DHO924 - 250MHz scope at 312.5 MSa/s (wtf?) - Page 1
Forum section: electronics / testgear

author: czbaterka
author_rank: Contributor
timestamp: February 18, 2025, 09:15:11 pm
content: I was checking out Rigol DHO924 specs and I don't understand one thing, how can they advertise the scope as 250MHz capable scope if it does only 312.5 MSa/s per channel in 4 channel operation?That will probably cause some noticable aliasing right?

author: xtech
author_rank: Regular Contributor
timestamp: February 18, 2025, 09:22:23 pm
content: You are right, it is barely usable even in 2 channels mode (625Msps). Just a marketing. It makes sense only to buy 70/100MHz scope from that family and also don't expect too much. Thats why that scopes cost less that old Tek TDS30xx.

author: TheoB
author_rank: Regular Contributor
timestamp: February 18, 2025, 09:28:33 pm
content: Yes. The maximum bandwidth is only available for single channel mode. It would be more correct if the frontend bandwidth would be made a function of the sample rate. Aliasing will also happen in single channel mode at 100ms/div. I guess they don't do that as you can still follow the envelope of the signal, even if aliases occur.

author: 2N3055
author_rank: Super Contributor
timestamp: February 18, 2025, 09:45:43 pm
content: This is something I have been saying for more than 2 years.. Rigol fans keep attacking me.Siglent SDS8000xHD does not violate Nyquist.

author: ataradov
author_rank: Super Contributor
timestamp: February 18, 2025, 11:05:46 pm
content: Nyquist is about bandwidth, not maximum frequency. If you can be sure that there is no low frequency content in your signal, you can accurately sample it. Obviously this requires specific setup, but that's just life. I'll take higher everything any day of the week, even if it is not possible to use everything all at once. You just need to keep in mind the limitations of your measurement setup. But you have to do that anyway.

author: 2N3055
author_rank: Super Contributor
timestamp: February 18, 2025, 11:33:14 pm
content: Quote from: ataradov on February 18, 2025, 11:05:46 pmIf we are talking about software defined radio you are right.If we are talking about realtime digital oscilloscope you need to sample always above Nyquist to be able to reconstruct full shape of input waveform in time domain...

author: ataradov
author_rank: Super Contributor
timestamp: February 18, 2025, 11:55:53 pm
content: If you are observing bandwidth-limited signal on some high frequency carrier, you can undersample it and you will have reconstruction of the envelope with a lower carrier. This is not going to be the most common use case, but it is a use case and I'd rather have this capability than not.If it really becomes an issue, it is always possible to filter the signal externally. It is not possible to increase the sampling rate.In any case, they are not lying. They presented the specs. If you don't like the specs or they make no sense for your use case, find something else that works.

author: Fungus
author_rank: Super Contributor
timestamp: February 19, 2025, 12:36:47 am
content: Quote from: czbaterka on February 18, 2025, 09:15:11 pmYes, but it's easy to turn on the bandwidth limiter if you're using all four channels. Drop it down to "only" 125Mhz and you're good.The 924 isn't well specced or priced. I wouldn't recommend one to anybody.

author: Fungus
author_rank: Super Contributor
timestamp: February 19, 2025, 12:38:53 am
content: Quote from: 2N3055 on February 18, 2025, 09:45:43 pmYeah, but it can't do 300MHz on two channels when you need it.(measured bandwidth of the 924 is around 300MHz)

author: hussamaldean
author_rank: Unknown
timestamp: February 19, 2025, 06:29:16 pm
content: Thats why I went with Rigol MSO5074 and will unlock it to full bandwidth.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 19, 2025, 06:58:13 pm
content: Quote from: hussamaldean on February 19, 2025, 06:29:16 pm"Unlock" sounds innocent, whereas I believe you actually mean to crack the product and abuse the licensed bandwidth limit.If you actually compare approximately like-to-like, then the 200 MHz instrument in the MSO5000 series that you mention is significantly more expensive than the '924, so it's not a very practical alternative for those looking to spend in the '924 ballpark and respect the license conditions, since it pays for a living for engineers who develop those products.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 19, 2025, 07:22:54 pm
content: buy the 924 and know 1st hand it's limitation, me not buy ones with say at least 4 times sampling of the bw

