| 摘要 |
The method comprises a variation of the amplitude of a carrier other than the amplitude modulation (AM). The modulated signal s(t) is obtained on the basis of two signals: the first signal which is used to determine the instantaneous phase of an analytic signal s(t)-jsasterisk(t), where j is the imaginary unit, associated with the modulated signal s(t) in a manner that the instantaneous phase is in the vicinity of a constant close to the instantaneous phase, and the second signal which is of variable amplitude used to determine the instantaneous amplitude of the analytic signal associated with the modulated signal. The two signals are produced by signal processing effected on a modulating signal e(t), which includes the computing in real time of the Hilbert transform of the modulating signal. An amplifier stage operated in class C, class E, or class F of a transmitter is implemented by use of an insulated-gate field-effect transistor (IGFET), which receives at its carrier input the first signal, which is of variable phase, to determine the phase of the modulated signal, and at its modulation input the second signal, which is of variable amplitude, to determine the amplitude of the modulated signal. The modulated signal obtained at the output of the amplifier operated in class C is a signal with a single side band (SSB). The analytic signal associated with the modulating signal is given by e(t)-jeasterisk(t). The modulated signal s(t) can be generated with a sufficient precision as a product of the two signals. The generation of the modulated signal comprises a linear filtration. The second signal depends in a nonlinear fashion on the instantaneous amplitude attained by the analytic signal associated with the modulated signal. The processing of signa l utilized for generating the first signal and/or the second signal comprises a digital signal processing, or analog signal processing. The obtained modulated signal is a signal with single side band and removed carrier, or a reduced carrier, or a signal with discrete analog modulation with or without sub-carrier. A device (claimed) for implementing the method (claimed) comprises an amplifier operated in class C, class E, or class F.
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