| 摘要 |
PURPOSE:To lock the titled device for a short time even if transmission frequency different from that of semiactive homing guide is used at the time of active homing guide by setting up searching frequency in accordance with objective Doppler frequency. CONSTITUTION:Objective speed information 17 from a Doppler frequency tracking circuit 5 is stored in a storage circuit 16 while being updated by the newest contents momently. An arithmetic circuit 14 calculates the objective Doppler frequency on the basis of the objective speed information 17 stored in the storage circuit 16 and transmission frequency information 13 from a transmitter 10. Receiving the objective Doppler frequency, a searching frequency setting circuit 15 sets up searching frequency in accordance with the objective Doppler frequency. Consequently, a narrow band tracking filter 6 locks the objective Doppler frequency for a short time. Thus, the titled device can be locked for a short time even if the transmission frequency different from that of the semiactive homing guide is used at the time of active homing guide. |
