| 摘要 |
A transmitter comprises a power amplifier (PA) with a power supply input (PI) and an output (PAO) to supply a transmission signal (Vo) with an output power (Po). A power supply (PS) has power supply outputs (PSO 1 , PSO 2 ) to supply a first power supply voltage (PV 1 ) with a first level and a second power supply voltage (PV 2 ) with a second level, higher than the first level. A switching circuit (SC) is arranged between the power supply outputs (PSOI, PSQ 2 ) and the power supply input (PI) to supply a selected one of the first power supply voltage (PV 1 ) or the second power supply voltage (PV 2 ) to the power amplifier (PA). A controller (CO) supplies a control signal to the switching circuit (SC) in response to a first power change command (PC) indicating a first desired level of the output power (Po), to supply the first power supply voltage (PV 1 ) to the power supply input (PI). The controller (CO) supplies the control signal to the switching circuit (SC) in response to a second power change command (PC) indicating a second desired level of t: 1 e output power (Po) and succeeding the first power change command (PC), to supply either the first power supply voltage (PV 1 ) or the second power supply voltage (PV 2 ) to the amplifier power supply input (PI) depending on values of said first desired level and said second desired level. The controller (CO) controls the power supply (PS) to vary a level of at least one of the power supply voltages (PV, PV 2 ) to always have available one of the power supply voltages with a level suitable for increasing the output power (P 0 ) substantially instantaneously. |
