| 摘要 |
A digital phase and amplitude modulator with a code conversion circuit having several digital inputs able to receive digital data and the same number of outputs supplying code converted digital data, a generator of at least one carrier having at least one phase control input and at least one output supplying at least one carrier having a given phase, a digital-analog converter comprising a first stage formed by logic gates having two inputs and one output, one input each of the logic gates being connected to one of the outputs of the code conversion circuit, while the other input is connected to one of the outputs of the generator, and a second stage formed by the same number of transistors as there are logic gates. The modulator also comprises a compensating circuit constituted by at least one supplementary logic gate located in the first stage of the converter, with an input connected to one of the outputs of the code conversion circuit and an output, as well as at least one supplementary transistor located in the second stage of the converter. For at least one of the modulated output voltages, the compensating circuit brings about a displacement to its mean value bringing the latter to the level of the mean value of the other voltages, the modulated output signal then being formed by voltages having different phases and amplitudes, but all centered on a common mean value. |
