Fast Fourier Transform of Frequency Hopping Spread Spectrum in Noisy Environment

摘要

Frequency hopping spread spectrum (FHSS) systems have traditionally been applied in low data rate applications where the received signal can be considered narrow band. In this paper we have discussed a synchronous coherently detected FHSS/BPSK system. Pseudonoise sequence generator has been implemented to select the frequencies for transmission or reception. We have investigated the spectral characteristics of both spread and nonspread BPSK waveforms. We have analyzed and simulated these systems with several variations by taking the Fast Fourier Transform (FFT) of FHSS with original binary sequence and with noisy signal. The simulated results have shown that a signal lingering at a predefined frequency for a short period of time limits the possibility of interference from another signal source generating radiated power at a specific hop frequency.