Polar transmitter having frequency modulating path with interpolation in compensating feed input and related method thereof

A reference phase generator for generating a reference phase output, comprising:

• a resampling circuit, arranged for receiving a modulating frequency command word (FCW) input at a first clock, and resampling said modulating FCW input by a second clock to produce a plurality of samples;
• a first accumulator, coupled to said resampling circuit, said first accumulator arranged for accumulating said samples according to said second clock to generate a first accumulated result;
• and
• a sampler, coupled to said first accumulator, said sampler arranged for sampling said first accumulated result according to a frequency reference clock, and accordingly generating a sampled result, wherein said reference phase output is updated according to at least said sampled result.

A frequency modulating method for generating a frequency modulated clock, comprising:

• utilizing a direct feed input for directly modulating frequency of an oscillator;
• utilizing a compensating feed input for compensating effects of said frequency modulating on a phase error;
• resampling said compensating feed input by a down-divided clock to produce a plurality of samples, wherein said down-divided clock is an integer edge division of said oscillator;
• and
• sampling said samples by a frequency reference clock.

A method for generating a reference phase output, comprising:

• receiving a modulating frequency command word (FCW) input at a first clock, and resampling said modulating FCW input by a second clock to produce a plurality of samples;
• accumulating said samples according to said second clock to generate a first accumulated result;
• and
• sampling said first accumulated result according to a frequency reference clock, and accordingly generating a sampled result, wherein said reference phase output is updated according to at least said sampled result.