Patent ID: 6714084
Filing Date: 2004-03-30
Classification: H03K,H03L

Abstract:
A frequency synthesis circuit comprising:a noise-shaping quantizer responsive to a plurality of input bits for shaping error signals resulting from a quantization conversion such that most of errors occurs at a higher frequency, and a digitally controlled oscillator coupled to an output of the noise-shaping quantizer having an output frequency responsive to the output of the noise-shaping quantizer, wherein the digitally controlled oscillator comprises: a plurality of digitally controlled delay devices coupled in cascade, wherein each of the delay devices has two input ends, two output ends, a coarse control input end, and a fine control input end, wherein a first one of the delay devices also receive output signals fed back from a last one of the delay devices at the two input ends, wherein the coarse control input end receives a coarse control signal to select coarse frequencies, and the fine control input end receives a fine control signal from the noise-shaping quantizer to adjust the coarse frequencies into fine frequencies.