Patent ID: 6882831

Claim:
A Radio Frequency (RF) transmitter comprising: an Intermediate Frequency (IF) modulator that receives a modulated baseband signal and that produces a modulated IF signal having a non-constant envelope; a translational loop that receives the modulated IF signal and that produces a modulated RF signal having a constant envelope; an envelope time delay adjust block that receives an envelope signal corresponding to the modulated IF signal and that produces a time delayed envelope signal based upon a time delay control signal; an envelope adjust block that adjusts the modulated RF signal based upon the time delayed envelope signal to produce an envelope adjusted modulated RF signal; and a time delay calibration block that receives the envelope adjusted modulated RF signal and that produces the time delay control signal and that comprises: a down converter that converts the envelope adjusted modulated RF signal to a baseband signal; an Analog to Digital Converter (ADC) that samples the baseband signal; a Low Pass Filter (LPF) that filters the baseband signal to produce a LPF output; a Band Pass Filter (BPF) that filters the baseband signal to produce a BPF output; and a level detector and control block that receives the LPF output and the BPF output and that produces the time delay control signal based upon the LPF output and the BPF output.