SX1212频点设置求助

138****8538

从sx1212的datasheet(P14)看到如下内容
With an integer-N PLL architecture, the following criterion must be met to ensure correct operation:
.. The comparison frequency, Fcomp, of the Phase Frequency Detector (PFD) input must remain higher than six
times the PLL bandwidth (PLLBW) to guarantee loop stability and to reject harmonics of the comparison
frequency Fcomp. This is expressed in the inequality:
PLLBW ≤ Fcomp/6
.. However the PLLBW has to be sufficiently high to allow adequate PLL lock times
.. Because the divider ration R determines Fcomp, it should be set close to 119, leading to Fcomp≈100 kHz
which will ensure suitable PLL stability and speed.

问题：
从字面意思看，就是在设置R参数时，尽量往119靠，这样PLL可以比较稳定的工作，但是在需要设置多个频点时，
固定的R=119往往不够用，想请教一下，如果R值不设置为119,那么应该设置为比119大的值，还是比119小的值呢？

RF_002

Semtech官方有一个SX1212寄存器配置工具，它会自动选择最优的R、P、S参数，见附件

138****8538

RF_002 发表于 2019-6-20 20:05
Semtech官方有一个SX1212寄存器配置工具，它会自动选择最优的R、P、S参数，见附件 ...

感谢！这个没有配套的板子也能用吗？从手册上看要连板子
SX1212SKA Advanced Mode Software Installation
1- Put the CDROM in your computer and browse the contents of the CD.
2- Open the “sx1212starterkitsetup.exe” manually. It can be found in the \Installers sub directory of the CDROM.
3- Follow installation guidelines until the process is completed. Please note that .NET Framework 2.0 and the
FTDI USB driver will be automatically installed if not detected on your computer.
4- Connect the SX1212SKA board to the PC via the USB interface.
5- Launch “SX1212SKA” from the Start menu.
6- Click on “Connect” button in toolbar or in File menu.
7- SX1212SKA is now installed and ready to be used.

RF_002

如果只是利用这个工具生成相应的寄存器值，是不需要配套的板子的，打开工具后 按键 ”Ctrl+Alt+N“ 激活工具界面

138****8538

RF_002 发表于 2019-6-23 22:12
如果只是利用这个工具生成相应的寄存器值，是不需要配套的板子的，打开工具后 按键 ”Ctrl+Alt+N“ 激活工 ...

感谢！！