| 摘要 |
A dual loop feed forward amplifier and method of amplification. The dual loop feed forward amplifier contains at least two amplification stages that introduce unwanted intermodulation products into the output signal. A spreading tone is introduced to the RF signal in between the first and second amplification stages. The spreading tone is created by a bi-phase modulator that spreads an input tone in accordance with a spread PN-code. After the spreading tone is amplified by the subsequent stages of the feed forward amplifier, the spreading tone is despread by the same spread PN-code. The resulting output tone is mixed with the original in put tone. The output of the mixer is then filtered to remove the unwanted spurious products produced by the mixer. The feed forward amplifier is then actively adjusted by a computer controller to reduce any difference between input tone and the output tone until a desired signal to -interference ratio is obtained.
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