hello

I tested the Evaluation Board of AD9914 in the Frequency Jump mode and wanted to generate an output similar to the figure 40 of datasheet. Therefore, I applied a symmetrical square wave with the amplitude of 0/3.3v and with the period of 60usec to the DRCTL pin and specified the other parameters as follows:

Clock = 3GHz

Lower Limit = 400MHz

Upper Limit = 500MHz

Lower Frequency Jump = 445MHz

Upper Frequency Jump = 455MHz

Step Interval of the Positive Slope (P) = 1

Step Interval of the Negative Slope (N) = 1

Step Size of the Rising Ramp (STEP_{P}) = 51540

Step Size of the Falling Ramp (STEP_{N}) = 51540

With the above parameters I expected the frequency swept from 400MHz to 445MHz in 10usec and then jumped from 445MHz to 455 MHz immediately, in the following it swept from 455MHz to 500MHz in 10usec, then it stayed at 500MHz for 10usec and finally it swept down with the same sequence. But observation was that the range of Frequency Jump was not according to expectation and in the jumping up it happened from 445MHz to 475MHz and in the jumping down it happened from 455MHz to 425MHz. Also, in the case P=2 , N=2, in the jumping up it happened from 445MHz to 465MHz, and in the jumping down it happened from 455MHz to 435MHz. And only when P>=3 and N>=3, the range of Frequency Jump was according to expectation. Please explain the reason of this problem and give the solution to work with P<3 and N<3 correctly.