Oscilloscope - Which minimum BW and memory depth should I go for? - Page 1
Forum section: electronics / beginners

author: pcbraSil
author_rank: Newbie
timestamp: October 19, 2011, 01:40:39 pm
content: People say that 25MHz should do for analog.But what is the right gear for an advanced hobbyist to work with on the digital world?So, when choosing a digital oscilloscope for nowadays electronics, microcontrollers and whatnot, what is the minimum BW and memory depth requirements for an advanced hobbyist?Should I go for a MSO or DSO?Thanks in advance

author: sub
author_rank: Regular Contributor
timestamp: October 19, 2011, 02:02:08 pm
content: It depends on what you have in mind. If you don't care about anything faster than a PIC10F, then 25 would probably be passable, though your higher-frequency waveforms might start to become distorted---I wouldn't be hoping to measure risetimes. If you want to do higher-speed stuff (faster micros, FPGAs, etc.) then you would likely want 50MHz+.For digital work you want a larger memory depth (probably 1M+). I have neither a logic analyser nor MSO, so cannot comment on their relative merits.Probably the largest factor is budget, though.

author: saturation
author_rank: Super Contributor
timestamp: October 19, 2011, 08:28:42 pm
content: Quote from: pcbraSil on October 19, 2011, 01:40:39 pmI don't think there is a spec as a much as a bang for buck. I think the Rigol 1052e specs have a set a model for bandwidth and memory depth in the low price DSO category. Other scopes either meet or exceed it.In analog school work, RF requires one to examine the effects of transmission lines in terms of design, layout, wiring, shielding, antennas etc., so a scope that resolves RF is needed, but the higher the frequency response the more phenomena you can examine, the more you can afford and work with the more you become a black magic RF wizard.http://mysite.du.edu/~etuttle/electron/elect0.htmIn digital work, DSO commonly are used for the analog components of the work, such as the DAC output.Unless one knows the specific frequency a scope is being applied to, today a 25 MHz DSO is not that more costly that a 50 MHz. You can still save money and get models below 25 MHz, but if you compare bang for buck using the raw bandwidth and/or sampling rates for your money, you pay ~ more for scopes that are < 50 MHz. Actual costs vary by brand and added features in each bandwidth category, the question then is what are those features worth in the same bandwidth [ e.g. more memory means higher cost for the same scope with less memory.]For example, a DSO Nano is about $100 for 1 MHz. $400 gets you a 50MHz Rigol 1052e; you pay 4x more but get 50x more bandwidth.Unless you have a specific need, more memory in DSO allows you to zoom into details of a waveform at slower timebases, but the drawback is slow time bases and more memory taxes the CPU so the wfms/s drop; to not drop as much requires a faster CPU.I see the basic purpose of a DSO is to view waveforms best for each time base, so more memory is always welcome, but isn't strictly necessary.MSO or DSO? Unless the logic analyzer of the DSO is as good as one bought separately, it becomes a feature that balloon the cost of scope more than if both tools were bought separately. For eample, in the Rigol 1052D, its near $900 but it seems to me the screen is too small and cramped to see digital channels plus analog waveforms.

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 19, 2011, 11:46:47 pm
content: Quote from: pcbraSil on October 19, 2011, 01:40:39 pmthis relative term need more detailed explanation. and you havent mention your budget. since pretty much everything, the limitation of imagination is the... budget.assuming budget is not your problem, and assuming what an "advanced hobbiest" is in my mind, the spec should be anything larger than 50MHz MSO, ie with LA, or separate dedicated LA.