| 摘要 |
PROBLEM TO BE SOLVED: To discriminate city noise from normal carrier reception and to correctly detect a dead channel by comparing the reception level of a measured channel with that of an interleaving frequency. SOLUTION: When a capacitor 2 and a variable capacitor and connected in parallel, output frequency of an oscillator 5 is set to constant nearer to the interleaving frequency of desired wave. At first, measurement is executed by the channel of desired wave, a switch is turned on when the reception level is higher than a stipulated value and the reception level in the interleaving frequency between the channel and an adjacent channel is measured. When the reception level in the interleaving frequency is in almost the same level as that of the desired channel, it is judged that the reception level of the channel exceeds the stipulated value by city noise and the channel is assigned to as the dead channel. When the reception level in the interleaving frequency is lowere, the channel is considered to be the one under usage. |
