I am doing some research about fmcw fast ramp on the ADF4159 EVA-board.
Photo 1 is the PLL setting, Photo 2 is the tuning waveform.
ramp mode: continuous triangular
fast ramp: enabled
the total frequency change of the up and down ramps are the same.
The differences are: up and down ramp steps
up and down time of ramp
frequency deviation per step
Question: how come I can't see the 16 steps down ramp? It is about half time of the up ramp, should be obvious.
By the way, when I pulse TXdata, I do see the change of frequency of 64 steps up ramp, 16 steps down ramp.
Waiting for the help! Thanks!
Big Update: In photo 3 I found the gap between up ramp. Blue is the Clk divider output, which shows each step.
I zoom in to the down ramp (photo4), I actually see the steps. Is that right?
However, the down ramp time is not what I program. How to explain it?