TABLE 1 Compliance table of ITU requirements for DRM and IBOC systems Systems features Importance In the design Test status Expected completion DRM IBOC DRM IBOC DRM IBOC MW SW MW MW SW MW 1 System standard requirement a) Digital receiver should work worldwide A Yes Yes FUL FUL NYT 07/2002 2 Capability for a gradual transition from analogue to digital a) Simulcast (analogue and digital share a single channel) A Yes Yes (allows gradual transition between analogue and digital) FUL UND FUL 07/02 b) Multicast (analogue and digital occupy separate channels) A Yes (where administration allows such operation) Yes (where administration allows such operation) FUL FUL NYT 3 Data casting a) Audio and data i.e. data casting capability B Yes Yes FUL FUL FUL b) Provision of access control and scrambling C Yes (open issue) Yes (open issue) NYT NYT UND 03/03 03/03 07/02 4) Audio performance requirements a) Improve audio quality over that of equivalent analogue systems A Yes Yes FUL FUL FUL b) Multilanguage or dual mono B Yes No NYT NYT 07/02 07/02
TABLE 1 (end) Systems features Importance In the design Test status Expected completion DRM IBOC DRM IBOC DRM IBOC MW SW MW MW SW MW b) System complexity should allow low power consumption battery operated receivers B Yes (chipset technology allows it) Yes UND UND UND 06/03 06/03 06/03 10 Variable trade-off a) Possibility to select system parameters depending on broadcaster requirement B Yes Yes FUL FUL FUL Neither system A nor system B has finalized testing in LW. However, the results obtained in MW are probably representative for LW. The only possible bottleneck could be the antenna RF bandwidth. DSP: Digital signal processing FUL: Fully tested, therefore nothing is needed to be placed in the expected completion date NYT: Not yet tested UEP: Unequal error protection UND: Under way
Criterion 3 – Coverage area and graceful degradation Estimated actual coverage area for a given power level for the system under various propagation conditions. Coverage area will be defined as those surface area segments where the decoded signal is acceptable for the intended market. Criterion 4 – Compatibility with new and existing transmitters The ability to transmit the system waveform efficiently either: – currently available transmitter and antenna combinations with little or no modification required to the equipment; – transmitter and antenna equipment specifically designed to carry it; – transmitter and antenna equipment specifically designed to carry it and existing analogue formats. The ability of such configurations to operate with acceptable levels of spurious emissions. NOTE 1 – Many broadcasters will want or need to use their existing analogue broadcasting plant to carry the new digital services for a considerable time. Criterion 5 – Channel planning considerations Current channelization and interference rules will initially be important constraints even if studies and developments enable changes to be made in the future through the correct regulatory process. System possibilities therefore need at to be evaluated against existing rules for bandwidth occupancy, outofband emissions, spurious emissions, interference effects, etc. Criterion 6 – Single frequency network operation The ability of any new system to operate as a single frequency network needs to be assessed. Many broadcasters consider this to be a desirable feature. Criterion 7 – Receiver cost and complexity The possibility of both basic and advanced receivers needs to be considered. The receiver cost is obviously related to other criteria – an approximate cost estimate will be required for each criterion and variant. Criterion 8 – Interference The subjective and objective audio quality of the system operating with co- and/or adjacent channel interference from either digital or analogue sources. This should take into account both the ability of the signal to overcome interference in its own service areas and its propensity to interfere with other broadcasts outside it. Criterion 9 – Rapid tuning and channel acquisition Listeners are accustomed to little or no when switching on or tuning a radio receiver. The system design must therefore address: – the ease with which the listener can select the wanted station or signal; – the to acknowledge a request to select or change a channel; – the speed to acquire audio lock; – gaps (if any) in the signal when changing to an alternative or stronger source of the wanted signal.