| 摘要 |
1,102,408. Transistor amplifying circuits. RANK ORGANISATION Ltd. 28 May, 1965 [28 May, 1964], No. 22081/64. Heading H3T. In a transistor amplifier operating on two separated frequency bands, comprising as shown in Fig. 2, transistor Tr1 operating into series-connected parallel tuned circuits 21, 22, the arrangement is matched on both bands to the input impedance of a succeeding transistor amplifier Tr2 by means of a series capacitor Cc. To obtain a narrower bandwidth on the higher frequency band, for which tuned circuit 21 is used, the connection of the transistor Tr1 and capacitor Cc may be tapped down the inductor (Fig. 3, not shown). In a modification, the two tuned circuits comprise (1) for the higher frequency band, inductor L5, Fig. 4, tuned by capacitors C1, C2 in series, inductor L6 acting as a choke, and (2) for the lower frequency band, inductor L6 tuned by capacitors C1, C2 in parallel.
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