GB240848A - Means for the grid back coupling of valve transmitters - Google Patents

Abstract

240,848. Telefunken Ges f³r Drahtlose Telegraphie. Oct. 1, 1924, [Convention date]. Thermionic generators. - In order to avoid the necessity for alterations of the back coupling when the wave-length of the oscillator is varied, the grid coil is tightly coupled to a coil which is subjected to the oscillatory plate voltage but does not form part of the main oscillatory circuit. As shown in Fig. 1, the grid coil h forms the secondary coil of a transformer, the primary g of which is connected between the points x, y subject to the plate oscillatory voltage. The oscillatory circuit b, c may have tappings p, q for varying the plate connection and the tuning respectively. A block condenser d and a high-frequency choke e are provided as usual. In a further modification shown in Fig. 3, the choke is in two halves g<1>, g<2> forming jointly the primary winding of a transformer, the secondary h being in the grid circuit. The connection to the oscillaaory circuit b, c is taken from a point between the two halves g<1>, g<2>. The Specification as open to inspection under Sect. 91 (3) (a) refers to an arrangement in which the grid coil h is tightly coupled to the choke e, and the additional coil g is omitted. This subject-matter does not appear in the Specification as accepted.