author: hussamaldean
author_rank: Unknown
timestamp: February 20, 2025, 04:21:23 am
content: Quote from: shabaz on February 19, 2025, 06:58:13 pmA friend of mine who lives in Canada ordered DHO804 and asked about the hacking, they says it is ok to hack no issue. (From reseller of rigol in Canada).I call this a great way to promote your products.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 20, 2025, 05:08:28 am
content: Sure.. name the reseller? I'll go ask Rigol what they think of it.It's not ethical, in a thread where someone is contemplating legitimately purchasing an instrument, for you to encourage them to buy a lower-bandwidth product and hack it. If everyone did as you did, it would push the price of instruments up.

author: H.O
author_rank: Frequent Contributor
timestamp: February 20, 2025, 05:50:06 am
content: Pretty much every hobbyist does what he did. It's what's keeping the sales up on these types of scopes.Sure, you can argue the ethecality of it but I'm pretty sure Rigol wouldn't have sold NEARLY as many scopes over the years if it wasn't for the "get more than you're paying for" opportunity. Selling a lot of scopes also puts food on the table.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 20, 2025, 06:11:51 am
content: Quote from: H.O on February 20, 2025, 05:50:06 amOh, are you condoning this?Please don't tar every hobbyist in this way. You do what you want. I don't care. It's unethical, and is completely disruptive in a thread where a user was legitimately considering purchasing a particular bandwidth 'scope. If you want to run hacked instruments or software, that says more about you than anything else.If you want to screw over engineers who develop these products and need to earn a living, that's your choice.

author: ataradov
author_rank: Super Contributor
timestamp: February 20, 2025, 06:37:58 am
content: What is going on this thread? Hacking Rigol scopes was always purposefully easy. That's what put them on a map in a first place. They made no attempt to stop it even though they had a ton of opportunities. They also made it even easier in the new model. People are buying their hardware like hot cakes.If engineers felt cheated, they could engineer an actually functioning protection system. It is not hard, you actually need to think though how to make the hacking so easy and remove a lot of Android's default protections. This will drop the sales of their scope a lot, of course.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 20, 2025, 06:56:57 am
content: That's missing the point. There's nothing wrong in relying on people's sense of honor when it comes to licensing; if anything, it's more customer-focused for their engineers to concentrate on the features that everyone wants, rather than concentrate on locking down for the idiots who will expend as much time as they are able to in order to crack firmware, even if the firmware was locked down in any more substantial way.It actually may beworseif those products have sold like hot cakes with fewer licenses enabled. What if some of the developers are paid on a royalty basis tied to the licenses sold for their features? That's quite normal business practise, especially if some of the software, for instance libraries of code, is farmed out to other firms. It's hurting your own peers.It's not in any way ethical to use what you have not legitimately paid for. It's the same argument that those who watch cracked cable/satellite TV devices use.If people don't want to call out bad behaviour that's their choice, but actually condoning it is not something everyone is prepared to do, I certainly won't.

author: ataradov
author_rank: Super Contributor
timestamp: February 20, 2025, 07:07:44 am
content: This is their marketing strategy. It is the same exact hardware as lower end models and they are not losing money on them. If feeling that people got something extra out of the deal makes them buy their hardware, I don't see why they would care. And people that don't want to hack anything can pay a bit extra.Plus for the older models they just unlocked all the options themselves out of the box. It probably cost more to deal with people trying to buy them.But whatever, be ethical. I'm sure Rigol people are thankful that people are not that ethical. They would still be an obscure company making white label stiff for others.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 20, 2025, 07:40:14 am
content: The people who will get screwed may be the ones in the weakest position to do anything about it. If Rigol is licensing parts of their software from other suppliers and tying it to licenses sold, then those very suppliers will not be thankful to you or Rigol. They are going to be the smaller firms. They might not be in a position where they can enforce Rigol to apply additional security measures to see a more honest volume of licenses purchased. That's merely one example of a possible repercussion that would directly harm your peers negatively.I could discuss that opinion that it may be a Rigol marketing strategy, but I don't currently see the point when that doesn't move the discussion, because individual engineers can still be screwed over were it a Rigol strategy or not.I'm not asking you to do the right thing. You're old enough to know what's right or wrong. But when someone is actually trying to encourage others to do the right thing, at least don't try to impede them. At the end of the day, if you were the engineer getting screwed over, I'd still be sticking up for you.

