Patent ID: 7302021

Claim:
A digital broadcast receiving apparatus for amplifying a digital modulated signal wave propagated through air with gain automatically adjusted to have a predetermined amplitude, and demodulating the digital modulated signal wave to a digital signal, the digital broadcast receiving apparatus comprising: tuner means for frequency-converting the digital modulated signal wave into a first modulated signal; first automatic gain control amplification means for controlling gain of said tuner means to make a level of the first modulated signal at a first predetermined level; A/D conversion means for converting, analog to digital, the first modulated signal into a second modulated signal; demodulation means for demodulating the second modulated signal into a first demodulated digital signal; and second automatic gain control amplification means for amplifying a level of the first demodulated digital signal by following frequency fluctuations thereof to be at a second predetermined level, and generating a second demodulated digital signal, wherein said first automatic gain control amplification means controls amplification of the digital modulated signal wave by following frequency fluctuations thereof that are smaller than a first predetermined frequency for generation of the first modulated signal, and said second automatic gain control amplification means amplifies the first demodulated digital signal by following frequency fluctuations thereof under a second predetermined frequency that is larger than the first predetermined frequency, and generates the second demodulated digital signal.