[sdiy] Phase-locked loops and the root of my headache

[Jon Darby]

Howdy, everyone!
    I would really appreciate it if someone could give me (us?) an overview
of PLLs and their audio applications, particularly the 4046A PLL with VCO
chip. At $1.02 a pop I had to pick one up to play with it, but do not
understand exactly what a phase locked loop is. Reading the data sheet on
the 74HCT4046, it appears the the three different comparators are not
inteded to be used simultaneously?  Does the frequency or whatever is fed
into teh comparator input control the frequency of oscillation of the VCO?
If so, would an external master oscillator drive the PLL's range that it
allows the VCO to oscillate within? Uggh, I'm talking out of my rear at this
point. If anyone has a pointer or two where to start to understand PLLs or
little projects I could do with this beast for fun fun audio fun it would
really be swell.

Your pal,
Jon Darby