The vestigial-sideband filter for the Sutton Coldfield television station

The paper is concerned with the design, construction and performance of the vestigial-sideband filter circuit installed at the Sutton Coldfield television station in 1949, operating on a vision carrier-frequency of 61.75 Mc/s and a sound carrier-frequency of 58.25 Mc/s. An outline of the specification of the filter is given as well as the reason for the choice of a complementary constant-resistance network filter of the Norton typs for this purpose. The basic design formulae relevant to the network chosen are given, with information on the inversion and replacement of lumped elements by coaxial lines. The practical circuit adopted is given, as well as the measured results showing the agreement between its performance and that of the idealized network. Finally, reference is made to the construction of the filter and to the ancillary components of the installation, comprising the absorber load, the standing-wave detector and the change-over switch.