| 主权项 |
1. An amplifier system comprising:
a main amplifier configured to amplify an in-phase signal during a low power mode and a high power mode, and a peak amplifier configured to amplify a quadrature signal in the high power mode and present a predetermined output impedance is the low power mode; an impedance matching network coupled to at least the peak power amplifier; and an impedance transformation device coupled to at least a portion of the impedance matching network, the impedance transformation device being configured as a balun in the high power mode, the balun including a first input and second input coupled to the main amplifier and the peak amplifier respectively, the impedance transformation device being configured as an unbalanced line impedance transformer in the low power mode whereby the predetermined output impedance substantially grounds the second input, the Doherty device being characterized by an impedance transformation ratio of at least 4:1 and a relative bandwidth greater than or equal to 40%. |
