| 摘要 |
An AM signal transmitter for generating an amplitude modulated carrier comprises a voltage-increasing stage and a power-increasing stage. The voltage-increasing stage includes a pulse width modulator, responsive to an input modulation signal, for producing a pair of high frequency pulse trains which are modulated in width in a complementary fashion. The pair of pulse trains are respectfully fed to a pair of switching and amplifying elements arranged in push-pull fashion. The output of the switching and amplifying elements is processed through a low pass filter to eliminate high frequency components, and is stepped up in voltage by processing through a voltage step-up transformer. The output of the voltage step-up transformer is then fed to the power stage of the AM signal transmitter, which include a power amplifier. Both the power amplifier and the switching and amplifying elements can be powered from a single power source. Other embodiments of the invention can be realized.
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