Patent ID: 6487242
Filing Date: 2002-11-26
Classification: H04L

Abstract:
A communications system comprising:a computer developing a data stream for transmission; a radio modem comprising: a) a VCO controller coupled to said computer to receive said data stream, said VCO controller developing a VCO control signal by GMSK waveform synthesis, wherein said VCO controller includes: ROM memory storing a plurality of waveform maps; a counter coupled to said ROM memory and capable of developing a sequence of ROM addresses to provide a sequence of ROM memory outputs; a temporal bit generator responsive to said data stream, said temporal bit generator developing a next bit Nb, a current bit Cb, and a past bit Pb from said data stream; control circuitry to develop a digital waveform signal from a selected waveform map in said ROM memory, said control circuitry being responsive to said Nb, Cb, and Pb bits and said sequence of ROM memory outputs; and a DAC responsive to said digital waveform signal and operative to output said VCO control signal that encodes said data stream; and b) a transmitter having a VCO portion, said VCO portion having an input responsive to said VCO control signal, said transmitter developing a modulated RF signal carrying said data stream in response to said VCO control signal; and an antenna coupled to said transmitter of said radio modem for transmission of said modulated RF signal.