RADIO RECEIVER AND RADIO TRANSMITTER

摘要

PROBLEM TO BE SOLVED: To use a radio frequency circuit used for the reception of ground signals also for the reception of satellite signals by performing the frequency lowering conversion of first or second output signals and making a succeeding composite processing possibly by a mixing circuit. SOLUTION: An UHF synthesizer 603 supplies the output signals of the frequency range of 1545-1555MHz at the interval of 41.67kHz under the control of a microcontroller 405. Resultant first intermediate frequency signal are passed through a mode switch 607 and the mode switch 607 is switched to an IRIDIUM front end RF stage indicated by a broken line in the case of an IRIDIUM mode. Then, a second mixer 608 supplied with the local oscillator signals of 58MHz lowering-converts the first intermediate frequency signals and outputs the second intermediate frequency signals of 13MHz. The second intermediate frequency signals generated as a result are supplied to the base band part of a radio telephony equipment and supplied to the succeeding composite processing.