Digital Circuit Boards: Mach 1 GHz

2.24 Glossary

Cascaded transmission lines (Section 2.16): Transmission lines in series.

Characteristic impedance (Section 2.4): The ratio between voltage and current associated with a wave traveling on a transmission line. The square root of the ratio of inductance to capacitance per unit length of a transmission line or (L/C)^1/2.

Clamping action (Section 2.10): Diodes that are placed on integrated circuit connections to protect the circuit from over or under voltages. It is wise to design logic circuits so this diode action is not used.

Common-mode signal: The average voltage on a group of conductors measured with respect to the receiving common conductor (ground).

Decoupling capacitor (Section 2.12): A capacitor that stores field energy that is mounted near or at a component to supply transmission line energy when logic switching takes place.

Embedded microstrip (Section 2.3): Traces on the outer layer of a circuit board that are embedded in a dielectric. This practice has many benefits in short rise time logic.

Even mode (Section 2.3): A signal that is common to a pair of signal traces (differential pair). For differential signaling, the even-mode signal is an unwanted signal often called the common-mode signal. The receiving logic is designed to reject this part of the incoming signal and respond to the normal mode (odd mode) part of the signal.

Exponential (Section 2.11): A process that involves factors of e^αt, where e is the base of natural logarithms and t is the time.