| 摘要 |
<p>A Doherty amplifier including a carrier amplifier (8), and at least one peaking amplifier (10), a power divider (30) coupled between an input (2) of the power amplifier and inputs of said carrier amplifier and peaking amplifier, the power divider including a control (48, 50) for providing a control signal which is dependent on the magnitude of the input signal applied to the input of the power amplifier, and the power divider comprising a coupler, preferably first and second branch line couplers (32, 34), which are connected together via variable impedance means (varactors) (40) whose value is dependent on the value of the control signal, whereby as the magnitude of said input signal increases, the proportion of the input signal applied to the peaking amplifier increases, and the proportion of the input signal applied to the carrier amplifier decreases.</p> |
