GPS Antenna Signatures
A handy way to characterize components is with a power signature. This is done by stimulating two points (usually a node and ground) with an a.c. test signal. When voltage is plotted on the X axis of an oscilloscope and current is plotted on the Y axis an unique signature results. The test signal is a triangle wave with just enough amplitude to bias a transistor. The following signatures are of GPS antennae.