author: Fungus
author_rank: Super Contributor
timestamp: February 20, 2025, 07:46:17 am
content: ...

author: ptluis
author_rank: Frequent Contributor
timestamp: February 20, 2025, 10:59:55 am
content: Cracking, hacking, modding and so on is something that exists everywhere, cell phones, software, hardware, the automobile industry, etc. This is what makes sales of a certain model increase. Rightly or wrongly, companies end up realizing that if they limit their products too much, they end up having a stock full of outdated equipment that no one wants. When I was a software developer, we spent thousands of hours and euros developing anti-hack protections that were always hackable by some genius around the world. We concluded then it was more profitable to let them crack, mod, etc. and earn more in repairs and sales. I will give you a practical example: Microsoft, the most copied and cracked operating system in the world and the best-selling one too. However, Microsoft is aware of this and never worried about it. It reach to the Top thanks to computer piracy and cracks. From the perspective of a small creator at the beginning of his career, he rejects all this because he invests thousands of hours in development, and money in equipment, been there, see that and feel that too, but that's how life is, either we keep going on or we get left behind. In this era of AI, most will be left behind and the need for so many engineers will be reduced in many areas. In programming using AI, it is very easy to create software in a few minutes, instead of taking months. I recently tested the creation of an application in Python in an AI to obtain the percentage of a battery according to the maximum and minimum value and present the result in a table, the AI ​​did and corrected the errors in 2.25 minutes, if I were to write the code it would take longer. What I mean by this is that in the era we live in today, those who limit their products too much do not survive and in the case of this topic Rigol DHO804 sales increase daily not because it is a wonderful piece of equipment but because it can be hacked. People like it and will probably buy another model later from the same brand. The same with Siglents, etc. Then they stay loyal to that brand.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 21, 2025, 12:31:56 am
content: Quote from: ptluis on February 20, 2025, 10:59:55 amIf you want a home full of cracked/hacked gear, that's on you.All software and licenses are not free just because you or someone else managed to hack it.You agreed to abide by the license terms, and then deciding to unilaterally go back on it is dishonest and unethical, and I've already given an example of how it negatively affects the smaller firms and individuals - actual engineers - so you're not setting a good example as an engineer either.The excuse that it must be benefitting the manufacturer and that, therefore, that makes it OK is weak. Show me a statement from the manufacturer that they are OK with you abusing their license terms. Because there are certainly statements to the opposite on their websites.Now, if, despite all that, you're still fine with it, you do what you want to do. Enjoy your pile of cracked equipment.But if you're going to actively encourage others to do this on a thread that had nothing to do with hacking, then you should certainly expect others to call you out on it - and if you had any moral fiber, you'd certainly not try to stop someone pointing it out.If you wish to wallow in the scum rather than being a plain simple member of society who doesn't freeload, then that's up to you. But don't assume everyone will do the same as you.

