| 摘要 |
PURPOSE: An improved multifrequency band receiving device and a method thereof are provided to simplify a high frequency stage, to decrease the number of element, and to improve an ability of a receiving device by arranging numerous frequency bands in order of low frequency and using an intermediate frequency of a previous stage at the next stage again. CONSTITUTION: A filter(21) gets a wanted frequency component by filtering signal received through an antenna, and a wideband low noise amplifier(22) amplifies the wanted frequency component. A first mixer(24) mixes the amplified frequency component with an output signal of the first local oscillator(23). Through this process, the first down conversion is performed. A low pass filter(25) passes a fixed band signal from the output signal of the first mixer(24), and a divider(26) divides the output signal of the low pass filter(25) into two signals. At this time, two signals are same each other. A low pass filter passes only an intermediate frequency of one signal between two signals, and only a fixed band of the other signal is amplified by a band amplifier(29), and a filter(30) passes only a fixed band from the fixed band amplified by the band amplifier(29). After this, the second mixer(32) mixes the output signal of the filter(30) with an output signal of the second local oscillator(31). Through this process, the second down conversion is performed.
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