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IF Frequency Of QPSK Modulator

We are implementing direct qpsk modulator in fpga. Our data rate is 60 Mbit per sec . In digital , we must make I=I(0)*Sin(2*pi*f*t) and Q=Q(0)*Cos(2*pi*f*t). (f is frequency)

Our question is that what is the value of f ? 

2. If we want to inteface fpga with AD9787  (DAC) for converting I , Q to analog , what is our sampling frequency ? 


  • Hi,

    The output frequency will depend on the I and Q data words that you will send to the DUT.

    Determine first the DAC clock rate you will need given a data rate of 60 MHz by referring to pages 35-36 of the datasheet. You may use the AD9787-EBZ plugin input configuration wizard in the ACE software as calculator even if you don't have an evaluation board connected to PC.

    Try generating data vectors using the DPG Lite software. The data vectors can be saved as text files which you may integrate in your system.

    This quick start guide is helpful too.