Low noise converting apparatus

摘要

Radio waves from a plurality of satellites can be received by one antenna, thereby realizing a miniaturization and a reduction of costs. A reception signal of a horizontally polarized wave and a reception signal of a vertically polarized wave from one satellite are amplified by low noise amplifiers 21 and 22. A reception signal of a horizontally polarized wave and a reception signal of a vertically polarized wave from another satellite are amplified by low noise amplifiers 23 and 24. One of the low noise amplifiers 21 to 24 is selected in accordance with the polarized wave and the satellite and the signal from the selected low noise amplifier is supplied to a low noise amplifier 4 through a coupling circuit 3. An output of the low noise amplifier 4 is frequency converted by a local oscillator 7 and a mixer 6. In this manner, a plurality of coupling circuits needed in a conventional apparatus are constructed by one coupling apparatus 3, thereby realizing the miniaturization and the reduction of the costs and enabling the other portions to be used in common.