| A | B |
|---|
| Radio waves | High frequency alternating current (AC) signals |
| Amplification | An increase in the amplitude of a RF signal |
| Wavelength | Is the distance between identical points in the adjacent cycles of a waveform signal propagated in space or along a wire. |
| Gain | Refers to the amount that a signal is amplified |
| Loss | The bending of radio waves as they pass through medium of a different density, such as going through air, and then through glass |
| Diffraction | Describes a radio wave bending around an obstacle that has sharp irregularities or a rough surface |
| Scattering | Describes radio waves that upon striking a uneven surface are reflected in multiple directions at once |
| Intentional Radiator | An RF device and all cabling up to but not including the antenna |
| Equivalent Isotropic Radiated Power (EIRP | The power radiated by the antenna |
| Modulation | Refers to the process of encoding information onto a carrier signal |
| Narrowband signal | These signals use only the amount of the frequency spectrum to carry a data signal |
| Spread Spectrum Technologies | These take a narrowband radio signal and spread it out across a much wider bandwidth for transmission |
| Direct Sequence Spread Spectrum (DSSS or DS) | A technique in which pseudo-random sequence directly phase modulates a carrier signal |
| Frequency Hopping Spread Spectrum (FSSS or FS) | Uses a narrowband carrier that changes frequencies in patterns called a hopping pattern, that are known to both the transmitter and receiver, so it appears to be a single channel |
| Orthogonal Frequency-Division Multiplexing (OFDM) | A multi-carrier modulation technique that uses orthogonal, or non-interfering, carrier signals to divide a frequency-selective channel into a number of narrowband channels |
| Impedance mismatch | Occurs for example, if the cable leading to the antenna is 50 ohms and the connector to the antenna is 75 ohms |
| Visual LOS | The unobstructed path between two points such as a transmitter and a receiver |
| Fresnel Zone | The area around the visual LOS, often referred to as RF line of sight |
