| 摘要 |
PROBLEM TO BE SOLVED: To obtain a data clock phase (symbol judgment point) accurately. SOLUTION: Input GMSK (Gaussian filtered minimum shift keying) modulation signals are changed 14 into digital series, and they are orthogonally converted 14 to obtain the adjacent phase, further the phase differences are calculated in sequence to obtain 15 their instantaneous frequency column. Each of instantaneous frequencies is squared, and the squared column is subjected to discrete Fourie transform by the symbol frequency. Then the clock phase of the modulated data is obtained 16 from the inverse tangent of its real and imagninary parts, and the phase is used to demodulate 18 the data, then an ideal signal is generated 21 by using the demodulated data. Further, an error of carrier frequency is found out on the basis of the change of phase difference between the ideal signal and the inputted digital series, and the initial phase is obtained 22 by using its intercept. |
