GB526368A - Improvements in or relating to electric circuit arrangements comprising a valve adapted simultaneously to generate and amplify oscillations of different frequency - Google Patents

Abstract

526,368. Valve circuits modulating systems. FIDES GES. FUR DIE VERWALTUNG UND VERWERTUNG VON GEWERBLICHEN. SCHUTZRECHTEN. March 14, 1939, No. 8187. Convention date, March 15, 1938. [Class 40 (v)] In a circuit in which a single valve is used both to generate an oscillation and amplify an oscillation of a different frequency, the output' circuit from which the amplified oscillation is obtained is so arranged that the generated oscillation is balanced out. The valve V generates a carrier frequency by virtue of the back coupling over transformer T2, the primary of which is tuned. The magnitude of the resultant feed back voltage on the grid of valve V is regulated by the tapping X on the secondary of transformer T2. Transformer T3, which is supplied with the modulating frequency, and rectifiers M form a carrier suppression modulator, so that side-band oscillations are supplied to the grid of V and amplified. The rectifiers M also act to limit the amplitude of the generated carrier. The secondary of transformer Tl in the valve anode circuit is connected in series with a second secondary winding of transformer T2 in such a fashion that the carrier frequency is neutralized and side-bands only are fed to the filter F which selects the required side-band for transmission. Figs. 2, 3 and 4 (not shown) are modified arrangements in which the carrier frequency is suppressed by means of a bridge output circuit. A modified form of carrier frequency feed-back circuit is employed in Fig. 4 (not shown). Fig. 5 (not shown) is a demodulating arrangement very similar to the arrangement of Fig 3. Specifications 407,404, 473,042, 485,993 are referred to.