Energy efficient highway addressable remote transducer soft modem

A method for modulating and transmitting an analog signal comprising a highway addressable remote transducer message, said method comprising:

• converting said highway addressable remote transducer message into a serial data bit stream comprising binary information by a parallel to serial converter;
• checking a value of said binary information of said serial data bit stream by a phase coherent frequency shift keying modulator;
• setting a phase change of a carrier signal to a first frequency when said value of said binary information is 1 and setting said phase change of said carrier signal to a second frequency when said value of said binary information is 0, by said phase coherent frequency shift keying modulator;
• accumulating incremental phase change data by continuously adding said phase change of said carrier signal, by said phase coherent frequency shift keying modulator;
• comparing said accumulated phase change data with a plurality of sine values from a predetermined sine value phase table by said phase coherent frequency shift keying modulator;
• selecting one of said sine values corresponding to said accumulated phase change data from said predetermined sine value phase table by said phase coherent frequency shift keying modulator;
• and
• converting said selected one of said sine values into said analog signal by said phase coherent frequency shift keying modulator for transmission of said highway addressable remote transducer message.