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Design >> RF Design >> differential/doubly balanced circuits
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Message started by vikasv on Jul 12^th, 2003, 3:51pm

Title: differential/doubly balanced circuits
Post by vikasv on Jul 12^th, 2003, 3:51pm

hello,
I am new to the field of RF circuit design and simulations.
My question is regarding measurement of conversion gain for differential/doubly balanced circuits.
In a gilbert cell mixer(or any other doubly balanced circuit) what does lo+, lo-,rf+, rf- imply. Are these separate (antiphase) voltage sources(ports)
or single voltage source connected between the positve and -ve terminals. Also by the same logic do i need to connect a single port between if+ and if- or separate ports.
Secondly, if these are separate, then the actual conversion gain should be
((if+) - (if-))/((rf+) -(rf-)). Through spectre -RF i can get only
((if+) - (if-)) / rf+ or ((if+) - (if-))/rf-
{ pxf1 (if+ if-) pxf ...... and selecting i/p node rf+ or rf-}
So do i need to manually do the conversion ??
Will symmetry play a part and can if+/rf+ be taken as conversion gain.