Automatic vector impedance measurement with minimum hardware

A computer-based technique for vector impedance measurement is described. An alternating voltage of specified frequency is impressed across a series combination of the unknown impedance Z and a reference resistance R0,; the voltage to ground and the phase angle at the nodal connection are then measured and recorded. Measurements are repeated after interchanging Z and R0, and the magnitude and phase of Z and R0 are automatically calculated. Alternatively, Z and R0 are not interchanged, so that the amount of hardware is reduced at the expense of a software algorithm for determining |Z| and ¿. This trade-off simplifies the design and makes it more cost effective.