A radio transceiver includes a charge pump formed within a local oscillator that adjusts a voltage input to a voltage-controlled oscillator in a manner that flattens a response curve for small changes in voltage due to a variety of effects including channel length modulation. Thus, a local oscillation tends to provide a greater degree of stability. More specifically, the charge pump of the transceiver includes a pair of feedback circuits that source an additional amount of current into a filter to slightly increase a voltage input to the voltage-controlled oscillator in response to small upward changes in output voltage levels (input with respect to the voltage-controlled oscillator). Similarly, when the output voltage level drops slightly, a second feedback circuit causes a small amount of current to be sinked from the output node thereby slightly decreasing the input voltage to the voltage-controlled oscillator. Thus, the inventive charge pump produces better matching between IUP and IDOWN thus operating to produce a response curve that tends to be flatter in response to small voltage changes due to circuit conditions.

 
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> Tuner receiving system, control unit for receiving radio waves by using tuner, storage medium from which data can be read out by using computer, and method of receiving radio waves by using tuner

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