Abstract: In a high-frequency signal level detection apparatus for detecting an inputted signal level of a high-frequency signal, an AGC circuit executes an AGC on an intermediate frequency (IF) signal obtained by converting a frequency of a received high-frequency signal, using an RFAGC value and an IFAGC value for controlling gains of the high-frequency signal and the IF signal, respectively, based on the IF signal so that an output level of the IF signal is substantially constant. A controller previously measures first and second relational data, indicating an RFAGC value and an IFAGC value relative to the inputted signal level of the received high-frequency signal, respectively, measures the RFAGC and IFAGC values when a high-frequency signal to be measured is received, and detects the inputted signal level of the received high-frequency signal using the measured first and second relational data based on the measured RFAGC and IFAGC values.

Abstract: In a high-frequency signal level detection apparatus for detecting an inputted signal level of a high-frequency signal, an AGC circuit executes an AGC on an intermediate frequency (IF) signal obtained by converting a frequency of a received high-frequency signal, using an RFAGC value and an IFAGC value for controlling gains of the high-frequency signal and the IF signal, respectively, based on the IF signal so that an output level of the IF signal is substantially constant. A controller previously measures first and second relational data, indicating an RFAGC value and an IFAGC value relative to the inputted signal level of the received high-frequency signal, respectively, measures the RFAGC and IFAGC values when a high-frequency signal to be measured is received, and detects the inputted signal level of the received high-frequency signal using the measured first and second relational data based on the measured RFAGC and IFAGC values.

Abstract: An antenna switch apparatus and a switching method thereof including an antenna-input for cable broadcasting and an antenna-input for terrestrial broadcasting and satellite broadcasting, always receiving an OOB signal, and freely selecting one of a cable broadcasting channel and a terrestrial broadcasting channel or a satellite broadcasting channel is provided. In the antenna switch apparatus and the switching method, the terrestrial broadcasting signal is input to a select means, the cable broadcasting signal is split by a split means and the signals are input to an OOB tuner and the select means, then a signal selected by the select means is input to an A/D tuner. With this arrangement, one of the signal of the cable broadcasting channel and the terrestrial broadcasting channel or the satellite broadcasting is selected while keep receiving the OOB signal.

Abstract: An 8VSB decoder detects whether or not a digital tuner can tune in to a broadcasting signal on a selected channel, and a channel selection frequency control portion shifts, when it is detected that the broadcasting signal on the selected channel cannot be tuned in to, PLL data to the high frequency side or the low frequency side and outputs the PLL data to the digital tuner.