| 摘要 |
PROBLEM TO BE SOLVED: To provide an FSK (Frequency Shift Keying) receiver, wherein correction of a DC offset component, which may be generated due to transmitting and receiving frequency deviations, is suitably and quickly applied to a multi-valued FSK signal. SOLUTION: In the execution of DC offset correction from an average value (center value) between a maximum value and a minimum value in carrier frequency deviations, sample values P1 to P9 are input like (a), a maximum value is updated like (d), a minimum value is updated like (e), and when a difference between the maximum value and the minimum value is less than a predetermined value, e.g. 1,500 Hz as shown in (f), correcting operation is stopped, and when the difference is the predetermined value and more, the correcting operation is performed as shown by P3 to P3' in (a). Correction is not performed by using near values in a multi-valued FSK signal and the correction is performed only when a real maximum value and a real minimum value are obtained, thereby a frequency deviation can be accurately detected and suitable offset removal can be performed. Long-time monitoring of signals is unnecessary, thereby quick correction can be achieved. COPYRIGHT: (C)2010,JPO&INPIT |
