Problem using R&S CMU300 Radio Communication Tester

[amirhosein]

Hi all

I'm a EMC technician in an academical lab and I want to test the functionality of a private land mobile. I am utilizing R&S CMU300 radio communication tester.
The problem is that when I turn on CMU, a message is shown at the start that says: "Please execute FM calibration from maintenance menu",
and when i go to maintenance menu and run FM calibration test, the "generator refused" message is shown.
I can not turn on RF generator either, and no connection to R&S support service can be possible for us due to unfair sanctions dictated to Iran.

Any help to solve this issue is highly appreciated.

Best Regards

 

[BradtheRad]

I am not familiar with your equipment, so these are merely ideas about possibilities.

* FM normally stands for FM modulation. Therefore does calibration require a carrier only, or does it need to be FM modulated?

* Do you have to choose certain settings? Switches? Dials? Gain? Frequency spectrum? Mode of reception? Etc.

* Can you tune to some FM broadcast, as a substitute?

* Can you attach an external FM generator as a substitute?

 

[amirhosein]

I am not familiar with your equipment, so these are merely ideas about possibilities.

* FM normally stands for FM modulation. Therefore does calibration require a carrier only, or does it need to be FM modulated?

* Do you have to choose certain settings? Switches? Dials? Gain? Frequency spectrum? Mode of reception? Etc.

* Can you tune to some FM broadcast, as a substitute?

* Can you attach an external FM generator as a substitute?

Thanks for your reply Brad,
About your questions, I should tell some tips respectively:

* Actually I don't know what CMU does in the FM calibration process. I think it should calibrate carrier frequency first. at the beginning of the test the "Generator refused" is message is shown.

* All the settings that I can change is carrier frequency, FM frequency and FM deviation. I should also determine the power level in dBm.
* I can not use any FM broadcast as a substituition, nor I can use an external FM generator.

FYI, I checked reference frequency of CMU and it works properly. I also used an external reference frequency to be assured about functionality of the PLL and it is working properly, too.