| 摘要 |
An RF transmitter with improved efficiency and good linearity decomposes an input AM signal into two signal envelopes with phased modulation at a phase angle theta. The transmitter has three principal embodiments. A first solution uses at least one added RF amplifier for each decomposed signal envelope with one or more amplifiers having a low gain compared to that of a high gain amplifier in another branch for the same signal envelope. A phase angle thetai is determined that corresponds to a switching on two of the 2n+2 total branches, n=0, 1, 2, . . . . A second solution uses the same general schematic architecture as the classic LINC system that requires only two RF amplifiers, but uses a different decomposition because the two RF amplifiers are used in their nonlinear zone. The decomposed signal envelopes can be variable. The amplified output signal allows the combiner to be used at 100% efficiency in major part of signal. The third solution combines the first and second solutions.
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