I am able to easily remember cathode ray oscilloscopes and even vacuum tube based cathode ray oscilloscopes (sigh). I have owned four digital oscilloscopes and I love the tools they provide for digging into signals. The level of functional integration in modern oscilloscopes is impressive and I look forward to future developments. There are a few things I miss about the old CRT based oscilloscopes though.
- They didn't take 90 seconds to boot up (okay you had to wait for the heater in the CRT to warm up, but that didn't seem to take 90 seconds in my recollection).
- They never locked up or became catatonic.
- Even with digital phosphor technology, today's LCD screens don't provide the subtle detail captured by a real phosphor screen.
I doubt I'd ever go back to a CRT oscilloscope, except perhaps on a romp of nostalgia, but I think digital 'scopes both giveth and taketh away.
I guess it depends on the scope, from what I have been seeing from Dave Jones (EEVBLOG) there more than up to the task, here is part one of noise in digital scopes https://www.youtube.com/watch?v=Znwp0pK8Tzk
of course there is still the underlying question left UN-answered
I get the new scopes are way better at showing us the noise due to improved bandwidth and good sampling so we can now see the noise and can emulate the older CRT scopes mentioned above . BUT WHY IS IT NOISY IN THE FIRST PLACE if the input is shorted or terminated in say 50ohms. and the front end is of high quality, surely it should not be there ?
I think Ill start this in a separate thread, it could get interesting on its own
Yeah, I agree with Dave's argument in the video - digital scopes are just showing us what has always been there. As an "analog grey beard" I got used to the smooth, non-quantitized traces on analog 'scopes. So I may be revealing an esthetic bias more so than an objective dispute. I also agree with Dave that digital 'scopes with variable intensity are superior to those without variable intensity. However, it should be said that features like variable intensity on a digital 'scope are attempts to simulate the desirable behaviour of analog 'scopes, are they not? I have to say that Thermal Intensity gradient feature he demonstrated on the new Tektronix MDO3000 series is very cool, and is a feature not available in any analog 'scope I'm aware of. I hope Tektronix finds away to add that feature to the MDO4000 series.
Your unanswered question about why the noise is so obvious on an input with no signal is intriguing too. Could it be that the technology to sample and display broad band noise has outpaced the ability to engineer out all the stray noise sources that couple themselves into circuits? Maybe, like Galileo demonstrating that conventional wisdom was wrong about orbital relationships, we have to accept that digital 'scopes are changing our realtionship with signals.
Mark Archibald wrote:
I have to say that Thermal Intensity gradient feature he demonstrated on the new Tektronix MDO3000 series is very cool, and is a feature not available in any analog 'scope I'm aware of. I hope Tektronix finds away to add that feature to the MDO4000 series.
I'll second that.
All is about simple programming and implementing smart algorithms !!!
The "Front end" electronics just "Sample and shuffle datastreams" often with help of FPGA:s for the high demands.
The presenting device is just a matter of choise.
My name is John Marrinan, and I'm your resistent expert on Oscilloscopes for the next few weeks. As an Field Application Engineer I see a huge range of uses for scopes in the modern world of technologoy and physics. If there are any questions you'd like to ask or comments on my posting I'd love to hear from you.
The other day, I received a request for information on digital scope fundamentals. A very nice gentleman, Ed, had just purchased his first digital oscilloscope and was looking for help in learning its basic operation. You see, Ed is an old-time Tektronix user. He lamented that he had two Tektronix scopes “that I like, but both are ancient. But, as you know, they go on forever…” He had an application that required him to capture his waveforms for analysis. That simple need had forced him to finally upgrade to a basic digital oscilloscope.
Admittedly, when I came out of college, digital scopes were pretty common. I'm old enough to say we did have analog scopes in our Uni, but I know there a lot of people out there that actually never used an analog scope. What strikes me, though, is since the introduction of the digital scope, the pace of innovation in oscilloscopes has been staggering. Just the other week, we (Tektronix) introduced our new TBS1000B oscilloscope platform. For $550, you get a basic 2-channel, 50-MHz oscilloscope with zoom, 34 automated measurements, datalogging, limit testing, and a host of other goodies. Just a few years ago, the basic scope we introduced had the same quality acquisition system but less than half the automated measurements and none of the features like datalogging and limit testing. The move to a digital-based platform has enabled our engineering team to continuously add features to make our scopes easier to use.
But enough about us. I’d like to hear about your favorite scope features and experiences with the changing world of oscilloscopes.