| 摘要 |
A radio receiver ( 30 ) comprises an ADC ( 13 ) including a clip counter. The power of digitised signals provided by the ADC ( 13 ) is estimated by a power estimator ( 31 ), and an ideal gain value is computed from the power so estimated by a gain computation device ( 32 ). Gain computation signals are fed to a gain control input of an amplifier ( 11 ) via an LPF ( 33 ). A saturation detector ( 34 ) is connected to a clip counter output of the ADC ( 13 ), and to a control input of the LPF ( 33 ). The saturation detector ( 34 ) is arranged when saturation of the ADC is detected to reduce the gain setting value by at least two steps, by which the gain of the amplifier is immediately reduced. A detector detects the Doppler frequency of signals received and accordingly determines the size of the drop in amplification which is effected when saturation of the ADC ( 13 ) is detected. The gain reduction may be 3 dB under very low Doppler shift conditions and 12 dB under very high Doppler shift conditions. |
