| 摘要 |
PURPOSE: To make the time constant till established of synchronization is by providing a correlation means and a mode changeover means and deciding the establishment of frame synchronization based on the comparison result between 2nd correlation and a 2nd threshold level. CONSTITUTION: A correlation device 13 calculates the correlation between an allocated synchronization series ϕ and a sample value series of a reception signal in a calculation section with respect to sections of respective widths of search windows. When the calculation is finished, a mode changeover device 14 stops the operation of the correlation device 13 and decides whether or not the correlation value exceeds a 2nd threshold level every time the correlation device 13 reports the correlation value and grasps the detection interval of the correlation value in excess of the 2nd threshold level. When a received signal is sent for a frame period, the correlation value over the 1st threshold level is detected for plural number of times. The frame period is recognized from the detection interval of the correlation value in excess of the 2nd threshold level and a transmission rate is found out. For example, when the interval is consecutive, the mean value of the intervals is decided to be a frame period. |
