Glossary of Key Terms
Glossary of Key Terms
| Term | Definition |
| 4-DPSK OFDM | A modulation scheme used by Digital System A, combining differential phase shift keying with orthogonal frequency division multiplexing to meet requirements for high bit-rate digital broadcasting, especially in multipath environments. |
| ARIB | Association of Radio Industries and Businesses, the organization that developed Digital System E. |
| BSS (sound) | Broadcasting-Satellite Service (sound), referring to digital sound broadcasting services delivered via satellite. |
| CDM | Code Division Multiplex. A technique used in Digital System E, where different broadcasters use different orthogonal codes for spreading the signal. |
| COFDM | Coded Orthogonal Frequency Division Multiplex. The modulation scheme used in Digital System A, which is particularly robust in multipath environments. |
| Diversity | Techniques used to mitigate fading and signal loss by providing the receiver with multiple versions of the same signal. This includes time diversity (retransmission), reception/space diversity (multiple antennas/receivers), and transmission diversity (multiple frequencies). |
| Eureka 147 DAB | Digital Audio Broadcasting. The consortium and standard that developed Digital System A. |
| FEC | Forward Error Correction. Coding techniques (e.g., convolutional, Reed-Solomon) that add redundancy to transmitted data, allowing the receiver to detect and correct errors without retransmission. |
| Gap-filler | A terrestrial repeater used in Digital System E to retransmit the satellite signal to cover areas blocked by obstacles, such as buildings. They can be direct-amplifying or frequency-converting. |
| ITU-R | The Radiocommunication Sector of the International Telecommunication Union. |
| MCM | Multi-carrier modulation. A multipath-resistant orthogonal frequency division multiplex technique used by the terrestrial component of Digital System D<sub>H</sub>. |
| MPEG-2 AAC | MPEG-2 Advanced Audio Coding. The audio source coding selected for Digital System E, noted for its efficient audio compression performance for high-quality audio broadcasting. |
| MPEG-Audio Layer II | The audio source encoding method used by Digital System A, also known as the MUSICAM system. |
| MPEG-Audio Layer III | The audio source encoding method used by Digital System D<sub>S</sub>, widely used for digital sound broadcasting. |
| OSI Basic reference model | Open Systems Interconnection model. A conceptual framework used in the description of Digital System A to structure the system into distinct functional layers (e.g., Physical, Data Link, Network, Transport, Session, Presentation, Application). |
| PAD (Programme-associated data) | Data, such as text or graphics, which is linked to a specific audio programme and carried within the same multiplex. |
| QPSK | Quadrature Phase Shift Keying. A digital modulation scheme used by multiple systems (B, D<sub>S</sub>, D<sub>H</sub>, E) for transmitting data. |
| RAKE receiver | A receiver designed to counter the effects of multipath fading. It uses several sub-receivers to “rake” in and combine the signal components arriving at slightly different times, as mentioned in the context of Digital System E. |
| TDM | Time Division Multiplex. A method of transmitting multiple signals or data streams over a common channel by assigning each stream a different time slot. It is a core component of Systems D<sub>S</sub> and D<sub>H</sub>. |
| WARC-92 | The World Administrative Radio Conference held in Malaga-Torremolinos in 1992, which allocated frequency bands for BSS (sound). |