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Methods of loop bandwidth calibration and phase noise cancellation circuits in a fractional-n pll with aspecial switching charge pump circuit to reduce the leakage current, o/p noise spur and phase noise
Methods of loop bandwidth calibration and phase noise cancellation circuits in a fractional-n pll with aspecial switching charge pump circuit to reduce the leakage current, o/p noise spur and phase noise
The present invention provides a fractional-N PLL frequency synthesizer (100) with phase noise cancellation (7) and loop band width calibration circuit (2). The system for loop bandwidth calibration and phase noise cancellation in a PLL synthesizer (100), the system comprising: a phase frequency detector (13) operatively connected to a charge pump circuit (1); a loop filter operatively connected to the charge pump circuit(1); an oscillator operatively connected to the loop filter; wherein the charge pump circuit connected to a loop bandwidth calibration circuit (2) for compensating the gain variation in the oscillator and a phase noise cancellaltion circuit (7) for reducing the noise in the synthesizer (100); wherein the charge pump circuit (1) is operatively connected to an optimum code generator for generating a control bit for loop bandwidth calibration and noise cancellation circuit.
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