Patent ID: 7035603

Claim:
A wireless transmitter for modulating a loaded data to a radio frequency signal and then emitting out, said transmitter comprising: a read only memory having a lookup table therein for storing a plurality of intermediate frequency modulation signals; a state machine for selecting a corresponding intermediate frequency modulation signal from said lookup table of said read only memory according to said loaded data, locking and storing said intermediate frequency modulation signal, and then outputting a digital intermediate frequency modulation signal, said modulation signal in said lookup table obtained by calculating an algorithm at different frequencies, and said algorithm comprises the steps of: dividing a modulated radio frequency signal into an intermediate frequency signal plus a carrier signal and a baseband signal to be expanded in trigonometric functions; expanding sine terms and cosine terms of said intermediate frequency signal plus said carrier signal in trigonometric functions; separately arranging the sine terms and cosine terms of said carrier signal to obtain coefficients respectively being two orthogonal intermediate frequency modulation signals; and sampling and storing said intermediate frequency modulation signals into said lookup table of said read only memory according to the sampling rate; at least a digital-to-analog converter connected to said state machine, said digital-to-analog converter converting said digital intermediate frequency modulation signal into an analog intermediate frequency modulation signal; at least a low pass filter for filtering said analog intermediate frequency modulation signal; and a local oscillator for generating a local oscillation signal and modulating said filtered analog intermediate frequency modulation signal to an emission frequency to obtain said radio frequency signal.