Products > Test Equipment

Rohde & Schwarz CMU200

<< < (44/71) > >>

Alfons:
I am an absolute beginner when it comes to SA. The device is great for learning. It is the first time that I am dealing with a (functional) SA and due to the variety of functions you do not need any other devices to try it out. Only slowly am I beginning to understand how an SA works at all, and now do I know what a reasonable spectrum has to look like and how it is also possible to generate a plausible FFT with a DSO. Because with some settings you can get quite good FFTs on a DSO. But extremely incomprehensible compared to the CMU200. Nevertheless, I am amazed to see that my old Infiniium offers a few options-settings, that you would otherwise rarely find on an old DSO for generating spectra (center frequency, span, power and phase and the possibility of setting the sampling-rate independently of the timebase-settings and the memory depth to influence the signal display ...). I only understood that, after I dealt intensively with the CMU. Because of this learning effect alone, it was worth buying the CMU200.

Nevertheless, there are still a lot of questions for me. I'm trying to understand what the I / Q-measuring on the device do. I/Q vs. Slots to measure the Phase-data in a signal-package, which is available in the basic menu and therefore not only to be used for measuring certain GSM etc.. signals?. This is the only option that my device has, which is also available in the basic menu.

Another question is: what does an OCXO do compared to the built-in TCXO in General-Purpose Measuring ? A Chinese dealer offers option B12 for around € 30. Does it make sense to retrofit that? I don't think so, because the accuracy of the TCXO is quite high. But what is your opinion?

Ice-Tea:
The OXCO offers better timebase stability in the long run (will drift less over time) but it also drifts less with temperature variations in you lab etc. Unless you *know* you need it, I wouldn't bother. Accidently, another options is to use an external 10MHz reference. Which can be quite cheap as well.

Alfons:
Thank you, Ice-Tea, I think I'll leave it that way and run it with the TCXO. At the moment I really don't know what I need an OCXO for. Highest to upgrade the device to get a better sales price. But I think I'll keep it anyway.

Here are a few more pictures: RF1-Out to RF4-IN. It generates and shows even very small signals quite well. But I don't really know if the measurement is OK. I switched off Avarage once, but that doesn't change much.

Sas:
I don't have B17. I think it is a set of analog inputs and outputs of intermediate frequencies for external modulators and demodulators. There is also a set of IQ modulation inputs and outputs. I think that it is not very useful when working with analog modulations. Without the B17 module, only the 10.7MHz IF output of the receiver. This is the IF3 output after analog RX conversion and the analog input of the DSP module for digital analysis. Sound demodulation with analog modulation should not be a problem.
The TCXO oscillator is sufficient for a spectrum analyzer with RBW 10Hz. With the built-in OCXO, if you need to have a more accurate reading, you'll still use the external time base input for phase synchronization with other instruments.
In my first CMU200 there was already an OCXO generator at the time of purchase. I bought ocxo for the second CMU200 because of the pretty good tx generator with AM, FM, FM Stereo modulations. I also use the generator as a LO or RF signal mixer for the tracking generator. I use CMU200 as a working tool in an electronics workshop, it is not super accurate but universal, convenient interface and everything at hand. I do not regret buying OCXO. The original OCXO R&S module B12 for € 30 is a very good price. If you plan to sell it is probably an unnecessary investment.

Alfons:
OK, I can try it out. But it has become a little more expensive? Well, 35 € is still OK. This one here: https://de.aliexpress.com/item/4000433902250.html?spm=a2g0s.9042311.0.0.672a4c4dukbieC

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod