Modems for mobile communications-applications of modern technology

TRL Technology Ltd have, over the past 2 years, been under contract to INMARSAT to produce a combined modem, capable of operating as any of the three modem types within the system, in order to verify the INMARSAT-M System Definition Manual (SDM); the specification. TRL´s involvement has centred on all aspects of the modem(s). The authors summarise the main problem areas for the modem(s) and give some solutions to them. These have centred on modern DSP techniques and processes which have been implemented in hardware. Performance has been verified to the SDM requirements