| 摘要 |
A receiver including an rf amplifier (14) having an input, an output and a gain control input (38), means (34-not shown) for deriving a gain control signal and gain control means (36) responsive to the gain control signal for applying a gain setting signal to said gain control input (38). The gain control means (36) comprises at least 2 parallel arranged bias current means (40, 42, 44), at least one (42 or 44) of said at least 2 bias current means including switching means (SW1 or SW2) responsive to a control voltage varying by a predetermined amount relative to a reference voltage (Vref1 or Vref2) for actuating the switching means (SW1 or SW2) to connect or disconnect the bias current means (42 or 44) to or from the gain control input. |
