The 4046 has two phase comparators and one of them will work ok (phase comp. #2). Actually #1 may give lower distortion but it may jump frequency easily. C1 should be in uF with R in KOhms and F in kHz ? I hate mixed unit formulas. You want to calculate the loop for dF +/- 10kHz (I think ? check numbers for SCA). Then use a frequency defining cap calculated using a resistor on pin12 (neglect the loop and pll output). You may want to use a 220pF frequency set cap (pins 6,7), a 1M pot from pin12 to gnd to set center frequency (tune) and 62K + 1n8 loop filter components between pin13 pin9 and gnd. Audio out is pin10 using pulldown 47K or 62K, about 100mV pk-pk with some carrier residue. If the distorsion becomes unacceptable (over 5%) then add a 470K resistor between pin13 and GND. Peter -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu