What does single-ended symmetry mean in LC VCOs?

[CTT]

LC_VCO

Hello,

I read somewhere that "single-ended symmetry" improves 1/f noise
rejection for LC VCOs ... but what means "single-ended symmetry" ?
(sorry I'm no good english speaking person)

Thanks,

CTT

 

[DoctorX]

Re: LC_VCO

Hello,

I read somewhere that "single-ended symmetry" improves 1/f noise
rejection for LC VCOs ... but what means "single-ended symmetry" ?
(sorry I'm no good english speaking person)

Thanks,

CTT

I think that what they mean is "full differential" and "pseudo-differential". Full differential is the case where EVERY common-mode node in the circuit is floated as virtual ground, like the common-source in a differential pair.

Pseudo-differential is when you juxtapose (to place side by side) two single-ended circuit to give you a differential circuit.