Selective-calling radio receiver using direct conversion method

1. Field of the Invention A selective-calling radio receiver using the direct conversion method is provided, which commonly uses a VCO and its neighboring component for different frequency bands. This receiver is comprised of (a) a PLL frequency synthesizer for generating an initial local signal; (b) an orthogonal converter for orthogonally converting a digitally-modulated received signal to a combination of first and second baseband signals having a phase difference of 90° using the initial local signal, the orthogonal converter including (b-1) a frequency multiplier for multiplying the initial local signal by a variable multiplication factor to produce a multiplied initial local signal, (b-2) a first phase shifter for producing first and second local signals having a phase difference of 90° from the multiplied initial local signal, (b-3) a first frequency mixer for mixing the first local signal with the received signal to produce the first baseband signal, and (b-5) a second frequency mixer for mixing the second local signal with the received signal to produce the second baseband signal; and (c) an orthogonal-converter controller for controlling a characteristic of the orthogonal converter according to a frequency of the received signal.