• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 46 subscribers
  • Views 277 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DAC39J84: 2x interpolation to obtain >0.5GHz analog bandwidth

Yilun Xu
Prodigy 80 points
Part Number: DAC39J84

Hi there,

I implemented the 2x interpolation on DAC39J84, which gives me a better looking spectrum and pushes the image frequency away.
In my case, with 2x interpolation, the DAC output sample rate (f_DAC) is 2 GHz. The input data rate (f_DATA) is 1 GHz. The LMFS is 8411.
With this configuration, can I generate the waveform of 0.5~1GHz using 2x interpolation? Am I correct that my analog bandwidth is limited to 0.5GHz due to the 1GHz f_DATA?
I looked at the DAC39J84 datasheet (SLASE48A). In 7.3.10 "FIR filters", "The transition band for all interpolation settings is from 0.4 to 0.6 x f_DATA (the input data rate to the device)". Since the f_DATA is still 1GHz in my case, does it mean that I cannot generate 0.5~1GHz waveform only using 2x interpolation? The NCO may help mix the frequency up, but I can only have 0.5GHz analog bandwidth? So I cannot take advantage of the 0~1GHz DAC output frequency even with 2GHz DAC sampling rate?

Thanks and best,

Yilun

  • 0
    TI__Guru* 91947 points

    Yilun,

    If you are to use complex data and interpolation, your maximum BW will be 0.8 x data rate. With a data rate of 1GHz, you max BW will be 800MHz. You have two options to increase this to 1GHz.

    Option #1. Use 1x interpolation and a sample rate of 1GHz.

    Option #2. Use 2x interpolation and a sample rate of 2.5GHz with complex data.

    See table 11 of the data sheet regarding this.

    Regards,

    Jim