author: ptluis
author_rank: Frequent Contributor
timestamp: February 21, 2025, 10:59:14 am
content: Quote from: shabaz on February 21, 2025, 12:31:56 amI'm dealing with an woke troll super hero right? You have an interpretation problem right? If you have the knowledge enough about businesses you certainly know that any business must have everything licensed and that any inspection checks for hacked equipment, software and everything inside the business, or you think it's all an anarchy? If you do, you are living in a different dimension! But I get it, you wake up one day and decided to be a woke super hero and fight the world! Good luck with that!BTW Instead of insulting everybody Why don't you create a super perfect anti-tampering system and insert a C4 explosive charge inside to punish all those who hack devices?When you do, tell me and I'll open another business, selling coffinsthe world is definitely gonna blow because we are all hackers and nasty people.If Rigol, Siglent, and all the others won't take any actions against their own products being hacked why in the hell are you full of rage? They keep releasing new equipments without any kind of new anti tampering system because people buy them. Those two brands are the most well known in the world and probably the one's that sell more.And finally regarding Microsoft, as soon as they realized that their loosing marketing share with their 11, 12 windows versions due to the anti-tampering, anti-install features, they decided to allow everybody to download new installation packages and install those versions on any computer or tablet, did you get it?That's the way things are, because I understand doesn't mean I agreeIf politicians won't give the proper example how do you expect the society to behave?What are you afraid of?

author: csuhi17
author_rank: Frequent Contributor
timestamp: February 21, 2025, 12:09:24 pm
content: What is the purpose of this topic and the message exchanges in it?The topic title is stupid, because 250 MHz does not mean 312.5MSa/s but 1.25GSa/s sampling rate.

author: Fungus
author_rank: Super Contributor
timestamp: February 21, 2025, 12:11:49 pm
content: On some Rigol models you can "upgrade" them by pressing the right sequence of buttons on the front panel (eg. DS1054Z).How can that be illegal?

author: ptluis
author_rank: Frequent Contributor
timestamp: February 21, 2025, 01:06:10 pm
content: Quote from: csuhi17 on February 21, 2025, 12:09:24 pmAsk shabaz

author: ptluis
author_rank: Frequent Contributor
timestamp: February 21, 2025, 01:13:11 pm
content: Quote from: Fungus on February 21, 2025, 12:11:49 pmAcording to shabaz you're an hacker!you can't do anything with what you paid and own, you can't even smash it without a proper authorization of the manufacturer.Concerning this scope it will be maybe another best seller due to alternative app that will for sure be released.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 21, 2025, 06:23:23 pm
content: Quote from: Fungus on February 21, 2025, 12:11:49 pmThis happened to be a thread that had nothing to do with hacking/cracking. Someone was looking to buy a device actually licensed for a certain bandwidth (i.e., they were not looking to crack a device), and then someone interjected with violating licenses with a lower-bandwidth device as an option.You chose to sit on the sidelines and then post some childish nonsense rather than support a fellow engineer who was trying to encourage people to pay for what they use, rather than screw their fellow engineers who develop all the nice features they want in instruments.You're not some young forgivably naive engineer going by your post count, you've had the time to think about this, so your misunderstanding here about illegality makes zero sense.If you violate an agreement, that's not, in and of itself, illegal. Instead, if anything, you've simply broken a contract.

author: J-R
author_rank: Super Contributor
timestamp: February 21, 2025, 08:05:36 pm
content: In hopefully the least offensive way possible, I will say that with some basic online research you can discover the fact that the CCP incentivizes Chinese companies to behave in specific ways, such as "skipping" certain cost-intensive product development steps and moving straight to manufacturing. So while we can debate the morality side, the Siglent & Rigol corporate culture is going to be such that they really don't care about this.

author: wata
author_rank: Newbie
timestamp: February 24, 2025, 02:56:55 am
content: Well, I don't think 312.5 MSa/s at 250 MHz is much of a stretch.If you switch to equivalent time sampling mode, you can make effective use of the 250 MHz bandwidth by limiting it to repetitive waveforms.https://www.tek.com/en/documents/application-note/real-time-versus-equivalent-time-samplingIn the early days of digital oscilloscopes, 100 MHz, 100 MSa/s oscilloscopes were mainstream (at least in Japan).Nowadays, it is said that the real-time sampling rate needs to be 10 times the bandwidth, and I think this is because the performance of AD converters has improved and prices have fallen.