摘要 |
The invention relates to a method for reducing interference in radio transmitters with feedback from the antenna end to the baseband side and to a transmitter applying the said method. In a Cartesian loop formed for the linearization of a transmitter, the levels of baseband input signals (s<SUB>I2</SUB>, s<SUB>Q2</SUB>) to a modulator are measured and the attenuation of a level control unit ( 210 ) following the modulator ( 203 ) is adjusted until the modulator input signal levels are sufficiently above the noise level. The adjustment may be carried out as a one-time procedure during the manufacturing process or repeatedly during the operation of the device. By means of the invention, the noise level of the output signal of a linearized transmitter can be made lower than in known transmitters. Moreover, the transmitter may utilize a cheaper and, from the point of view of manufacturing, easier 4modulator than known transmitters.
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