why CT delta-sigma modulator needs a DFF at its output?

[sapphire]

Looks like if there is not the DFF, the output will enter a limited-cycle osicllation? I am not sure how to express that meaning in a formal language. Thanks

Edward

 

[tdy]

can u post the diagram?

 

[sapphire]

the picture is quoted from temes' green book

 

[JoannesPaulus]

the comparator is not clocked, so the book is telling you that you need a clocked comparator to create a known delay in the loop.

 

[tdy]

after the clock introduced, the system becomes a 'controlled' sampling system, and the output is meaningful. it also has limited-cycle osicllation, cant avoid.

 

[sapphire]

Thanks all of you