| 摘要 |
A method for reducing out-of-band and spurious emissions of AM transmitters in digital operation includes providing an amplitude signal and an RF-P signal from a digital modulation signal. The RF-P signal is tapped in the RF branch and the tapped signal is passed through a Gaussian filter in a separate branch, the Gaussian filter having a linear phase. The filtered RF-P signal is fed to an envelope detector to detect amplitude variations. The detected amplitude variations are combined as a correction signal with the amplitude signal in a multiplier in the A branch to produce a corrected amplitude signal. The corrected amplitude signal is fed to the linear input of the transmitter output stage and multiplied by the RF-P signal.
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