new cheap DSO vs. good old Tek scope - Page 1
Forum section: electronics / beginners

author: tom.holzwurm
author_rank: Newbie
timestamp: June 23, 2018, 09:14:35 am
content: Dear colleagues,I'm not a newbie in electronics nevertheless new in this forum. I've studied a lot of reviews about the new cheap oscilloscopes ( DSO not MSO ) and I was surprised about lots of new features realized in these devices.In former times I was forced to develop microprocessor cicuits and RF-circuits, where bandwidths of 200MHz were needed. In the meantime I'm working with IoT Stuff, where some nice analytical functions as RS232 decoding or I2C would come in handy.Currently I own a Tek 754D which is in great shape, but I don't need 500MHz anymore. So my question is, would it make sense to switch to e.g Siglent SDS1104X-E or Siglent SDS1204X-E or similar.OK, 50Ohm input and external triggers are missing and you don't have delayed sweep, but you can control the scope by browser, you have standard USB interfaces and not GPIB and much more.Whats your experience and advice .....Thanks in advanceRegardsThomas

author: Gyro
author_rank: Super Contributor
timestamp: June 23, 2018, 10:07:49 am
content: If you've got a 754D in "great shape" I'd hang on to it whatever else you do. Selling it wouldn't yield as much as it's worth.If you just want RS232, I2C etc decode, then I'd just pick up a cheap 8 bit logic analyser off ebay and use it with Sigrok. It would give you all the decode features that you are missing at virtually no cost. Probably with better decode capability then a scope will offer you. For the ~Eur10 it would cost you, it's worth just buying one and seeing if it is sufficient for your needs.

author: tggzzz
author_rank: Super Contributor
timestamp: June 23, 2018, 11:03:19 am
content: Quote from: Gyro on June 23, 2018, 10:07:49 amMost definitely.Use the scope to ensure signal integrity in the analogue domain. Once that is good, switch to the digital domain and use digital tools, e.g. logic analysers and printf statements. More expensive LAs have better triggering and filtering capabilities, allowing you to concentrate on the points of interest.The killer use-case for storage scopes is capturing single analogue domain events, e.g. PSU sequencing and transients.

author: rstofer
author_rank: Super Contributor
timestamp: June 23, 2018, 02:23:40 pm
content: There is no substitute for bandwidth, except channels.I'm not getting rid of my Tek 485 any time soon even though I bought the DS1054Z and it is now my primary scope. If I want to see a leading edge (fast rise time), I'll have a better chance with a 350 MHz scope than a 100 MHz scope.But I bought the DS1054Z for the decoding options. I play around with uCs and FPGAs and while bandwidth is still an issue, decoding is very handy, especially for I2C and SPI.I would absolutely keep the 500 MHz scope for bandwidth but I would use the DSO for channels and decoding plus lower frequency projects.

author: Haatveit
author_rank: Regular Contributor
timestamp: June 23, 2018, 05:21:16 pm
content: Older scopes like your 745D are amazing scopes within their own arena, if that makes sense. You will pay dearly to get the same type of analog bandwidth on a modern scope... I would hang on to that older Tek for dear life. In fact I was hoping to buy one used myself (I don't have one) but they are quite expensive.I would buy a cheap / slow scope for decoding, like a Rigol or perhaps Siglent scope. As long as they're fast enough to do the serial stuff you need. Or, you could just get a straight USB logic analyzer.You lose out on the time correlation of an expensive modern scope, but then as you said that's not really within your budget. And often you can achieve similar results by clever triggering shared between the logic analyzer and your scope.