| Products > Test Equipment |
| Does old test equipment really ever become truly obsolete? |
| << < (9/14) > >> |
| David Hess:
--- Quote from: pdenisowski on May 23, 2024, 06:59:22 am ---The quality of the FFT implementation is also really important - this has come a long way in the last 15 years or so. --- End quote --- The quality of the FFT implementation has come a long way; it has gotten significantly worse since the 1990s when an oscilloscope could display both the magnitude and phase results. This has actually held me back from buying a modern DSO; why would I buy something new that lacks this incredibly useful feature, especially when old obsolete DSOs had it? Without it, a modern DSO is no better for transient response analysis than an obsolete oscilloscope. And while we are at it, FFTs should also include a noise marker function, which depends on the RBW. Your FFT reports its RBW, right? RIGHT? The point of the above is that the FFT function is usually a check-off toy on most "modern" DSOs. |
| Fungus:
--- Quote from: pdenisowski on May 23, 2024, 08:20:31 am ---I once had a customer who was adding RF functionality to their product for the first time. One day I went in their lab and saw a really ancient spectrum analyzer on their bench. Someone (jokingly?) told me that it was to give them credibility: anyone touring their lab would see that boat anchor and say "Boy, these guys have been doing RF forever..." :-DD --- End quote --- Remember when Apple made a "lab" for their M1 launch and filled it with $100 FNIRSI tablet-scopes: |
| pdenisowski:
--- Quote from: David Hess on May 24, 2024, 01:31:48 am ---And while we are at it, FFTs should also include a noise marker function, which depends on the RBW. Your FFT reports its RBW, right? RIGHT? --- End quote --- Maybe I'm misunderstanding you, but our oscilloscopes report and allow you to explicitly set RBW when in FFT/spectrum mode. I can make and post a more detailed video showing this if you like, but here's a quick example https://youtu.be/acE3d4TpiW4?t=34 Noise markers are, in my experience, more of a spectrum analyzer feature than an oscilloscope feature. Noise markers also require correction for both RBW and the filter shape (which is not user-adjustable), so this is typically handled automatically by the instrument I mention this in a different video :) https://youtu.be/pL0pY-t8KWY?t=84 --- Quote from: David Hess on May 24, 2024, 01:31:48 am ---The point of the above is that the FFT function is usually a check-off toy on most "modern" DSOs. --- End quote --- Everyone has different needs or priorities when using an oscilloscope, but FFT / spectrum analysis is a critical feature for many of our customers. I could give a fairly long list of all the different ways it is used, but there have many been posts and discussions about this here on EEVblog. Again, my apologies if I'm misunderstanding you. One thing I've learned over many years working in the test equipment industry is that people often have very different ways of describing measurements, tests, etc. And of all the instruments I've worked with, oscilloscopes are definitely the ones where terminology varies the most among users and instruments :) |
| RolandK:
For me, main aspects are: - function: what can be measured, ranges, accuracy, some special features, eg. hw trigger possibilies of scopes. - interface: usablility, speed, easy access to main functions, - quality: low failure rate, construction, parts with plenty of headroom and fitting the purpose. - maintanance: service docs with schematics, service friendly buildup. Simpler circuits are easier to understand. - resource: energy consumption, occupied size. Then there are emotional aspects: - fun in use / repair - good TEA community (eg share tips, repair stories, free manuals) - Brand with good reputation for me, if an instrument gets obsolete, has to do with multiple aspects. And: A lot of instruments are mediocre even new. This are the ones which go obsolete very quick. Interesting examples: - heathkit, their function and quality is often sub-earth level. But maintanance and emotional aspects compensate for that. :-/O - fluke 289: superb function, a bit clumsy, bad interface, no service manuals - hp: they had designers who were responsible for good user interfaces and maintainability. :) With the advent of one knob menue driven interfaces some machines got nearly unusable. >:( - tektronix: analog scopes with good function, interface and maintenance. With the digital tds 744a or the like: superb function, but bad interface, like fluke 289 >:( - hp 4274a: full service manual, no customer parts, good user interface, but internal very complex, hard to maintain. - genrad 1689 compared to 4274a (very near to each other in function and age): better accuracy, worser user interface, simpler buildup, easier maintainance newer developments sometimes are not so good in these aspects, eg: - main functions hidden in 2nd or 3rd menue level - noisy because auf smps (which tends to fail early) - complex and overloaded banana software (ripes and rottens at the customer) - operating systems need minutes to boot, are slow and tend to security problems. - custom IC's, controllers with integrated flash not only protect the knowledge, but are unobtanium at all or short after maketing ends. - very quick out of service, no service manuals - developed by unexprienced new staff, who ignore existing knowledge (Danning Kruger effect), eg. hameg hm8142 is good, hm8143 has design flaws (do not connect both outputs antiparallel, one of them will be killed in a blink :wtf:), hm8142 has very good user interface only with the optional keyboard, which is removed at hm8143. ::) For commercial use, you may have a service contract with the manufacturer, that's it, the manufacturer drains your employers money. But afterwards these machines get very quick obsolete, as they can't be repaired anymore or it is too expensive or excessive "customer rights" or business quarter shareholder value driven managers push manufacturers out of buisiness with private persons (eg. keysight). Therefore, as private person, i like machines which fulfil many of the aspects mentioned above. Age is only indirect a concern, and has 2 aspects: - developent over time improves or worsens different aspects in newer machines. Norms (eg. electric safety) develop, too. - Lifetime: things get dirty (fixable) and wore out or fail (often fixable). Availability gets a concern if needed on the job. Jojo's are not good for 24/7 use. |
| 2N3055:
--- Quote from: David Hess on May 24, 2024, 01:31:48 am --- --- Quote from: pdenisowski on May 23, 2024, 06:59:22 am ---The quality of the FFT implementation is also really important - this has come a long way in the last 15 years or so. --- End quote --- The quality of the FFT implementation has come a long way; it has gotten significantly worse since the 1990s when an oscilloscope could display both the magnitude and phase results. This has actually held me back from buying a modern DSO; why would I buy something new that lacks this incredibly useful feature, especially when old obsolete DSOs had it? Without it, a modern DSO is no better for transient response analysis than an obsolete oscilloscope. And while we are at it, FFTs should also include a noise marker function, which depends on the RBW. Your FFT reports its RBW, right? RIGHT? The point of the above is that the FFT function is usually a check-off toy on most "modern" DSOs. --- End quote --- Keysight MSOX3000T I have can show both magnitude and phase, but it has only 64kPts for FFT so that is a limiting factor. So it is not like nobody has it. Other point is that it is obvious that users don't need it so much as you think. Otherwise it would be in every scope.... |
| Navigation |
| Message Index |
| Next page |
| Previous page |