GB293839A - Improvements in or relating to heterodyne radio receiving systems and apparatus for use therein - Google Patents

Abstract

293,839. Regnauld de Bellescize, H. J. J. M. de. July 13, 1927, [Convention date]. Thermionic heterodyne receivers. - A four - electrode valve has its inner grid 6 connected to the local oscillator, its outer grid 7 being connected to the wavereceiving circuit and through a variable coupling 11 - - 13 to the local oscillator The tuned circuit 2 of the local oscillator has the points 9, 10 at opposite potentials connected to fixed condenser plates 12, 13, the movable vane 11 being connected to the outer grid 7 to supply oscillations of either phase thereto. A two-fold heterodyne effect is obtained due (1) to the superposition of the two waves in the circuit of the grid 7 and (2) to the application of one of the waves to each grid 6, 7. If the local wave is shorter than the incoming wave, the two effects are additive when the plate 11 is coupled to the plate 13. and tend to neutralize each other when the plates 11, 12 are coupled. With the local wave longer than the incoming wave, the reverse conditions obtain. In a modification, (Fig. 2, not shown) the local wave is generated by the four-electrode valve, the tuned circuit 2 being connected between the plate 8 and the inner grid 6.