2005: IBC Conference Award
Technical Papers: the excellence prize

This prize was awarded to Adam Wiewiorka and Peter Moss from BBC R&D Department for their paper 'Digital on-channel repeater for DAB'.

Professor David Crawford, Chairman of the IBC Technical Papers Committee explained "The assessors were particularly impressed with the balance between the complex mathematical theory of the subject and the practical implementation of a solution."

The on-channel repeater retransmits a signal on the same frequency as it receives, so that no frequency translation is required, as is the case in traditional rebroadcast or retransmission system.

In order to avoid instability caused by parasitic coupling between the receiving and transmitting antennas, an adaptive filter cancels stray transmitted signals. The challenge has been to provide sufficient cancellation. This is only now becoming feasible for broadband systems which have to operate in places where the feedback channel is continuously changing. Aircraft, birds, trees swaying in the breeze ­ they all create a highly variable feedback channel. It has taken state-of-the art digital techniques to implement the system.

BBC R&D White Paper WHP120:
Digital on-channel repeater for DAB
A. Wiewiorka and P.N. Moss

PowerPoint presentation: Digital on-channel repeater for DAB
A. Wiewiorka and P.N. Moss
File size: 1.3 Mb
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This technology is available to licence.