At IBC during the Nautel event, RFmondial together with Nautel demonstrated its advanced multiplexed DRM modulation for the FM band, that allows broadcasters to transmit multiple DRM channels on one physical transmitter.
The newest member of RFmondial’s successful LV-series of DRM modulators and exciters allows the parallel generation and transmission of up to six pure digital DRM channels, or in combined analogue and digital „Simulcast” mode, one traditional analogue FM channel and up to four DRM channels.
As explained by Stefan Galler, Managing Director of RFmondial GmbH in Hannover “using a spectrum of 600kHz one could place the FM signal occupying 200kHz in the centre and use the other 400 to carry two right and two left DRM channels or just two right or left DRM channels as DRM occupies half the FM spectrum. One DRM channel carries two to three programmes so on one transmitter, one antenna one could broadcast in pure DRM up 24 programmes, probably a bit too ambitious or one FM programme and between 12-18 DRM programmes.”
The efficiency is not just at the spectrum level but comes also from the possibility of reusing the same transmitter, the same antenna and combiner systems. Planners will appreciate that if you wanted to put two DRM channels on adjacent frequencies this was very hard and for good results you needed really to build two towers and two antennas. With this innovation using one transmission site and one antenna is possible, easier, bringing in efficiency and a degree of flexibility unknown before. In Stefan Galler’s words: “The ability to freely mix and combine analogue and multiple digital DRM signals, in adjacent channels, with individually varying power levels, supporting single frequency networks, allows broadcasters, network regulators and frequency planers a new dimension of possibilities for planning and operation of digital radio networks.”
Notes: Press Release – DRM Consortium – September 25, 2019