Disclaimer: I bug T&M stuff, restore it and sell it. If I can, for a profit. I have a CMU200 for sale and I have two pallets more inbound (yes, 2 pallets). While my stakes in this are obvious, I tried to make the below as unbiased as possible. If you feel this is not the case feel free to propose changes.Some time ago, a member here was looking for a SG and I proposed the CMU I had for sale. While it is a unit conceived for testing cell phone communication of a previous generation, they often come with the optional SG. Same for the SA and power meter. As such, I consider it a good option for a general purpose unit. SG+SA+Power meter in a single package? What's not to like.
Obviously, and as can be expected, some folks agreed, some others didn't. So I set out to compile a short comparison. The premises: you need a SG+SA and you need to choose between budget chinese units or an ageing but premium R&S unit. Specs first:
Signal GeneratorThe CMU looses out on range. The 300MHz deficit in the upper range is perhaps defendable, too bad the lower limit is quite poor. Both are fairly evenly matched but the Rigol is a lot better as far as harmonic and non-harmonic is concerned.
Spectrum AnalyserRange wise, the same story. The CMU can accept a *lot* more input power, which may prevent you blowing up the unit if you do something stupid (or if you have a very strong transmitter to measure). The CMU will accept 200W peak power. If you try that on the Rigol, make sure to have a camera running
Then again, the Rigol runs circles around the R&S as far as noise floor is concerned.
Power MeterWell, it doesn't seem to be an option on the Rigol and I could not find a good candidate for a standalone unit. So, that's a win by default. Feel free to suggest a good sparing partner!
Then again, a tracking gen is not an option on the R&S so perhaps we should call this even too
Ease of useWell, only have the R&S so I can't comment on the Rigols. The R&S is made for 19" racks and is pretty bulky, the Rigols are most certainly smaller but there's also something to be said for not having three seperate units on your desk. In addition, the screen on the R&S is pretty good, a little bigger than the Rigol SA and a lot bigger than the SG. Even with the best of interfaces, I guess a 3-in-1 instrument will never be as easy to use as 3 dedicated instruments. Unfortunately, I wouldn't call the R&S interface as having 'the best of interfaces'. After some getting used to, I'd say it's fair but not much more than that. Keep in mind that the SA and SG are not the prime features of these things so "having an awesome interface for them" was probably very, very low on the priority list. Off course, I have some Rigol instruments as well and I wouldn't say they tick all the boxes either
The R&S has 2 in/out ports, 1 out port and 1 in port that can be flexibly configured, so it has that on the Rigols.
ConclusionWell, in as far as I should be making a conclusion given my stake in this, here's my 0.02$. For both the SA and SG, there's something to be said for both but with all other things equal I'd have to choose I'd pick the Rigols.
Then again, other things are *not* equal. I compared prices (without VAT, shipping and other cost) and I will probably be offering these CMU's for 1k€ or so (depending on options, perhaps, but for a unit with SG and SA) while you'd be out of 5k€ for a pair of Rigols. Which makes a CMU an interesting option, especially if you're just entering the game. You get a good unit and if you encounter its limits then at least you will
know why you will be spending a few €k more. And the R&S will probably hold its value a lot better than Rigols. Then again, if you already know the CMU won't be good enough you'll have to splash your money on something else.
Let me know what you think. And if you want one, shoot me a PM
Home
Help
Search
Login
Register
