Which Oscilloscope should I purchase for my requirements? - Page 1
Forum section: electronics / beginners

author: renegadeandy
author_rank: Newbie
timestamp: December 14, 2018, 01:14:38 am
content: Hi all!I am working on the OSSC project - it's an open source scan converter, it takes in "old analog signals" like RGB, VGA, Component, and Composite, and outputs HDMI.A lot of the original circuitry has been handled by the project's experts, however I want to understand at a more fundamental level what is going on within my setup. I.e I want to see the RGB signal coming in, understand it's form, and then trace how that gets digitized, before it is passed onto the Cyclone IV (FPGA) for processing.I don't particularly want to spend a huge amount of money, < $400 if possible. It needs to be optimised for 'video signals' if that is such a component of Oscilloscopes, and ideally offer me at least 2 channels, at 100mhz which appears to be fairly standard these days. There are likely other qualities I should be looking for given my setup and specific use case, and I would like to pull from your experience and preferences within the Oscilloscope domain to see what you use, and why!I really appreciate all patience, and guidance. (I have watched a lot of youtubes covering comparisons between oscilloscopes, and the importance of purchasing a 'proper analog oscilloscope' by our very own EEVBlog guru himself! But before I splash out, I want to see what this community would recommend, for a new comer , who has high aspirations within the electronics domain(I am coming from a highly experienced software background -- and have designed a couple of simple OSHPark boards which have worked etc, but want and need to take this next step to really understand what my signals are saying when they travel down my traces

author: FotatoPotato
author_rank: Regular Contributor
timestamp: December 14, 2018, 01:47:47 am
content: I would go for the Rigol DS1054z and mod it to unlock all of the options, which is super easy and quick to do. I have one and I love it and I think that would work best for you and it is right in your price range.https://www.amazon.com/Rigol-DS1054Z-Digital-Oscilloscopes-Bandwidth/dp/B012938E76/ref=sr_1_3?ie=UTF8&qid=1544752046&sr=8-3&keywords=rigol+ds1054z

author: tsman
author_rank: Frequent Contributor
timestamp: December 14, 2018, 01:52:06 am
content: A Rigol DS1054Z with theRiglol hackto enable 100MHz and all the options.A GW Instek GDS-1054B temporarily downgraded to 1.18 andlicense key generatorto enable 100MHz and all the options. It is only 1Gsps sampling in total and 250Msps if you enable all channels so 300MHz is going to be dubious...Other option is a Siglent SDS1104X-E. I think you can hack it for more options as well but you'll have to dig around in thebig threadfor how.

author: GigaJoe
author_rank: Frequent Contributor
timestamp: December 14, 2018, 02:38:42 am
content: i have 1054 and siglent 1202; I like siglent much better, but it has a bit more glitches (im tolerant to), and not sure about decoding

author: rhb
author_rank: Super Contributor
timestamp: December 14, 2018, 02:52:03 am
content: Take a look at the Siglent SDS1202X-E. It's currently $359 and purports to do video decoding. I have a Rigol DS1102E and Instek MSO2204EA. I also had an MSOX3104T briefly and an RTM3104. The sad fact is the SW quality even from the A list OEMs is not great.Siglent has a 30 day return policy and most reputable T&M sellers also offer that as well as offering to give you a hands on demo.Set up to do some tests in a few days and ask for demos.

author: Chriss
author_rank: Frequent Contributor
timestamp: December 14, 2018, 06:10:44 am
content: Hi!I would also prefer a Rigol or Siglent as they preferred above.I own also them and they are super good for the price and will make happy.Sent from my GT-I8260 using Tapatalk

author: renegadeandy
author_rank: Newbie
timestamp: December 14, 2018, 06:30:48 pm
content: Hi all,Thanks for your thoughts so far. Do you think settling on thehttps://www.tester.co.uk/siglent-sds1202x-e-bench-oscilloscope?gclid=Cj0KCQiAxs3gBRDGARIsAO4tqq1wLJiRZvC462onvaNrLn8jZ2fOoXys-3NnZA6rgvdEbzml7bIHmuYaAmbDEALw_wcBwould be a good ide?I am not sure what Oscilloscope based optimisations make sense for my video based workings.....does anybody have any experience around this?

