Hello,
I want to generate a FMCW Ramp from 24.0 to 24.25 GHz. I want to trigger the Ramp steps with the TX_DATA pin from a STM uC. The Step word is set to 8192 and the Dev-word to 5120. My Ref_IN is ac coupled with a 100MHz oscillator. For normal countinius Ramp generation there are no problems. But with the TX-DATa as ramp clock trigger I need more than twice the number of trigger pulses as set in register 15 (see Figure 2).
For example, if I use the TX_data as trigger for each ramp and the intern clock for the Steps, than I can see that approx. every 10 ramps a trigger puls is not recognized and the ramp starts with the next but one pulse (see figure 1). But that not explains why I need twice of the pulses (more than 16384) by triggering each step of ramp.
FIgure 1
Figure 2
Yellow line are Tx_DATA pulses, green line: V_tune voltage
Here are my Register settings:
//Initialisation ADF5902
0x02000007, //Register 7
0x0000002B, //Register 11
0x0000000B, //Register 11
0x0018000D, //Register 13
0x1D32A64A, //Register 10
0x2A20B929, //Register 9
0x40003E88, //Register 8
0x800FE520, //Register 0
0x01800827, //Register 7
0x00000006, //Register 6
0x01E38005, //Register 5
0x00001804, //Register 4
0x0189F883, //Register 3
0x00020642, //Register 2
0xFFF7FFE1, //Register 1
0x800FE720, //Register 0
0x800FE560, //Register 0
0x800FED60, //Register 0
0x800FE5A0,
0x800FF5A0,
//Ramp Defining
0x00000011, //Register 17
0x00000010, //Register 16
0x0004000F, //Register 15 STepSize 8192 slope0
0x0204000F, //Register 15 STepSize 8192 slope0
0x0404000F, //Register 15 STepSize 8192 slope0
0x0604000F, //Register 15 STepSize 8192 slope0
0xC002800E, //Register 14 slope0
0xC202800E, //Register 14 slope1
0xC402800E, //Register 14 slope2
0xC602800E, //Register 14 slope3
0x0018010D,//0x0018078D, //Register 13
0x0018012D,//0x001807AD, //Register 13
0x0018014D,//0x001807CD, //Register 13
0x0018016D,//0x001807ED, //Register 13
0x004F000C, //Register 12
0x2800B929, //Register 9
0x01002027, //Register 7
0x00000006, //Register 6
0x20F00005, //Register 5
0x00002004, //Register 4
0x0189F883, //Register 3
0x0000000B //Register 11
Does anyone have an idea what this might be due to.
Thanks a lot for every help
