puzzled with a mos device in a vco

[jasonxilion]

hello all
recently i am dealing with a vco, i paste it on the web, can u see?

it is a delay cell, vc is the contral voltage of the vco. i think most of u are familiar with this kind of vco.

my QUESTION is : why the gate of MNC be connected to vdd, to operate in triode region?

a paper says that it allows the full amplitude of oscillated signal within a wide range. but i don't know why. anyone can tell me why?

and more, what the effect of the MNC to the phase noise of vco?

 

[AdvaRes]

Please upload the paper from which you get that delay cell. Maybe after ater analysing it I can help you.

 

[jecyhale]

I never use this kind of VCO. I think if you remove the MNC, the amplitude range will be larger.
Maybe it is good for phase noise.
But it works as resistor, how to reduce the noise?