Hi Guys.. I am try building a circuit which involves with a AD9854 DDS(Direct Digital Synthesis) chip to generate a frequency controlable sine wave for me... The problem for me is that the Master clock supply for the chip need to be around 200MHz...I don't know whether there is any crystal oscillator that can perform this function...or maybe there are some CMOS programmable oscillator chips that can do the trick for me...? Here is the link of the chip: http://www.analog.com/en/prod/0,2877,AD9854,00.html Thank you guys for ur help!!