| 摘要 |
<p>PROBLEM TO BE SOLVED: To attain stable operation with high performance by preventing temporary out of synchronism for reception in the radio data transmitter adopting the direct spread system spectrum communication system. SOLUTION: A switch 116 is provided to a threshold level input of a comparator 113 to select a threshold level. The switch 116 connects to the position of H at initial acquisition of synchronization and the level is set to a high threshold level and when synchronization is taken once, a control circuit 114 is used to select an L position to decrease the threshold level. Even when any hindrance is in existence between a transmitter and a receiver and the correlation value is decreased, out of synchronism hardly takes place by setting the threshold level of L level side to a lower level than L level in advance. Through the constitution above, even when the correlation value is decreased tentatively, since no out of correlation takes place, the stable operation of the comparator 113 is obtained.</p> |
