Tuner design considerations for a combined 405/625 line television receiver

U.h.f. tuner design is comparatively standardized except for means of meeting the probable requirement of 60 dB image signal rejection. The system of feeding the u.h.f. tuner into the v.h.f. stage by directly coupling to the mixer grid appears to be the logical approach, bearing in mind both technical and commercial considerations. The general design requirements to meet the use of u.h.f. in combined receivers are com paratively straightforward. The only outstanding problem is that of the eventual v.h.f. system and a scheme for meeting the likely changeover to C.C.I.R. channel allocations is put forward.