Patent ID: 6195400
Filing Date: 2001-02-27
Classification: H04L

Abstract:
A two-mode demodulating apparatus comprising:a linear reception demodulating circuit;a non-linear reception demodulating circuit;a local oscillator; anda control section for controlling to selectively operate in said linear reception demodulating circuit and said non-linear reception demodulating circuit by selecting a mode, whereinsaid control section controls to place said linear reception demodulating circuit in an operative state when a receiving signal is a linear signal, and place said non-linear reception demodulating circuit in an operative state when said receiving signal is a non-linear signal,said local oscillator including:a variable oscillated frequency local oscillator for generating a first local signal having a first oscillated frequency when said receiving signal is said linear signal, and generating a second local signal having a second oscillated frequency different from said first oscillated frequency of said said first local signal, said linear reception demodulating circuit including:a first frequency converting unit for frequency-converting said received signal into a low-frequency signal using said first local signal from said variable oscillated frequency local oscillator; anda linear reception demodulating process unit for performing linear reception demodulating process on an output of said first frequency converting unit,said non-linear reception demodulating circuit including:a second frequency converting unit for frequency-converting said received signal into a low-frequency signal using said second local signal from said local oscillator;a variable-band filtering unit for allowing a signal in a desired band contained in an output of said second frequency converting unit to pass therethrough; anda non-linear reception demodulating process unit for performing a non-linear reception demodulating process on an output of said filtering unit.