| 摘要 |
A low noise amplifier with switchable gain settings comprises a cascoded emitter coupled pair (T1, T2, T5, T6; T3, T4, T7, T8) having a current diverter (T9, T10) which reduces the gain to an intermediate level in response to a control signal on terminals (8, 9). Further control signals on terminals (5, 10, 11, 12, 13) reduce the gain to a low level by introducing emitter degeneration (R3). To compensate for the increase in input impedance caused by the introduction of emitter degeneration feedback loops (C1, R8; C2, R9) are connected between the diversion path and the amplifier inputs.
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