A hopping phase estimator for frequency hopped FM/BFSK signals

We proposed a hopping phase estimator to demodulate the received signals without any information with respect to hopped frequency in frequency hopping spread spectrum systems. We deal with signals modulated as frequency modulation (FM) or binary frequency shift keying (BFSK) and hopped by frequency predetermined random sequence. The received signal is demodulated through two stages such as hopped frequency tracking and hopping frequency estimation in this paper. The former is accomplished by choosing the frequency component with maximum amplitude after taking discrete Fourier transform (DFT). The latter consist of difference product and down-sampling and estimates the phase generated by hopped frequency. We obtained the probability density function (pdf) and variance performance of the proposed phase estimator and confirmed that the analysis agreed with the simulation results.