| 摘要 |
PURPOSE:To improve characteristics of a balanced amplifier by making one DC cutoff each between input terminals and output terminals of one hybrid and by making connections at the cutoffs after testing static characteristics of FET separately. CONSTITUTION:Between input terminals 91, and 92, and output terminals 93 and 94 of output-side hybrid 9, cutoffs 25 and 26 for DC disconnections are made, respectively. To test static characteristics of FET7' in the said state, input terminal 92 of hybrid 9 is connected to DC power source VD via lead line 23. Consequently, a current flows only to the the drain of FET7' and never flows to FET7 because of the cuts. After the static characteristics of FET7' are tested, lead line 23 is connected to the input terminal of hybrid 9 to test static characteristics of FET7. After those tests, connections at those cutoffs are made in terms of direct current and high frequency to improve characteristics of the balanced amplifier. |
