| 摘要 |
A Doherty amplifier (10) is operable to receive an input signal (Pin) and to provide an amplified output signal (Pout) at an amplifier output (95). The Doherty amplifier (10) comprises: first (30) and second (40) amplifier stages, each amplifier stage being switchable between an amplifying and a non-amplifying state, each amplifier stage being arranged in parallel to receive the input signal (Pin) and, in the amplifying state, to provide a respective amplified signal at a respective amplifier stage output; and an output network (50) comprising first (80) and second (90) impedance transformers, each impedance transformer being coupled at a first side with a respective amplifier stage output and being coupled together in parallel at a second side with the amplifier output (95). By using an alternative, parallel architecture, the impedance transformation ratio experienced by an amplified signal under different operating conditions is significantly reduced compared to that of a traditional architecture which uses a single, series, impedance transformer which combines and transforms the amplified signals from both amplifier stages (30, 40). |
