A method of realizing monolithic variable linear circuit elements is presen
ted. The method exploits monolithic variable gain amplifiers to modify the
values of passive integrated devices. The technique described herein realiz
es floating true two-terminal variable elements. A theoretical analysis of
a variable capacitance cell is performed as a prelude to a practical design
producing capacitances in the range of 4 pF to 30 pF. The results of theor
etical analyses are compared to SPICE [1] simulations of the subject cell,
prototype circuit results are presented, and performance limitations are di
scussed.