World Broadcasting Unions Digital Radio User Manual - page 64

DIGITAL RADIO GUIDE

TERRESTRIAL TRANSMISSION SYSTEMS - ISSUES

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(SFN’s) to a greater or lesser extent and make it easier to extend coverage.  Provided

that a broadcast on the same frequency from a different transmitter, or a reflected

transmission from the main transmitter, arrive at the receive antenna within the system’s

guard interval, the reflected signal will combine in a constructive way to reinforce

reception.

One of the objectives for the Eureka 147 system was to transmit a digital signal (a

number of digitised analogue radio programmes plus data) to a mobile receiver over a

difficult transmission channel.  Extensive testing has confirmed that this requirement has 

been achieved successfully. The same characteristics of Eureka 147 ensure much more

rugged reception on portable receivers.

Recent development of IBOC systems in the US has also emphasised robust

performance in a multipath fading channel.  Using sophisticated signal processing

techniques such as Complementary Punctured Coding, along with time and frequency

diversity, the next-generation IBOC systems are expected to exhibit fading channel

performance commensurate with that achieved in the Eureka 147 system, but this

remains to be demonstrated.

Tests and operational broadcasting have shown that DRM coverage is equivalent to the

corresponding analogue service it is replacing. Coverage, in this sense, refers to the

intended broadcast area, wherein the digital signal retains its high audio quality.