| 摘要 |
An attenuator circuit ( 10 ) having two or more branch circuits ( 12 a to 12 e) has inputs ( 14 a to 14 e) for the branch circuits ( 12 a to 12 e) being connected essentially in parallel arrangement to an input port ( 20 ) for the attenuator circuit ( 10 ). Each branch circuit ( 12 a to 12 e) includes one or more bipolar transistors ( 32 a to 32 e) having a collector element receiving a signal from a power supply ( 24 ) through at least one RF positive-intrinsic-negative (PIN) diode ( 50 a- 50 d) that a control circuit ( 24 ) is controlling. At least one resistive element ( 16 a) couples an input ( 14 b) of a second ( 12 b) of the plurality of branch circuits ( 12 a to 12 e) from the input port ( 20 ) to the branch circuits ( 12 a to 12 e). Thus, each branch ( 12 a to 12 e) of the attenuator circuit ( 10 ) draws current from a low voltage power supply ( 24 ) while still providing for sequential biasing of successive branches and linearization of overall control characteristics.
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