Does DRM have a “simulcast” mode that allows simultaneous transmission of analogue and digital signals in the same channel and will existing analogue receivers work with it?
A number of simulcast modes are detailed in the DRM system specification. In some of these the analogue signal is transmitted as a single sideband signal with a carrier, in others as a full DSB signal. The option that might be used will depend on the bandwidth which is available either side of the channel. If these simulcast modes are used then existing analogue receivers will be capable of receiving the analogue signal. DRM30 supports both single channel simulcast and double channel simulcast. Single channel simulcast describes a signal which carries both an analogue (SSB) and a digital signal component (half channel, 4.5/5 kHz) within one 9 or 10 kHz broadcast channel. Although this setup allows both a compatible analogue and digital signal in a single channel, unless the channel is very flat (e.g. an LF channel) tilt will degrade the AM quality and since there is only a half channel for the DRM, the audio quality of the digital signal will be poor. Double channel simulcast, however,
Related Questions
- What happens during the period of simultaneous analogue and digital terrestrial broadcasting, commonly known as simulcast?
- If KFVS12 is transmitting analog and digital signals until June 12th, 2009, are they both on the same channel?
- Why can more information be carried by digital signals than analogue signals?
