The bandwidth is not 500MHz

Hi, Everyone.

We used a spectrum analyser to measure the bandwidth of the EVB1000, and the software we use is

ex_04b_cont_frame. But instead of 500M I get 675M of bandwidth. Am I measuring something wrong?

Or the EVB1000 is not calibrated? Thank you for answering questions.

Hello,

I am not a RF specialist, but i can see PG delay settings (Pulse generator delay) or something. By this you can adjust BW i think. It is written in user manual, lets check it.

Jiri

Yes,But I want to make sure that my measurement is correct. Because Decaware should calibrate the EVB1000 actually.

Hi,

Our EVB1000 boards are calibrated for crystal offset, transmit power and antenna delay but not for channel bandwidth, so there will be some board-to-board variation on this. Channel bandwidth is not so critical for regulations as the standard 500 MHz nominal bandwidth fits easily within the emissions masks (for ETSI you just need to ensure your lower 10 dB bandwidth frequency isn’t lower than 6 GHz).

Your measurement of 675 MHz seems a bit large though. Some things to check:

  • Are you using RMS detector on the spectrum analyser? This is the detector that should be used. I see ‘Peak’ on the display - is this the setting used?

  • Your spectrum should look smoother. Are you using a good RF cable?

  • What is the PG_DELAY setting used in the example code your using?

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Hi,

Thank you for your reply.

In the first two points, I will ask about our measurement mechanism

The software we use is ex_04b_cont_frame, So the PG_DELAY is 0xC0.

Hi, S_Carroll_DW.
We use RMS detector on the spectrum analyser and the bandwidth as follows. It’s still over 650MHz.
Can you tell me what bandwidth you’ve measured? Thank you again.