In the datasheet of ADF4110 is described, that a prescaler is included besides a 13 Bit B-counter. The values given of the prescaler are 8/9, 16/17, 32/33 and 64/65. Does it means that the prescaler divides the RF-In frequency in fractional way, e.g. RF-In = 180MHz -> Output of the prescaler by selecting 8/9 = 159.99998Mhz? What are the meanings of the units B, BP and A in the description of the prescaler on page 12 of the datasheet?