Editing unit for sound films - has auxiliary detector head in circuit with optical coupler connected to main film unit and with separate amplifier for auxiliary projector

摘要

The sound film unit is used for sound editing of films and has an auxiliary replay-head (12) associated with an amplifier (14) with a variable gain factor. The film is monitored in conjunction with a display device with a lamp (33) illuminating an auxiliary objective (32) with an optical axis parallel with that of the main projection system (4). The lamp is connected in the output circuit of an additional amplifier (35), supplied on the input side by a photo-resistor (36) an and a light-diode (30) forming an opto-coupler (37) in circuit with the control circuit (15, 16, 40) of the auxiliary pick-up head (12). The editing circuit is powered by a battery and an h.f. oscillator is used to control the operation of the amplifier.