Yet another "please help me choose my first oscilloscope" topic - Page 1
Forum section: electronics / testgear

author: Moriambar
author_rank: Unknown
timestamp: September 01, 2018, 08:08:00 am
content: Hi. Sorry for not being original.I recently have "pumped up" my bench with various appliances (hakko iron, a psu, BM235), but I still need to buy my first scope. I originally narrowed it down to SIGLENT SDS1104X-E and SDS1202X-E. The 1204X-E is kinda just out of my budget.I like a lot the built-in i2c and spi decoding capabilities, since I will need it a lot: most of my project make estensive use of i2c especially (I know about digital analyzers, the problem is that it is a pain for me to bring the computer on the bench, and when I do is usually to program/power an arduino or something like that).I don't have any "special needs" apart that and I just would like to have a good scope that will last and will suit most of my present and the "probable future needs".The thing is that I do not know how to choose between the two I listed above: there's clearly a difference in price due to the two extra channels in the 1104, but it is also 100MHz. Do you think that 2 extra channels are better than having a better bandwidth? Perhaps this cannot be answered for all the needs, but I think I am kinda a standard beginner.Also I don't know whether there are better scopes for the same price (I just know the siglent brand is good), and I tried browsing Rigol's website although the specs of their scopes are not as clearly listed as Siglent ones; so if you think I'm making a mistake and I should consider buying something else, please tell.If you read everything, well, I appreciate it a lot.If you can and want to help me… many, many thanks.Cheers

author: Fungus
author_rank: Super Contributor
timestamp: September 01, 2018, 08:11:03 am
content: Quote from: Moriambar on September 01, 2018, 08:08:00 amYes!(especially when you want to do SPI decoding...)

author: Moriambar
author_rank: Unknown
timestamp: September 01, 2018, 08:12:18 am
content: Quote from: Fungus on September 01, 2018, 08:11:03 amGreat reply. Unambiguous

author: Claudius2k
author_rank: Newbie
timestamp: February 12, 2020, 04:27:49 pm
content: That seems to be the common need beyond two channels (serial decoding).

author: jake111
author_rank: Regular Contributor
timestamp: February 12, 2020, 04:52:38 pm
content: If you are doing decoding or any sort of longer term measurement of the bus (i.e. not the very short capture ability of the scope) I highly recommend you look at a separate logic analyzer. There are many available, I have the cheap china style stuff like bus pirate and the like, as well as the Taiwan zeroplus, and some sigrok compatible hardware but nothing beats this saleae that I got. I can stream indefinitely thru USB and I never knew how much of a time saver this was until I had it. If you are a student they will give you a discount code for student purchase and it is well worth it IMO. I consider the decoding ability on the scope to only be useful for triggering and time correlated analog for the digital to troubleshoot bus electrical issues, however the saleae does analog in parallel with the digital and since I acquired this I've all but quit using scope for digital. In fact, for a while I rarely turned the scope on because of this since I was mostly playing with bus and protocol stuff... To reiterate, don't dismiss getting a separate good quality logic analyzer just because the scope has protocol decode. The typical low end scope's capture depth will be very limited and I've found this to significantly limit its usefulness.

author: twospoons
author_rank: Frequent Contributor
timestamp: February 12, 2020, 11:02:57 pm
content: When I bought a scope I went for bandwidth over channels. You can work around only having two channels, with creative use of the trigger input. You can't work around have insufficient bandwidth.I've also found little need for more than two channels, and as has been said above, a logic analyser is a better tool for bus decoding.

author: Fungus
author_rank: Super Contributor
timestamp: February 12, 2020, 11:45:20 pm
content: Quote from: twospoons on February 12, 2020, 11:02:57 pmWell, youcan... if you're a fan of constantly swapping cables back and forth.Quote from: twospoons on February 12, 2020, 11:02:57 pmTrue, but signals don't just vanish when they reach the number printed on the front of the 'scope, they just attenuate. Even a lowly Rigol DS1054Z willshowyour signals up to 350Mhz+, you just won't be able to rely on the on-screen measurements being accurate.Quote from: twospoons on February 12, 2020, 11:02:57 pmIt's a very personal thing. I use them all the time, and I'd never tell anybody who works with microcontrollers that 2 channels is all they'll ever need.

author: tautech
author_rank: Super Contributor
timestamp: February 13, 2020, 01:17:47 am
content: Quote from: Moriambar on September 01, 2018, 08:08:00 amWhich one did you get in the end ?

author: nctnico
author_rank: Super Contributor
timestamp: February 13, 2020, 06:44:53 am
content: Look at the GW INstek GDS1054-B. Can be hacked to 100MHz + protocol decode. 4 channels, solid firmware and not too expensive. If you work on designing your own circuits or digital stuff then definitely get a 4 channel scope.