Implementation of direct digital synthesis in FM receiver system!!

[abhijitrc]

I have a few doubts related to implementation of DDS ( Direct Digital Synthesis) in place of conventional Fractional -N PLL in LO section of FM receiver. since phase noise is much better than PLL can we use DDS instead of PLL ?? Is the spurious of DDS is more than PLL ?? What is the effect of spurious of LO chain in the overall receiver system??? i have heard DDS have more spurious as compared to PLL !, is it???

Waiting for a technical suggestion.

 

[tony_lth]

Yes DDS has more spurious than PLL.They are about -60 or -70dbc and the spurious are much more than PLL.
It impact on the jitter of LO, so impact the final IF jitter.
There is some ways to calculate jitter from spurious, you can estimate with that.