Perhaps we should get Talbot to testify as to the difference. I'm sure he knows. He has more recent VCO patents that include the ring oscillator. For example patent 6445253.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6445253.PN.&OS=PN/6445253&RS=PN/6445253
Opty