| 摘要 |
625,121. Thermionic valves. SYLVANIA ELECTRIC PRODUCTS, Inc. Aug. 6, 1946, No. 23312. Convention date, Feb. 14, 1942. [Class 39 (i)] [Also in Group XL (c)] In an R.F. mixing system two oscillations to be heterodyned are applied in push-pull to opposite ends of a pair of input electrodes of a double valve and the beat frequency is taken off by means of a tuned circuit common to two output electrodes of the valve. The Figure shows an arrangement in which the two frequencies to be heterodyned are applied to quarter-wave lines 53, 54 and 55, 56, whose unshorted ends are connected to opposite ends of grids 49 and 51 of a double triode, the anodes of which are connected through resonant circuit 69, 70, 75 tuned the difference frequency to the H.T. supply. The connections from the two R.F. sources 62 and 65 to the resonant lines are made through contacts 63, 64 and 66, 67 made adjustable to facilitate matching. Fig. 5 shows a plan view of a suitable double triode assembly consisting of two triode units 50 and 52 mounted on a glass base and having their cathodes and anodes interconnected. The double triode may be replaced by a double diode in which case the diode anodes are connected in the same manner as the triode grids and the circuit tuned to the intermediate frequency is placed in the common cathode circuit. Specification 616,889 is referred to. |
