Hitachi, Ltd.

Gen'ichi Ishii

Tomoaki Ishifuji

Shuichi Adachi

Communication equipment in a slow frequency hopped communication system employing a multi-level quadrature modulation carries out the AGC operation of a receiver amplifier and the operation of synchronizing the received frequency with a carrier frequency during reception of a first field of a preamble field of a communication frame when the carrier is unmodulated, completes the timing recovery of a received symbol and the synchronization with the timing during reception of a second field of the preamble field of the communication frame when the phase of the carrier is changed every symbol time, and thereafter, modulates an information signal in an information transfer field subsequent to the preamble field of the communication frame.

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Hachioji, Japan

Gen'ichi Ishii