Do you just randomly twist knobs until you see something blip on the screen?

Randomly? No. How often is a signal truly unknown?

When I'm debugging a board that doesn't work, quite often actually.  I can have a tiny little AC signal...or I can have something sitting on a rail....or anything in between.  I'm baffled why a pro would waste time twiddling around when you can simply zoom out, hit auto, see what you have, and then zoom right in on it with proper triggering.  Considering all the beginners on this board, it seems like it's doing them a disservice by filling their heads with the idea that auto triggering is somehow bad or amateurish.

[w2aew]

How do you find an unknown signal without the auto trigger?  Do you just randomly twist knobs until you see something blip on the screen?  It seems like a pretty useful and practical function to me.

Remember that auto-trigger does automatically setup the trigger setting for you. It is simply a timeout circuit. If a valid trigger event is not found in 50ms or so, it initiates a trigger on its own. This keeps the trace active while you hunt for your signal.

So, auto-trigger is very useful, and not in the same category as the Autoset feature. Autoset attempts to change vertical, horizontal and trigger settings to put a waveform on the screen.

If you didn't have auto-trigger, you could use something line trigger to keep a waveform triggered on screen so that you could set the vertical controls properly on your signal, then switch the trigger source to the channel of interest.

[madshaman]

Auto-set (depending on your scope) can do more than just setting the time-base, triggering and scaling.

For example, if I've been using two channels and moving things around, then I hook up four channels, I just have to make those extra channels active then hit auto: all four traces are scaled, ordered and moved such that they're lined up from top to bottom, all the same size.  It would take forever to do manually and would just be a big pain in the butt.

Sure, afterwards I might have to change the trigger source, type, params etc. but I'd have to do this anyway.

[T3sl4co1l]

How do you find an unknown signal without the auto trigger?  Do you just randomly twist knobs until you see something blip on the screen?  It seems like a pretty useful and practical function to me.

Noooo!  Auto trigger is actually useful!

Although if you're working on NORM, you can tap the FORCE TRIG a few times to get something up to date.  Often easier than switching it to AUTO and tweaking an encoder.  Not like flipping a switch and turning a pot on a '475.

Tim