Application of Multi-Frequency Modulation (MFM) for High-Speed Data Communications to a Voice Frequency Channel
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
Pagination or Media Count:
Multi-Frequency Modulation MFM has been developed at NPS using both differential quadrature-phase-shift-keying DQPSK and differential-quadrature- amplitude-modulation DQAM encoding formats. Previous applications of these encoding formats were on industry standard computers PC over a 16-20 kHz channel. This report discusses the implementation of MFM to a voice frequency channel of 200-3400 Hz, for possible future use with high-speed modems over switched telephone networks. Research and testing for this report included the DQPSK and differential 16-quadrature-amplitude-modulation D16-QAM encoding formats implemented on PCs. Experimental results of the implemented MFM signal were comparable to theory with acceptable bit error rates for input signal-to-noise ratios SNR of 15 dB and higher.
- Voice Communications