Shortwave is an efficient technology for delivering programming to a wide area from a single transmission site, but FM provides higher quality audio and a ready supply of inexpensive receivers. At IBC2011, Thomson Broadcast is demonstrating a solution that bridges the two technologies, using the DRM30 digital radio standard to distribute programming for retransmission on FM.
With the system, a broadcaster originating a DRM30-encoded short-, long- or medium-wave signal could take the same over-the-air signal listeners with a DRM receiver can hear and, using a DRM-FM transponer, demodulate and transpose it to an FM signal that can be picked up by an standard FM receiver, including the sort common in many mobile phones.
For example, a medium-wave channel with a bandwidth of 9 kHz could be used to distribute two DRM30 digital audio programs at a bitrate of up to 14.7 kbps; if the channel is extended to 18 kHz, bitrates of up to 26.5 kbps would be possible.
The DRM-FM rebroadcasting transmitter takes the over-the-air DRM30 signal, decodes the digital programs and then can retransmit the two services locally on FM.
The system could be used by NGOs or international broadcasters to distribute programming to low-power FM stations in remote or wide-spread areas without the need to use satellite connections.
(radioworld.com)
