Patent ID: 7796962

Claim:
A digital demodulating apparatus comprising: a plurality of circuit elements constituting a tuner that selects a frequency band out of a plurality of frequency bands and receives the signal in the selected frequency band, each signal being constituted by a plurality of carrier waves distributed in the frequency band; a demodulator that demodulates a signal output from the tuner; a first measuring unit that measures the intensity of noise contained in the signal from the tuner due to an interfering wave contained in the signal received by the tuner, on each carrier wave distributed in the selected frequency band; a distribution estimating unit that estimates at least one of the distribution of interfering waves in the selected frequency band, and the distribution of interfering waves in a frequency band neighboring the selected frequency band, on the basis of the distributions of noises in the selected frequency band measured on each carrier wave by the first measuring unit; a noise change deriving unit that derives a change in the intensity of noise to be contained in the signal from the tuner, to the power to be supplied to one of the circuit elements, on the basis of the distribution of interfering waves estimated by the distribution estimating unit, and the intensity of noise measured by the first measuring unit; and a power updating unit that updates the value of the power to be supplied to the circuit element within a range in which the intensity of noise to be contained in the signal from the tuner is less than a noise reference value, on the basis of the change in the intensity of noise to the power to be supplied to the circuit element, derived by the noise change deriving unit.