<HTML><FONT FACE=arial,helvetica><HTML><FONT SIZE=2 PTSIZE=10 FAMILY="SANSSERIF" FACE="Arial" LANG="0">In a message dated 1/10/2005 1:01:56 PM Eastern Standard Time, music.maker@gte.net writes:<BR>
<BR>
<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Being a 4046 PLL kind of guy, I have wondered about stability and tracking<BR>
when doing this. I have a PLL module that uses a divide by 12 counter in<BR>
the loop and it works just fine. But the MK50240 has a range from divide<BR>
by 239 to divide by 478. <BR>
<BR>
What kind of problems, if any, will there be with such large counters? <BR>
<BR>
I would think that proper VCO capacitor selection is important.<BR>
<BR>
Over/undershoot? <BR>
<BR>
Does a large counter affect lag very much? <BR>
<BR>
My own circuit has adjustable damping for the loop filter and allows me to<BR>
adjust it so that frequency changes are so immediate that I do not hear any<BR>
over/undershoot or lag. But then, my PLL has only a divide by 12 counter<BR>
in the loop.<BR>
</BLOCKQUOTE><BR>
<BR>
Per my earlier post, I built this circuit in the late 70's. Used it with a trumpet as input, also with an old Bee Gees Music Maker keyboard as input. Worked fine. No noticeable lag. I think I used the capacitor values from the frequency synthesizer circuit in the old RCA app notes for the 4046. <BR>
<BR>
Paul Camann</FONT></HTML>