Patent ID: 7555274
Filing Date: 2009-06-30
Classification: H03G,H04B

Abstract:
1. A radio receiver comprising: a low noise amplifier which amplifies a radio signal; a quadrature demodulator which demodulates the amplified radio signal into a baseband signal; a variable gain amplifier which amplifies the baseband signal; an executing unit configured to execute feedback of the amplified baseband signal; and a first gain controller which controls a first gain of the low noise amplifier and a second gain of the variable gain amplifier, the first gain controller comprising, a signal intensity detector which detects an intensity of the amplified baseband signal, a gain selector which selects a preset gain from a plurality of preset gains which are set for the low noise amplifier, based on the detected intensity, a timing controller which controls timing of switching the first gain and the second gain to the selected preset gain, and a gain control signal output unit configured to output a gain control signal which controls the first gain according to the selected preset gain at a time-interval according to the controlled timing; and a second gain controller which controls the second gain if the time-interval is not longer than a present time-interval; wherein the timing controller comprises, a measurement unit configured to measure time when an intensity of a received signal crosses a threshold value, and calculate a time-interval elapsing from a previous adjacent time when the intensity of the received signal crossed a threshold value to the measured time, and a comparator configured to compare the time-interval with the preset time-interval; and the gain control signal output unit outputting the gain control signal to the low noise amplifier if the time-interval is longer than the preset time-interval.