mjj@stda.jhuapl.edu (Marshall Jose) (07/18/89)
I've been trying to employ the Motorola 145151-1 PLL synthesizer chip to make a bunch of synthesizers, which I plan to use instead of crystals because of the crystals' cost and long shipping leadtime. I am finding that it is easy to build a synth, but hard to build a clean one. The circuit I'm using has a 9.102222 MHz reference oscillator divided by 8192 to give 1.111 kHz. The VCO operates at around 15 MHz, which when multiplied by 9 provides the receiver LO for the 2-meter band. Besides the usual reference signal sidebands at +/- 1.111 kHz, I am also seeing some about 66 kHz away. This sure ain't phase noise (is it)? Is there anybody out there with pointers on how to design them for clean operation? Remember, if you reply on the net, please limit the newsgroup above to the one in which you saw this. Thanks, Marshall Jose WA3VPZ mjj@aplvax.jhuapl.edu || ...mimsy!aplcen!aplvax!mjj