Hi Ron H,Lkgan, If you can be happy with a tunable filter that will not work past 100kHz, have a look at LMF100. You probably won't find a simpler way to tune a filter. Tuning is done by varying the clock frequency.
I scanned through the LMF100 document, I don't quite understand how the block diagram works. You mean the bandwidth or cut-off frequency of the filter can be tune by varying the clock frequency? Is the LMF100 applicable for PLL?
Thanks for introducing something new for me, but it's not controllable, unless you got some ways to do it?Take a look at GYRATOR CIRCUITS , ask google about it.
good luck
Lineman