| 摘要 |
1,241,747. Selecting the intermediate of three signals. BODENSEEWERK GERATETECHNIK G.m.b.H. 25 Sept., 1969 [10 Oct., 1968], No. 47310/69. Heading H3T. [Also in Division G3] A circuit for selecting from three input signals that having the intermediate value, for use for example in redundant type aircraft pilot systems comprises an amplifier in each channel feeding a diode logic circuit which selects the intermediate signal, negative feedback being applied from the output to each amplifier input. In Fig. 1, if -E 1 >-E 2 >-E 3 the voltages at X+Y are E 1 and at Y 1 E 2 .D 81 is therefore conducting and D 71 +D 91 blocked. Accordingly E 2 , the intermediate value appears at E A . Negative feedback is provided from E A to each input. In Fig. 4, if the input voltages are as shown, E 2 again being the intermediate value, the voltages at the points following the amplifiers also have the voltages shown, the + 15V and -15V at the output of V 1 and V 2 resulting from these two amplifiers being driven to positive or negative saturation by the feedback from the common output. The diodes shown in black conduct and those open are cut-off so that the intermediate input appears at the output. Preferably resistors R 1 -R 6 are of the constant-current type. |
