| 摘要 |
875,250. Valve frequency selective amplifying circuits. MARCONI'S WIRELESS TELEGRAPH CO. Ltd. March 22, 1960 [Oct. 15, 1959], No. 34961/59. Class 40(6) In a very high frequency amplifier having an input circuit comprising two transmission lines T 1 , T 2 , each an odd number of quarter wavelengths of the mid-band frequency in length, and the line T 1 comprising the electrode leads of the valve V and line T4, a short circuited transmission line T3 also an odd number of quarter wavelengths in length is connected to the junction of lines T 1 , T 2 to render the input impedance at terminals 1 substantially purely resistive over a wide frequency band. The shaded portions of line T 2 , T 4 connected to the grid of valve V is constituted by an earth plane. An arrangement for a directly heated cathode is described with reference to Fig: 2 (not shown). |
