A performance comparison and evaluation of two GMSK radio modem designs: a DSP algorithm versus a discreet component implementation

The RAM Mobile Data nationwide packet radio system utilizes portable and mobile access devices to allow subscribers to communicate using short bursts of data. Cost-effective approaches for implementation of a GMSK modem that would match the operational requirements of the specified wireless protocol of RAM network are compared. The DAP modem implementation is a useful approach to consider in evolving designs and in experiments involving rapid iterations of sensitive parameters, such as filter bandwidths. Also, adaptive channel equalization routines can be readily added. The discrete modem design offers a minimum of parts and a low cost solution using widely available components. Significant board shrinkage through the use of gate arrays or programmable logic arrays is a viable option due to the mostly digital hardware implementation