FREQUENCY HOPPING SPREAD SPECTRUM RADIO COMMUNICATION SYSTEM

• Main Author: MATSUSHITA HISAHIRO
• Format: Patent
• Language: English
• Published: 13.10.1995
• Edition: 6
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION

PURPOSE:To improve the spreading uniformity of transmission spectrums and to eliminate radio wave interference and influence on responses by changing a transmission frequency every time even when the transmission time of one telegraphic message is less than one-frequency residence allowable time. CONSTITUTION:A PLL frequency synthesizer 5 sends out the oscillation signals of an oscillation frequency decided by control from a microcomputer 2 to a modulation means 3. In the modulation means 3, the oscillation signals are modulated by transmission data turned to a packet and the modulated signals are sent out to a transmission means 6. Then, at the time of transmitting the transmission data, when the transmission of the transmission data is completed within the prescribed frequency residence allowable time, the next transmission data are transmitted and received by the carrier waves of the frequency different from the frequency of the carrier waves of the transmission data immediately before. Since a carrier frequency to be used is changed every time a transmission telegraphic message is generated in such a manner, one specific frequency is not occupied even when the transmission telegraphic message is short and spectrum is surely performed at all times.