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OFDM power measurements

Hello everyone!

I'm working with a comercial RF module that works in 2,4GHz with OFDM and I need to measure the tx power to confirm to works good. I'm thinking to measure with an evaluation kit of ADL5904 (CN0399). Is it possible? If not, what IC you can recomend me?

Thanks!

- AJ -

  • Hi AJ,

    If you simply need to check the radio transmit performance on the benchtop for qualification purposes, then the CN0399 solution should work OK. Other choices exist that might be better, like for example LTC5596+Linduino kit. If you have access to a Spectrum Analyzer, that's a great solution and quite capable but costly. Be sure to use attenuator between transmitter output and detector / SpecAn input. 

    Be aware that sometimes OFDM signals transmit data in packets, so the Tx power becomes effectively pulsed, which means that you might need the detector to be capable of separating the pulses out to measure the rms power during a pulse.  

    -Bruce H. 

  • Hi Bruce_H, many thanks for your kindly support!

    Ok, I will study the option of LTC5596+Linduino kit.

    Yes, I use attenuators and I have one spectrum analyzer (R&S FS300), I made first measurements with the 0 Span mode. With this spectrum analyzer, for OFDM, I think this is the only way to measure the tx power. Is this technique suitable for this purpose?

    Thanks!

    - AJ -

  • Hi AJ,

    The FS300 supports up to 20MHz resolution BW, so as long as your signal fits in this BW, the zero-span will effectively display power vs time.  -Bruce H. 

  • Hi Bruce_H

    No, the FS300 supports up to 1Mhz resolution bandwidth, is the FS315 who supports up to 20MHz.

    I wil try it with the CN0399 and compare the results with the zero span option.

    Thanks!

    -AJ-