Rigol MHO98 Teardown - Page 1
Forum section: electronics / testgear

author: PELL
author_rank: Regular Contributor
timestamp: September 21, 2025, 03:57:39 am
content: Haven't been here for a long time, I don't browse this forum much often now.Rigol just launch their new scope MHO98 and MHO900 series, thanks to my friend "依人如梦言如许", we now have an inside look of MHO98

author: PELL
author_rank: Regular Contributor
timestamp: September 21, 2025, 04:01:25 am
content: According to my firmware analysis, the main processing chip is a rebranding FPGA from Fudan Microelectronics, part number is FM230T. They make 1:1 Xilinx compatible FPGA

author: jackcheng
author_rank: Contributor
timestamp: September 21, 2025, 06:14:46 am
content: 大佬速度就是快

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: September 21, 2025, 10:13:34 am
content: At least no crusty trimmers in the frontend. Interesting though that the input stages of the four channels are not totally symmetrical. It looks like 1+3 are the same and 2+4 are the same, but e.g. 1+2 differ.

author: Martin72
author_rank: Super Contributor
timestamp: September 21, 2025, 11:01:57 am
content: The front-end chips, ADCs, and “CPU” are the same as in the DHO800....DHO4000(DHO800...DHO100 1 ADC, DHO4000 2 ADCs).The two relays per channel in the front end indicate a 50-ohm input, although I cannot find any corresponding resistors.But I hadn't found it in the DHO4000 teardown pictures either, too blind I guess.edit correction of ADCs.

author: voltsandjolts
author_rank: Unknown
timestamp: September 21, 2025, 11:27:59 am
content: Quote from: PELL on September 21, 2025, 04:01:25 amFudan were blacklisted by the US a few days ago, but AFAIK that only restricts export of American equipment to them, not imports of their products. Maybe Rigol branded it just in case.

author: TurboTom
author_rank: Super Contributor
timestamp: September 21, 2025, 12:36:23 pm
content: Quote from: Martin72 on September 21, 2025, 11:01:57 amSmall correction: There's one ADC in the DHO1000 and two in the DHO4000. So this hardware is probably very close in performance and configuration to the DHO4000 plus the additional digital interface. Seems Rigol also included a battery-backed RTC on this board. I'm quite curious how "well" this device performs sampling-rate-wise with the digital channels enabled...

author: Martin72
author_rank: Super Contributor
timestamp: September 21, 2025, 01:22:00 pm
content: Thanks, I´ve corrected it.I don't know how I got the idea that the 4000 has 4 ADCs, but a glance at the picture makes it clear that there are only two:https://www.flickr.com/photos/eevblog/52393925309/in/album-72177720302521598/But now help a blind man out, where did Rigol hide the 50 ohms?With Siglent and Co, they are quite easy to identify because they are quite large SMD resistors and then 2x 24R9 or 25 ohms.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: September 21, 2025, 02:28:57 pm
content: Maybe on the other side, but the resolution of that image is not high enough to be sure.

author: MadTux
author_rank: Frequent Contributor
timestamp: September 21, 2025, 07:26:14 pm
content: Quote from: PELL on September 21, 2025, 04:01:25 amSo it's Xilinx fallen out of a truck that went to laser engraver or true cold war style 1:1 silicone clone?Or spec sheet clone, new design that is binary compatible?

author: 2N3055
author_rank: Super Contributor
timestamp: September 21, 2025, 08:09:01 pm
content: Quote from: 0xdeadbeef on September 21, 2025, 02:28:57 pmI took a look at 4000 pics. There are no termination resistors on either side. It could be that front end chip is directly terminating input. That would be fun for overloads...P.S. Took another look.First relay chooses 50Ω or 1MΩ path.There seem to be 2 50Ω inputs on chip, actually 2 paths that are switched by 2nd relay together with corresponding PI attenuators.50Ω is DC coupled all the time. 1MΩ path goes to PhotoMOS and capacitor for AC/DC coupling. All range switchingfor 1MΩ is solid state in frontend chip.There are no external termination resistors. Front end chip is terminating.

author: Martin72
author_rank: Super Contributor
timestamp: September 21, 2025, 08:19:10 pm
content: Thank you, so I'm not blind after all, because I had searched through all the images I could find.QuoteOh yes, instead of replacing a resistor, it's the IC's turn—a disaster for the customer.One can only hope that Rigol has incorporated appropriate safety measures, because it is easier than one might think to “overdrive” the 50-ohm input.Do I believe that? No...

author: PELL
author_rank: Regular Contributor
timestamp: September 22, 2025, 04:00:05 am
content: Quote from: MadTux on September 21, 2025, 07:26:14 pmFrom a trusty source: Fudan actually got Xilinx's help when making these chip, Fudan now even has some RFSoC clone. And it's not made by TSMC!My personal guess is: At first, Fudan was trying to reverse engineering Xilinx FPGA then sell it to defense related company in China, but the result wasn't ideal. At the same time, Xilinx also wants to sell FPGA to these companies, but due to obvious reason they can't sell it directly.Then somehow Fudan convince Xilinx to help them build the clone chip, and now both Xilinx and Fudan make big buck of money out of this, it's basically a win-win deal from company standpoint.Note: I don't want to involve politics in this topic

author: jackcheng
author_rank: Contributor
timestamp: September 26, 2025, 02:35:17 pm
content: the ADC is same model with the one in DHO800, except it has 2 ADC. How is the 4GSa/s is calculated? Is it means 2G per ADC then multiple 2=4GSa/s? Does that prove that the DHO800 serials can "update" to 2GSa/s and 1G bandwidth? Is there anyone knows who has hacked the sample rate of DHO800 serials before?

author: eurofox
author_rank: Unknown
timestamp: September 26, 2025, 02:53:53 pm
content: Quote from: jackcheng on September 26, 2025, 02:35:17 pmYou should ask norbert.kiszka, he is currently hacking the DHO800/900

author: thm_w
author_rank: Super Contributor
timestamp: September 26, 2025, 09:25:17 pm
content: Quote from: jackcheng on September 26, 2025, 02:35:17 pmIts sequential sampling, yes 2G per ADC, then add the data together for 4.DHO800 will be limited by the front end bandwidth and the processing power of the CPU/FPGA. It has a different lower power part than DHO1000 and this MHO98 I assume. I'm not sure if we have any details on this "RT6888IF" IC.

author: Martin72
author_rank: Super Contributor
timestamp: September 26, 2025, 09:52:51 pm
content: The CPU is not included in this comparison, as the DHO800 has the same CPU as the DHO1000 and DHO4000 (Rockchip 6-core).FPGA could be another one, and as already mentioned, the front end might not even be capable of operating at up to 1 GHz.QuoteAnd you can pay for it.