9/11/'98


Hey Starfiire,

Want to do a PLL, GOOD!


1/      The loop filter is important so spend some time with this.
2/      Spend the money on a good referance you will require 10ppm for VHF.
Nominaly this referance will be 10MHz
3/      Use seperate clock and data lines to the PLL and decouple via RCs to
stop phase noise
4/      Use seperate and well decoupled power supplies for the PLL and PIC
5/      Use one common ground point for both!
6/      Use ground planes!
7/      Keep all leads short to minimise RF currents that may flow!
8/      Try to keep the lock time in the sub 30mS area
9/      Always monitor the lock of the PLL and DON'T attempt to relaod
unless it         is not locked.
10/     Decide if the frequency for the AMRC values are calculated or stored
(Stored via a look up table is easyest, this can be in the FLASH section of
an F84 so that it can be re-programmed)
11/     Get some one with RF experiance to help.
12/     Philips have a good loop filter programme that will save some time
13/     Varil give very good and simple formulee to calculate the values in
thier app notes


Better tell us exactly what you want, from the programming side things are
simple, but the hardware side is not.


Dennis