| 摘要 |
An RF power amplifier for a polar transmitter converts (60, 180) an amplitude component signal into a 1-bit digital amplitude signal, which is fed to a digital finite impulse response filter (20). Successive taps of the filter each have an RF amplification stage (40, 120, 130, 140, 150, 160, 165, 170) arranged to amplify successively delayed versions of the 1-bit digital amplitude signal, the amplifying being according to a respective tap coefficient, and according to the RF carrier modulated by the phase component. The filter is arranged to combine the outputs of the taps to provide the amplified RF signal. The power amplifier uses a one bit stream which therefore has only two states (2 values), thus achieving linearity in principle. Device mismatch between taps does not lead to non-linearity or distortion. |
