From bagofskin Sent Sat, May 11th 2013, 21:09
From bagofskin Sent Sat, May 11th 2013, 21:09
Awesome advise. Thanks man! Scott On 2013-05-11, at 2:53 PM, "cheater00 ." <xxxxxxxxx@xxxxx.xxx> 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. >=20 > 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. >=20 > Try to go for scopes where the CRT uses at least 20 kV acceleration voltag= e. >=20 > 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). >=20 > When buying in person, make sure to plug it in and see if it works, > use the procedure above. >=20 > Always ask if probes are included. It's a hassle to get extra probes. >=20 > 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. >=20 > 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. >=20 > Cheers, > D. >=20 > On Thu, May 9, 2013 at 1:54 PM, Thomas Strathmann <xxxxxx@xxxx.xxx> 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. >>=20 >> 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. >>=20 >> Thomas