Title :
A new power efficient multi-level correlative digital FM system
Author :
Seo, Jong-Soo ; Boyd, John W G
Author_Institution :
Int. Datacasting Corp., Ottawa, Ont., Canada
Abstract :
A novel modulation technique to transmit bandlimited and intersymbol interference (ISI)-free multilevel digital signals is proposed for the use in digital radio-microwave, mobile and satellite radio systems. Emphasis is on the design of a 9.6 kb/s 4-level digital FM modem for satellite communications, especially for VSAT application. Experimental measured-eye diagrams and the power spectrum of this modem are reported. Optimization between the required signal power and bandwidth of the transmission channels could be done by selecting the number of signal levels and modulation index of the modem. A preliminary study shows that the modem technique may give better performance than coherent PSK systems, especially for low-speed data transmission where phase noise and lock-up speed of carrier recovery loop limit the system performance
Keywords :
correlators; digital communication systems; frequency modulation; microwave links; mobile radio systems; satellite relay systems; 9.6 kbit/s; VSAT; bandlimited interference-free signal; carrier recovery loop; coherent PSK systems; digital radio microwave systems; intersymbol interference-free signal; lock-up speed; low-speed data transmission; measured-eye diagrams; mobile radio systems; modem; modulation index; modulation technique; multilevel digital signals; optimisation; phase noise; power efficient multi-level correlative digital FM system; power spectrum; satellite radio systems; transmission channels; Bandwidth; Data communication; Digital modulation; Intersymbol interference; Modems; Phase noise; Phase shift keying; Power measurement; Satellite broadcasting; Satellite communication;
Conference_Titel :
Vehicular Technology Conference, 1988, IEEE 38th
Conference_Location :
Philadelphia, PA
DOI :
10.1109/VETEC.1988.195425
