SCHALTUNG FUER EINEN FARBFERNSEHEMPFAENGER

摘要

A television receiver can receive colour signal of the PAL system or the SECAM system. The change from one system to the other is automatic and without external switching. The television receiver can operate on signal from a first system of amplitude modulation and a second signal from another system of frequency modulation. A circuit processes the second signal, and has a frequency discriminator and an amplitude modulator. The frequency discriminator is tuned to a fixed frequency. This fixed frequency is equal to the sub-carrier frequency of non-modulated colour signal of the second system in alternating lines of the picture. A circuit is also used between the discriminator and the modulator. This circuit produces a constant signal for alternating lines.