R&D Report 1974-20 : Satellite broadcasting: channel separation requirements for FM television signals N.H.C. Gilchrist
A practical investigation has been conducted in order to determine the frequency separation required between FM television signals, both with and without a sound subcarrier, so that mutual interference is avoided. The investigation was concerned primarily with interference between PAL colour television signals, but brief tests were conducted to determine the requirements if PAL and SECAM signals were to occupy adjacent channels. It was found that a satellite broadcasting system based on EBU recommendations, with a receiver bandwidth of 27.5 MHz, requires a separation of at least 29.5 MHz between adjacent channels.