author: tautech
author_rank: Super Contributor
timestamp: December 14, 2018, 06:37:33 pm
content: Quote from: renegadeandy on December 14, 2018, 06:30:48 pmGood choice and a best seller.You do need a DSO rather than a CRO for the nonrepeditive waveform work you propose.

author: rstofer
author_rank: Super Contributor
timestamp: December 14, 2018, 06:38:42 pm
content: Do you really want to watch the HDMI output on a scope? If so, HDMI runs at 165 MHz and the new standard is 325 MHz and there are NO inexpensive scopes that will accurately display these signals. I would think you would be looking at a 500 MHz or 1 GHz two-channel scope (because 4 channel will be insanely expensive).I like the DS1054Z and, for most purposes, the 100 MHz bandwidth is adequate. But that means I am looking at signals around 20 MHz or so. Square waves are hard to display because you need to include at least the 3rd and 5th harmonics and the 7th is pretty important as well. The DS1054Z will just about reproduce the 7th harmonic of a 20 MHz signal.Think what that means for a 325 MHz signal! Somewhere over 2 GHz of bandwidth required.Older VGA displays used to run about 50 MHz and you might get the general idea of the waveform on the DS1054Z but it won't be a faithful reconstruction.High bandwidth scopes are expensive. You can find used analog scopes with high bandwidth for a lot less money. I have a 350 MHz Tek 485 I bought for a couple of hundred bucks about 12 years ago - eBay.

author: rstofer
author_rank: Super Contributor
timestamp: December 14, 2018, 06:44:17 pm
content: Quote from: tautech on December 14, 2018, 06:37:33 pmIt looks like a great scope and I plan to buy the 4 channel version at some point. However, it still doesn't have anywhere near enough bandwidth to look at HDMI waveforms. It can't even do the 3rd harmonic of a 165 MHz square wave.I think I would post a question in the Test Equipment forum along the lines of "here is what I want to do, how much bandwidth would it take?". Make sure you mention HDMI and get the bandwidth nailed down first. THEN you can go looking for scopes that meet the required bandwidth. Or at least realize that what lower bandwidth scope displays has very little correlation in reality.

author: tautech
author_rank: Super Contributor
timestamp: December 14, 2018, 07:44:00 pm
content: Quote from: rstofer on December 14, 2018, 06:44:17 pmUnderstood.Maybe you missed this in the OP:QuoteA 200 MHz DSO shouldn't have too much problem with that.

author: rstofer
author_rank: Super Contributor
timestamp: December 14, 2018, 07:50:32 pm
content: Quote from: tautech on December 14, 2018, 07:44:00 pmYes, on the RGB side of the FPGA, that 200 MHz Siglent would be excellent. Well, close to excellent. The signals are probably around 50 MHz and we would only clearly see the 3rd harmonic and the 5th would be down somewhat. It might be entirely adequate. But hopeless on the HDMI side.I went to Keysight looking at high bandwidth scopes. They are pricey!We don't always realize how good we have it with these entry level DSOs. Decent bandwidth at very attractive prices. Maybe 1/10th of what they used to cost for similar bandwidth.

author: tautech
author_rank: Super Contributor
timestamp: December 14, 2018, 08:01:27 pm
content: Quote from: rstofer on December 14, 2018, 07:50:32 pmIndeed.In just the few years I've been selling, BW has doubled and functionality grown massively and all for the same price.....higher sensitivity, faster processing, good FFT, Decode, more memory, History etc etc.What will the next 10 yrs advancements bring ?

author: woodchips
author_rank: Frequent Contributor
timestamp: December 14, 2018, 08:33:08 pm
content: Do you have room for, and don't mind swapping around, for more than one scope?For high speed signals what about a Tek 7000 with a 7T11 and 7S11 giving 10+ GHz? Can then use a cooking DSO for the lower frequency stuff. HP do a similar sampling scope but be aware that it will only trigger to 1GHz. Yes yes I realise that these old bits of junk are no where near as flash as the scopes mentioned, but do you want to look at signals or not? Will a DSO ever have a 12GHz bandwidth, and trigger at that frequency, for less than the cost of a house?