ANALOG ADVENTURES

Although it is common to synonymize (is that a word?) analog with linear, there are many nonlinear analog functions, the most common being the logarithmic amplifier. In our last installment, we explored the Gilbert Cell, a most useful non-linear analog building block. As a four-quadrant multiplier, the Gilbert Cell adds the logarithms of the applied signals to create the product of those signals … just as a slide rule (Photo A in case you’re too young to remember them) adds logarithms to achieve multiplication.

I suppose we should do a whole article or two on slide rules, since one can