| 摘要 |
A method for reducing the influence of distortion products that are formed in conjunction with the analogue-digital-conversion (14,15) of samples of an electric signal (IF), from which signal two quadrature signals (I,Q) are formed prior to the conversion process. The quadrature signals are phase modulated (16-20) prior to the conversion process and are phase demodulated (20-22) subsequent to this conversion process, by phase-shifting the signals by a value ( phi n, - phi n) which is changed randomly for each new sample. The energy content of individual distortion products is distributed over a broadband in this way. This is due to correct demodulation of the useful signal, i.e. the fundamental tone, whereas harmonics and intermodulation products will have a residual phase modulation subsequent to the phase demodulating process. <IMAGE> |
