| 摘要 |
<p>The amplitude modulator includes a pulse generator (1-3) which supplies pulses at a carrier frequency to a pulse width modulator (4) to which a modulation signal is applied from a source of modulation signals (5-9) to produce a bipolar pulse width modulated signal which then is passed through amplifiers and filters (10-12) to produce an amplitude modulated output signal. To prevent nonlinear operation, the modulation signal is modified in a correction amplifier (9) before application to the modulator (4). In a modified embodiment the output of the pulse width modulator (4) is converted into two square wave pulse trains, phase shifted relative to each other, by monostable and amplifying circuits (10-14), and the two pulse trains are combined in a transformer (15) to produce the bipolar pulse width modulated signal. Since the components of this circuit are operating in the switching mode, high efficiency operation is obtained.</p> |
