Loop filter and amplifier for improved phase margin and decreased phase noise with VCOs

摘要

A loop filter and amplifier (206) is configured to generate a control voltage (VC) by applying low gain to a correction voltage (VP) in response to an input signal (VH/L) indicating that the VCO (202) is to operate at low frequencies and applying high gain to the correction voltage in response to the input signal indicating that the VCO is to operate at high frequencies. A loop filter and amplifier (306) is configured to generate a control voltage (VC) by shifting the control voltage by an amount determined by an offset voltage (VOFF) and by adjusting the control voltage with a correction voltage (VP). An operational amplifier (310) is configured to generate a difference between the amount determined by the offset voltage and the correction voltage.