From cheater00 .
Sent Sat, May 11th 2013, 23:30
YW. The thing with digital scopes is that unless you get one with "digital phosphor" or "virtual phosphor", the display is going to be really shitty, and you don't want a scope like that. Digital scopes that have that cost a lot in general, rigol being the cheapest of the pack. Seriously get an analog scope and don't worry about displaying CVs, you can do that with your computer. A cheap analog scope is going to be way cooler for creativity than a digital one, even a fairly expensive one. Cheers, D. On Sat, May 11, 2013 at 11:09 PM, bagofskin <firstname.lastname@example.org> wrote: > Awesome advise. Thanks man! > > Scott > > On 2013-05-11, at 2:53 PM, "cheater00 ." <email@example.com> wrote: > >> The "vector rescanning" technique is not possible on DSOs because they >> alias waveforms. DSOs also suck for stuff like Lissajous patterns and >> in general x-y display. But unless you get a bistable analog storage >> oscilloscope like one of the Tektronix 7000 series bistable storage >> scopes that start at around $400 used you have to use a digital scope >> to see slow signals like CVs. Those are, however, well suited for >> analysis via line-in - just get an analogue volt meter with recorder >> output, select the right range, and take the output into your sound >> card. >> >> When buying any scope, make sure it can do XY mode, that it's at least >> dual trace, that it can subtract signals (A-B), and that it has >> 1Megohm inputs, not 50 Ohm ones. >> >> Try to go for scopes where the CRT uses at least 20 kV acceleration voltage. >> >> When buying a scope from ebay, ask the seller if it has any burn-out >> (don't buy one where there's something burnt into the phosphorus, like >> on an old TV). Ask the seller to use the scope's callibrator (most >> scopes have one, if not ask him to use an external one). The >> callibrator is a square wave generator. Ask the seller to take a >> picture of the scope displaying an image of the calibration signal on >> each channel at once, such that the waveforms cover 80% of the >> screen's height. Make sure the square waves aren't lopsided or curvy, >> that there's no ripple, and that the traces aren't thick (a sign of >> noise). >> >> When buying in person, make sure to plug it in and see if it works, >> use the procedure above. >> >> Always ask if probes are included. It's a hassle to get extra probes. >> >> Once you get it, let it run for a couple days without shutting it off. >> Make the trace very dim (just barely visible) so that it doesn't burn >> anything in to the phosphorus, or even turn it down completely. See if >> it still works afterwards. Don't give out any ratings until you've >> done that. >> >> Learn what triggering is and check if it works. It's useful. A scope >> with external trigger is useful for displaying synth waveforms and how >> they react to filters etc, but only if you have a modular with a >> counter. >> >> Cheers, >> D. >> >> On Thu, May 9, 2013 at 1:54 PM, Thomas Strathmann <firstname.lastname@example.org> wrote: >>> On 08.05.13 21:31, Nicole Feeder wrote: >>>> I bought an oscilloscope a few years ago. I looked around a lot for a >>>> used one, but it was tricky for me to find something at the time. I >>>> ended up settling on a small, new digital scope - Rigol DS1052E 50MHz. >>>> I've been happy with it. It isn't quite as nice as some of the >>>> Tektronix's scopes I have used, nor as sensitive and whatnot as some >>>> analog scopes, but I was spoiled in the physics department for years. >>>> For under $400 it is a nice, reasonably sized scope that fits on my >>>> bench well and has good functionality. >>> >>> Seconded. I've got the 100MHz version which is basically the same >>> machine. Compared to other (often fancier) digital scopes in the same >>> price segment I'd say that the Rigol definitely feels sturdier and not >>> as wobbly in day to day use. Although it should be noted that there are >>> probably some DSOs that are quieter in operation. The fan in the Rigol >>> is not the best possible one (a small, high-speed, low-cost thing). All >>> in all I don't regret buying it and wouldn't go back to analog for most >>> measuring tasks I do. >>> >>> Thomas