| 摘要 |
<p>969,805. Amplifier circuits; antiside tone circuits. WINSTON ELECTRONICS Ltd. Aug. 6, 1963 [May 7, 1962], No. 17535/62. Headings H3T and H4R. A circuit for connecting between a 2-wire system and a 4-wire system comprises a constant current generator supplying a primary of a transformer in series with a resistor which supplies a receive amplifier, a secondary of the transformer supplying the receive amplifier in balanced opposition to the resistor supply and a tertiary winding of the transformer for connection to a line. A winding N2 feeds the input A2 of a receive amplifier via resistor R6 in balanced opposition to a feed from the collector circuit via capacitor C3 and resistor R5 so that an input at terminals A1, B1 is passed to line via a winding N3 and does not appear at terminal A2. An input on line winding N3 will appear only on the receive terminal A2. The opposition current may alternatively be supplied from the emitter circuit (complete Figure, not shown).</p> |
