UMTS / 3G measurement  

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Smoogmox
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28/12/2012 6:31 pm  

In order to perform a measurement related to UMTS BTS, I believe the incident power density has to be calculated with reference to the DANL value of the device. What DANL value normalized to 1 Hz shall be considered for HF-60105v4 device at 2100 MHz? And what is the uncertainty of this figure at 2100 MHz? These two information bits are crucial for the calculation.
Do you have a procedure or an application note for properly calculating the incident power density of a UMTS source?
Thanks.


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Moderator
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29/12/2012 11:42 am  

Why should the DANL have any influence for a power measurement? This is nonsens.
Instead simply use the 5MHz RBW of the V4 units and you get a quite good idea of the power (3G hotkey).
For a "real" UMTS measurement you need a code selective measurement which will be possible with the new V5 SPECTRAN units.

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Smoogmox
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31/12/2012 2:39 pm  

I apologise, I meant NBW (noise bandwidth), not DANL.

According to the general guideline I have for measuring UMTS signals with a channel power enabled spectrum analyzer, which I believe is the case for v4, we need to select a small RBW (100KHz) and a VBW at least 3*RBW. Then we need to sum up the power readings of each trace bucket, multiply the result by the channel bandwidth and divide by NBW. An accurate power summation across all trace buckets pertaining to the channel should be accomplished with the provided mode in channel power control, I suppose.
NBW depends on the specific spectrum analyzer filter shape and is not the same of the -3dB filter bandwidth, generally speaking it is larger for analogue filters (using -3dB bandwidth would overestimate the calculation). So my question is: what is the NBW value for the 100KHz RBW setting in Spectran 60105v4? And what is the typical NBW uncertainty?

Regarding your hint to use a 5 MHz RBW, can you please elaborate what formula you suggest to apply in that case? Besides, there is no 5MHz RBW setting available, either 3MHz or Full (no information about what Full actually means for you).


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Moderator
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02/01/2013 5:59 pm  

All V4 units offer a 5MHz RBW, please have a look to the manual and the hotkey setups.
Anyway measuring 3G with a small RBW makes no sense at all.
The only way to do it right is with a code selctive measurement.

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Smoogmox
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11/01/2013 12:52 pm  

Unfortunately the setting values available on 60105v4 for the RBW are either 3MHz or Full: there is no 5MHz setting both on Spectran device menu and in MCS.
Can you please explain what you mean with "Full" setting for the filter?


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Moderator
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11/01/2013 3:20 pm  

If You have no 5MHz RBW you have no V4, please check your hardware.

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mm_dev
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11/01/2013 4:16 pm  

Note that the list of RBW entries isn't sorted by frequency, the 5 MHz setting is located near the end of the list.


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Smoogmox
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01/02/2013 11:58 pm  

Thanks, I found the 5 MHz RBW at the bottom of the list. But I cannot I set the 5MHz RBW on MCS, since there is no such entry there!
How can I use the 5 MHz RBW while using MCS?

Regarding my first question about NBW of Spectran, please note that setting a 100kHz RBW for measuring CDMA is widely used and in that case power is calculated according this formula:
http://mwrf.com/site-files/mwrf.com/fil ... power1.JPG
The above reported formula is taken from this article:
http://mwrf.com/test-amp-measurement/te ... m-analyzer
BTW, it is the same formula that is listed in the MCS channel power control, so I think it was devised by you for using a small RBW, according to what the Agilent application note cited above. Please confirm.


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03/02/2013 8:42 pm  

How can I use the 5 MHz RBW while using MCS?

Select the RBW in the MCS RBW selection field?
I am sorry. Your questions are quite weired...

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