| 摘要 |
<p>846,705. Two-way transmissions. PINTSCHELECTRO G.m.b.H. Oct. 26, 1956, No. 32719/56. Class 40 (4). [Also in Group XL (b)] A hybrid circuit comprising three pairs of terminals and incorporating a differential transformer 1 also includes a resistive quadripole designed so that the impedance at all three pairs of terminals is identical so that the circuit may be used to connect a two-wire line to a four-wire line. The impedance z at a first pair of terminals i, k connected to the secondary of transformer 1, is half that 2z at the transformer terminals e, f. Said transformer terminals are connected to a matching resistive quadripole wl, w2 so selected that the impedance at the twowire terminals g, h, is also z. As the impedance at the terminals c, d, taken from the centre tap of the transformer, is z, the required conditions are satisfied. The quadripole in addition provides attenuation at terminals g, h to limit the transmitted signals. The network N balances the impedance 2z. In a modification, Fig. 5 (not shown) the transformer and quadripole are symmetrically designed with respect to earth and a resistance divider w3, w4, may be employed to produce a balanced network.</p> |
