Injection locking LC dividers for low power quadrature generation

The trade off between phase noise and quadrature accuracy, typical of coupled voltage controlled oscillators, is broken if injection locking dividers are used for I and Q generation. Based on the general behavioral modeling of regenerative frequency dividers, this paper derives analytical expressions for locking band and phase deviation from quadrature. An injection locking quadrature generator, embedded in a 0.18 /spl mu/m CMOS direct conversion receiver, shows 24% frequency locking range while drawing 4 mA. The phase deviation from quadrature measured on down-converted signals is 0.8/spl deg/.

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