| 摘要 |
A phase modulated signal received by a selected one of a plurality of antennas is demodulated and phase error detecting means detects a phase error of each symbol of the received signal as a deviation from an ideal phase S202. An accumulator accumulates the phase errors and switching between the antennas is controlled if an accumulated value of the phase errors is equal to or greater than a predetermined value S209. By switching temporarily to a second antenna S210 when the accumulated phase error value is greater than or equal to a predetermined value, the demodulated phase of both the first antenna and the second antenna may be stored S205, S214 and the received signal strength of both antennas determined S204, S213. Thus when fading occurs, the antenna providing the better reception can be selected S215 and the correct demodulated phase plane can be loaded into the demodulator thus reducing the possibility of reception error after switching. Preferably, the phase modulated signal comprises a plurality of frames and phase errors of the respective frames are accumulated such that switching between the antennas in a next frame is controlled if an accumulated value of the phase errors is greater than a predetermined value in a predetermined slot position a frame. |
