pic frequency generator
Generating sine wave in this range is not easy task ..
However, you can employ MAX038 function generator (see picture/file below), set S2 to SIN output, replace S1 switch with CD4066 CMOS switches controlled by a PIC (range selection), and, for fine tunning (you can use buttons for frequency increase/decrease), replace VR1 and VR3 by digitally controlled potentiometers controlled by the same PIC ..
For more details on the MAX038 IC goto:
**broken link removed**
(try to ask MAXIM for free samples)
Regards,
IanP