| 摘要 |
378,662. Valve amplifying circuits. HAZELTINE CORPORATION, 15, Exchange Place, Jersey City, New Jersey, U.S.A.-(Assignees of Wheeler, H. A. ; 18, Melbourne Road, Great Neck, New York, U.S.A.) Sept. 4, 1931, No. 24850. Convention date, July 16. Class 40 (v).] A coupling system for use in a wireless receiver operating over two wave bands is arranged to operate with equal efficiency over the whole of each band. Fig. 1 shows an aerial coupling comprising primary windings 20, 21 resonant to frequencies below the lowest frequencies of the respective bands coupled magnetically and by capacity 19, in the sense shown in the drawing, to the secondary windings 22, 23. The inter-valve coupling comprises a primary winding 30 resonant to a frequency between the wave bands, coupled magnetically and by condenser 29 to the secondary windings. In a modification (Fig. 2 (not shown), the winding 20 of the aerial coupling is dispensed with and the primary is oppositely coupled to the secondaries and magnetic and additive capacitive couplings are used. Fig. 9 shows the construction of such a transformer the coupling capacity being provided by winding 18 which is provided at the required tapping point. |
