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Systems with frequency hopping
Jelínek, Martin ; Říha, Kamil (referee) ; Pust, Radim (advisor)
This bachelor´s thesis deals the systems, which use the Frequency Hopping (FH). The brief history of frequency hopping and its development together with Adaptive Frequency Hopping technology (AFH) is introduced. The general function principle of AFH, which differs AFH from FH, is described. Advantages and disadvantages of frequency hopping and its division into fast (FFH) and slow (SFH) are described next. Some of military communication systems (e.g. SINCGARS, Eritac, MRR, Panther V-EDR and next) as well as some of commercial systems (e.g. worldwide-spread Bluetooth system) are introduced. Mentioned systems use digital modulations, three of basic digital modulations are demonstrated (ASK - Amplitude Shift Keying, FSK - Frequency Shift Keying and PSK - Phase Shift Keying). Basic types of used spectrum spreading (FHSS, DSSS, OFDM) are mentioned next. The FHSS type of spectrum spreading is described in more detail, because the spectrum spreading is done by frequency hopping. Particular systems contain error control of radio transmission of information, which is realized by FEC (Forward Error Correction) and ARQ (Automatic Repeat Query) techniques. Practical part of the bachelor´s thesis demonstrates, with usage of Matlab programme, adaptive frequency hopping function (AFH) during communication of Master-Slave devices, where more systems are active. This causes the interference of the communication. This interference is caused by static and dynamic jammers, that work in the same band as the Master-Slave devices.
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Systems with frequency hopping
Jelínek, Martin ; Říha, Kamil (referee) ; Pust, Radim (advisor)
This bachelor´s thesis deals the systems, which use the Frequency Hopping (FH). The brief history of frequency hopping and its development together with Adaptive Frequency Hopping technology (AFH) is introduced. The general function principle of AFH, which differs AFH from FH, is described. Advantages and disadvantages of frequency hopping and its division into fast (FFH) and slow (SFH) are described next. Some of military communication systems (e.g. SINCGARS, Eritac, MRR, Panther V-EDR and next) as well as some of commercial systems (e.g. worldwide-spread Bluetooth system) are introduced. Mentioned systems use digital modulations, three of basic digital modulations are demonstrated (ASK - Amplitude Shift Keying, FSK - Frequency Shift Keying and PSK - Phase Shift Keying). Basic types of used spectrum spreading (FHSS, DSSS, OFDM) are mentioned next. The FHSS type of spectrum spreading is described in more detail, because the spectrum spreading is done by frequency hopping. Particular systems contain error control of radio transmission of information, which is realized by FEC (Forward Error Correction) and ARQ (Automatic Repeat Query) techniques. Practical part of the bachelor´s thesis demonstrates, with usage of Matlab programme, adaptive frequency hopping function (AFH) during communication of Master-Slave devices, where more systems are active. This causes the interference of the communication. This interference is caused by static and dynamic jammers, that work in the same band as the Master-Slave devices.
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