National Transcommunications Ltd, formerly the transmitter operator and technical arm of the UK’s now-defunct Independent Broadcasting Authority, now managed for institutional investors by Mercury Asset Management Ltd, claims a breakthrough in digital television transmission, which according to the Wall Street Journal is arousing considerable interest: the system breaks up the digital signal into 432 separate subsignals, each of which modulates a different low-power carrier, with the receiver reassembling the signals to make up the picture and sound; taking advantage of the capability of scrambled digital signals to be reconstructed using error detection and correction techniques, the system reduces the power required for transmissions covering a given footprint compared with analogue transmissions, and can also be transmitted alongside analogue signals without interfering with them.
