| 摘要 |
<p>It is an object of the present invention to measure a reception level with high accuracy if a Doppler frequency is increased and the variation in phase becomes large. Approximate-line estimating means 2 linearly approximates signal amplitudes of a demodulated data stream by time interval set in accordance with an estimated Doppler frequency. Phase-rotation estimating means 3 estimates the amount of phase rotation based on the approximate line. Doppler-frequency estimating means 4 estimates a Doppler frequency based on the amount of phase rotation. Data delaying means 5 delays the demodulated data stream by time necessary for the approximate-line estimating process. Reception signal power estimating means 6 estimates reception signal power based on the approximate line. Noise-power estimating means 7 determines the difference in signal amplitude between the demodulated data stream and the approximate line as a noise component, and estimates noise power. Averaging means 8 outputs a measured reception level per time slot based on the estimated power level of the reception signal power estimating means 6 and the noise-power estimating means 7. <IMAGE></p> |
