Thanks for the reply, I am refering to the "Design of Analog CMOS integrated circuits" by Razavi, Chapter 14 Oscillators.
If you see in page Number 520 (Also in Page 514), under the wide tuning range section, he says that the present configuration doesnt provide more than 3 to 1 tuning range. I am not able to understand this sentence.
Prakash.
Added after 7 minutes:
I have attched the images of the sentences for your refernce.