H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
H03F1/42—Modifications of amplifiers to extend the bandwidth
H03F1/48—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers
H03F1/50—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers with tubes only
H—ELECTRICITY
H01—ELECTRIC ELEMENTS
H01C—RESISTORS
H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
Dispositif correcteur d'un signal vidéofréquence de télévision par atténuation dynamique du niveau du bruit, et source d'images de télévision comportant un tel dispositif