Patent ID: 8179948

Claim:
A radio signal demodulating device receiving as a radio signal in which the amplitude of an information signal, in which known pilot signals are multiplexed, is modulated in proportion to the time change of frequency of a carrier wave, the radio signal demodulating device comprising: a frequency converting unit receiving said radio signal by a plurality of antennas and converting frequency of said radio signal received in each of said antennas into predetermined frequency so as to output as output signals; a signal combining unit multiplying each of said output signals obtained by said frequency converting unit by a weight factor so as to output the sum thereof as a combined output signal; a first pilot signal extracting unit extracting said pilot signals multiplexed in said output signals obtained by said frequency converting unit; a second pilot signal extracting unit extracting said pilot signals multiplexed in said combined output signals obtained by said signal combining unit; a first pilot orthogonal signal generating unit generating a signal orthogonal to a first pilot signal obtained by said first pilot signal extracting unit so as to output the signal as a first pilot orthogonal signal which is a complex signal; a second pilot orthogonal signal generating unit generating a signal orthogonal to a second pilot signal obtained by said second pilot signal extracting unit so as to output the signal as a second pilot orthogonal signal which is a complex signal; a first error signal generating unit outputting an error of said combined output signal with respect to said known pilot signal as a first error signal by using said second pilot orthogonal signal and a reference signal having the same frequency as said pilot signal; and a first weight factor updating unit calculating said weight factor used in said signal combining unit by using said first pilot orthogonal signal and said first error signal obtained by said first error signal generating unit.