| 摘要 |
PURPOSE:To reduce modulation distortion by applying pulse width modulation to a low frequency signal, applying power amplification to the signal and applying a low frequency signal obtained through an energy storage circuit from the output to a power amplifier to be modulated via a low frequency transformer. CONSTITUTION:After a low frequency signal A undergoes pulse width modulation by a pulse width modulator 4, the signal is amplified by the modulation amplifier 1. The output of the amplifier 1 is fed to the energy storage circuit 5. Then an output voltage of the storage circuit 5 is boosted by a low frequency transformer 9. The output of the transformer 9 is superimposed on a power supply voltage V fed to a modulated power amplifier 12 via a modulation choke coil 11. Since the signal is subjected to amplitude modulation, the effect of a pulse due to stray capacitance is reduced and the modulation distortion is reduced.
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