Abstract
Digital
radio cameras (wireless television cameras) are beginning
to be used in the BBC for making a wide range of
television programmes. They have the advantage over
analogue radio cameras in that they have a greater
immunity to multipath and interference. This ruggedness
comes from the use of the DVB-T (Digital Video Broadcasting – Terrestrial)
modulation standard developed for digital television.
However, to maintain a high picture quality, while
minimising video coding delay, a high bit rate is
transmitted.
Programme
makers are experimenting with using digital radio
cameras where analogue radio cameras would not normally
be considered, such as in television studios. This
expansion of use comes at a time when the 2.5GHz
band will soon be reallocated to 3G mobile telephony
and so suitable alternative spectrum will be needed
for digital radio cameras.
The
technology behind digital radio cameras is outlined,
concentrating on the design compromises that have
an impact on spectrum usage. Future trends in the
development of digital radio cameras by the broadcast
industry are also discussed.
The
various applications for digital radio cameras will
be described indicating the numbers of cameras involved
in order to indicate the spectrum requirements. Results
from measurements carried out in collaboration with
the RA and JFMG Ltd to assess the feasibility of
sharing with unlicensed users in the 2.4GHz are outlined.
This
document was originally given in London at an IEE
conference “Getting the Most Out of the Radio
Spectrum” 24-25 October 2002. IEE 2002/112. |
