Oscillator for VHF TV receiver - has RL circuit ensuring synchronism between oscillator and receive frequency over entire tuning range

摘要

The oscillator circuit has a series circuit consisting of a capacitor(14) and a variable inductor(15) connected to a junction between the inductors(3, 4) in the oscillator resonant circuit(1) and to earth. This ensures that the receive frequency and the oscillator frequency are synchronised over the entire width of the tuning range. The oscillator resonant circuit consists of a varactor diode(2) shunted by the two series inductors(3, 4), one of which is variable. A ferrite core(13) is connected between the tapping between these inductors and the series circuit capacitor(14) in order to damp the series circuit.