May I ask the frequency waveform of the continuous triangular ramp generated by the ADF4159. Whose frequency is the frequency of the vertical axis of the waveform? Is it the FPFD, RFIN, RFOUT, REFIN or other frequencies mentioned in the manual? How to set this parameter? Can this frequency be set at will? Or should it be set to the size of the RFIN input frequency? I think it is the frequency of the input terminal of RFIN or the frequency of RFOUT mentioned in the manual. I do n’t know, right?

  • On top of what is mentioned in the datasheet, in the ramps and shift keying tab of the ADF4159 software GUI (free download from here) you can see the controls that change the ramp timings. The PFD frequency will change the actual period that the CLK1/CLK2 setting correspond to. ADIsimPLL (also free software available online) is useful to design and visualise the ramps you require. You can add in the CLK1/CLK2/DEV setting and it will simulate what the ramp will look like for the rest of your PLL design

    Please see here for a good informative video on simulating ramps with ADIsimPLL.