Oscillators – Automatic frequency stabilization using a phase or frequency... – Particular error voltage control
Reexamination Certificate
2006-02-28
2006-02-28
Le, Dinh T. (Department: 2816)
Oscillators
Automatic frequency stabilization using a phase or frequency...
Particular error voltage control
C331S025000, C327S157000, C327S558000, C327S344000
Reexamination Certificate
active
07005929
ABSTRACT:
A loop filter for a frequency synthesizer provides a lower frequency pole with a smaller capacitor than conventional filters. The loop-filter comprises a resistor and a smaller capacitor in a series-feedback path, and a transconductor to sense a voltage across the resistor to either source or sink additional current proportional to the sensed voltage. The transconductor and the smaller capacitor may provide a larger capacitance. The loop filter also may comprise an operational amplifier having the smaller capacitor and the resistor in the series-feedback path to receive pulses from a charge pump. The filter may integrate the pulses and may generate a control voltage related to a width of the pulses.
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Shu, Keliu, et al., “2.4-GHz monolithic fractional-N frequency synthesizer with robust phase-switching prescaler and loop capacitance multiplier”,IEEE Journal of Solid-State Circuits, 38(6), (Jun. 2003), 866-875.
Shu, Keliu, et al., “A 16mW, 2.23-2.45GHz fully integrated Sigma Delta PLL with novel prescaler and loop filter in 0.35 mu m CMOS”,2003 IEEE Radio Frequency Integrated Circuits(RFIC)Symposium. Digest of Papers, Philadelphia, Pennsylvania, Jun. 8-10, 2003, 181-184.
Intel Corporation
Le Dinh T.
Schwegman Lundberg Woessner & Kluth P.A.
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