| 摘要 |
495,455. Impedance networks. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., and GOODENOUGH, E. F. May 14, 1937, No. 13688. Addition to 410,499. [Class 40 (iii)] A tuned inductance and capacity are added to the coupling arm in that embodiment of the parent invention which is claimed in claim 7 of the parent Specification. Fig. 5 of the second Provisional Specification accompanying the parent Specification shows three meshes coupled by shunt capacities in combination with mutual inductances M1, M2, the effective shunt arms being tuned to the cut-off frequencies while the terminal-meshes are tuned to the midband frequency. According to the present invention, the leakage inductances which are effectively in the central series arm, and amount to (L2-M1) and (L3-M2) respectively, are neutralized by the insertion of additional inductance L5 such that the series arm is tuned to the mid-band frequency. The input impedance is made high, and the output combination C0, (L4-M2), may be slightly mistuned, to flatten the response at the middle and near the ends respectively of the pass band. The input leakage inductance (L1-M1) may be 30 or 40 per cent greater than the output leakage inductance L4-M2, while M1=M2. Instructions for trial-and-error adjustment are given and the effect of inherent resistance is considered in the Specification.
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