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How to get rid of frequency images above 170 MHz with DAC39J84 EVM?

OysterMussel
Prodigy 20 points
Other Parts Discussed in Thread: DAC39J84

I am getting an approximately 200 MHz image next to the 170 MHz frequency that I am putting out of the DAC39J84 EVM. I am using HSDC Pro to control the DAC via the TSW14J10 EVM. I have attached a screenshot of the settings in HSDC Pro and also screenshots from the spectrum generator that is attached to the output. Please tell me what settings I should have for my DAC in order to make the image frequency go away.

my DAC39J84 Image Frequencies.pptx

  • 0
    TI__Mastermind 44680 points

    Hi OysterMussel

    We're reviewing your question. Someone will respond as soon as possible.

    Regards,

    Jim B

  • 0
    TI__Guru* 78444 points
    OysterMussell,

    Please refer to figure 40, first stage FIR interpolation filter for the first stage frequency response. The data rate is only 368.64MSPS. With 170MHz IF input, you will get a 200MHz image that is not fully rejected by the interpolation filter. You will need to keep your signal bandwidth within the data rate.

    You may:
    1. increase the input data rate
    2. use lower input frequency + complex mixer to get to 170MHz
    -Kang