R&S CMU200 as generic T&M equipment

[Ice-Tea]

Hehehe... feel free to shoot me a PM of you are interested in any way

[Ice-Tea]

Dusting of a CRTU-RU. Pretty much like a CMU200, except for the 50W input (which is rare on CMUs) and the power coupler. Anyone suggestions for a good test for the power coupler (preferably using the unit itself)...

OK figured it out. Used a CMU as second RF source. No settings, nothing. Learned some more RF stuff today

[usagi]

So a CMU has a swept SA? I thought it was like most of the GSM etc. anaylizers, and had a fixed, FFT based spectrum analyzer. Damn, if I had known I would have bid more on one a few months ago.

it can be had cheaply on ebay because it has SA functionality but isn't sold as one. it's amazing value for the $.

[corn11]

So a CMU has a swept SA? I thought it was like most of the GSM etc. anaylizers, and had a fixed, FFT based spectrum analyzer. Damn, if I had known I would have bid more on one a few months ago.

It has a (VSA)/FFT based topology. I've attached a cutout of the block diagram from the CMU service manual.

*corrected s. below

[tmbinc]

It is a swept SA, at least for the spectrum analyzer mode. The RBW is implemented digitally on the DSP (and on their DDC ASIC). If you look at the files of the OPSW, you can find the DSP programs associated with the various RBW settings.

It does _not_ have an FFT SA mode. But it can do other DSP-based measurements like Power, Freuqency, Power-over-time etc.; and then for the communication analyzer functions the baseband processing happens on the dedicated link units.

[Bicurico]

Tracking Generator implementation:

https://youtu.be/qoHIg93_G9E

Regards,
Vitor

[Ice-Tea]

As an FYI: the ones with the audio option are now gone, at least the ones from units with little or no issues. Perhaps some of my "problem children" will turn out to have it once they are nursed back to health but right now no more audio units 

[corn11]

It is a swept SA, at least for the spectrum analyzer mode. The RBW is implemented digitally on the DSP (and on their DDC ASIC). If you look at the files of the OPSW, you can find the DSP programs associated with the various RBW settings.

It does _not_ have an FFT SA mode. But it can do other DSP-based measurements like Power, Freuqency, Power-over-time etc.; and then for the communication analyzer functions the baseband processing happens on the dedicated link units.

Ok thanks for the correction my assumption was mainly based on the architecture which is of course identical if you use just some digital filters for the RBW but I asumed they would have gone the other way

[Ice-Tea]

One CRTU-RU gone. One remaining.

[Ice-Tea]

Second CRTU-RU gone.