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AFE7989: How to measure the IMD3 for 2 tones?

Andrew Su
Intellectual 930 points
Part Number: AFE7989

dears,

my customer is evaluating AFE7989, they are wondering the test method of the IMD3 for 2 tones:

would you please help to share the guidance?

thanks a lot!

  • 0
    TI__Guru 67904 points

    Hi Andrew,

    Please advise if the customer is asking on the TX, RX, or FB? Please advise if they are asking for Latte/CAFE commands, or if they need specific hardware detail

    On the TX, we would send out two tone waveforms (the waveform itself has two tones at +/-10MHz, sampling at 491.52MSPS) from the FPGA to the TX DAC output.

    On the RX, we would have two signal generators at +/-10MHz apart at the RF frequency, add the two tones through combiner, and send to the RX ADC input.

    This is a high level summary. Please let us know if we missed anything that you are expecting. Thank you

    -Kang

  • 0 in reply to Kang Hsia
    TI__Intellectual 930 points

    dear Kang,

    i will check with the customer.

    thanks!

  • 0 in reply to Andrew Su
    TI__Intellectual 930 points

    dear Kang,

    the customer need the guidance of how to send  Latte/CAFE commands when measuring the IMD3 for 2 tones.

    thanks a lot!

  • 0 in reply to Andrew Su
    TI__Intellectual 2170 points

    Hi Andrew,

    To send the waveform from the TX with two tones at +/- 10 MHz, you can use the following Latte commands:

    AFE.TOP.overrideTdd(0xf,0,0xf) # turn on all RX and TX
AFE.selectCh(2,0) # choose TXA
# AFE.selectCh(2,1) # choose TXB
# AFE.selectCh(2,2) # choose TXC
# AFE.selectCh(2,3) # choose TXD

## Send  tone
fin1=[-10,10]
amp1=[-13,-13]
fin2=[-10,10]
amp2=[-13,-13]

AFE.FPGA.sendMultiTone(0,fin1,amp1,fin2,amp2) # send multi tone at +/- 10 MHz

AFE.adcDacSync(1)

    Please advise the customer to uncomment the appropriate AFE.selectCh() line to measure on the desired channel.

    To visualize the RX input, please use HSDC Pro to capture the RX input and make measurements.

    Please let me know if there is any additional clarification needed!

    Thanks,

    Aman