Hello,
I am using the evaluation kit for this board, which includes the Reference Pro, to produce an ramp that is at least >1 GHz wide, but am only trying to do accomplish a 200 MHz sweep for now. From what I understand, this board accomplishes this by sweeping a certain bandwidth (say 20 MHz) before calibrating the VCO to a new frequency, then sweeping another 20 MHz, and repeating this until the full sweep is accomplished. The GUI allows for a minimum time to calibrate the VCO between these smaller sweeps, with the goal of achieving a consistent time between ramp functions. I have attached a files with register mappings which reference my current software state when using TICS Pro.
R112 0x700000 R111 0x6F0000 R110 0x6E0000 R109 0x6D0000 R108 0x6C0000 R107 0x6B0000 R106 0x6A0003 R105 0x699C40 R104 0x68FFFF R103 0x673E00 R102 0x660000 R101 0x650000 R100 0x64C350 R99 0x63FD61 R98 0x62FFFD R97 0x618800 R96 0x600028 R95 0x5F0000 R94 0x5E0000 R93 0x5D0000 R92 0x5C0000 R91 0x5B0000 R90 0x5A0000 R89 0x590000 R88 0x580000 R87 0x570000 R86 0x560000 R85 0x55CE00 R84 0x540001 R83 0x530000 R82 0x527800 R81 0x510000 R80 0x500000 R79 0x4F0040 R78 0x4E00BF R77 0x4D0000 R76 0x4C000C R75 0x4B0800 R74 0x4A0000 R73 0x49003F R72 0x480001 R71 0x470081 R70 0x46C350 R69 0x450000 R68 0x4403E8 R67 0x430000 R66 0x4201F4 R65 0x410000 R64 0x401388 R63 0x3F0000 R62 0x3E0322 R61 0x3D00A8 R60 0x3C0000 R59 0x3B0001 R58 0x3A8001 R57 0x390020 R56 0x380000 R55 0x370000 R54 0x360000 R53 0x350000 R52 0x340820 R51 0x330080 R50 0x320000 R49 0x314180 R48 0x300300 R47 0x2F0300 R46 0x2E07FC R45 0x2DC0DF R44 0x2C3FA3 R43 0x2B0000 R42 0x2A0000 R41 0x290000 R40 0x280000 R39 0x27FFFF R38 0x26FFFF R37 0x250304 R36 0x240050 R35 0x230004 R34 0x220000 R33 0x211E21 R32 0x200393 R31 0x1F43EC R30 0x1E318C R29 0x1D318C R28 0x1C0488 R27 0x1B0002 R26 0x1A0DB0 R25 0x190C2B R24 0x18071A R23 0x17007C R22 0x160001 R21 0x150401 R20 0x14C848 R19 0x1327B7 R18 0x120064 R17 0x110110 R16 0x100080 R15 0x0F064F R14 0x0E1E30 R13 0x0D4000 R12 0x0C5001 R11 0x0B0028 R10 0x0A10D8 R9 0x091604 R8 0x082000 R7 0x0740B2 R6 0x06C802 R5 0x0500C8 R4 0x040A43 R3 0x030642 R2 0x020500 R1 0x010808 R0 0x00A49C
In the attached configuration, I have the min calibration time at 25 microseconds, which should be enough. What I observe is that when the sweep is low, (say < 100 MHz), the ramp duration is fairly consistent. However, for sweeps larger than this (say > 200 MHz), I consistently see that the ramp duration varies randomly within +- 5% of the ramp duration. I would expect that the ramp duration, even if it does vary, would do so at much smaller deviation than this. I have observed this behavior even with longer minimum calibration times (64 microseconds). Any ideas? Thanks in advance.
