Digital television transmission in the terrestrial UHF band

A major research programme, known as SPECTRE (Special Purpose Extra Channels for Terrestrial Resolution Enhancements), is investigating the most efficient use of the entire terrestrial broadcasting path, by using digital techniques to exploit as much as possible of the redundancy inherent in the current network. This is being achieved in several ways: (i) a low bit-rate picture coding system operates by removing as much statistical and psychovisual redundancy as possible from the pictures prior to transmission; (ii) the spectral properties of the modulation ensure that the available channel capacity is fully utilised; (iii) the rugged interference properties of the modulated signal at very low signal power, should permit transmission in the redundant `taboo´ channels which are currently restricted from use