Ultra Narrow Frequency Shift Keying Communication Technology

Ultra narrow frequency shift keying (UNFSK) communication technology is a kind of information modulation and demodulation method which can greatly increase the bandwidth efficiency. But the demodulation of UNFSK is a very difficult technical problem because the two frequencies representing code 0 and 1 are extremely close which can not be successfully demodulated by traditional methods. In this paper, we make use of cycle extension and notch filter to successfully demodulate the UNFSK signals, so the high bandwidth efficiency communication method will become a reality.