1 and time t 2 the reception sensitivity of the image data carried by tv broadcast waves is generally favorable it is understood that this is because the portable terminal 9 is for example in the tv broadcast reception area 13 shown in fig1 however after time t 2 the above reception sensitivity decreases generally step by step after time t 3 it is observed that the reception sensitivity is in a degraded state it is understood that this is because the portable terminal 9 has moved between time t 2 and time t 3 for example from the tv broadcast reception area 13 to the data distribution reception area 11 shown in fig1 fig8 is a chart showing the relationship between time and the reception sensitivity of image data carried by tv broadcast waves received by the portable terminal 9 of fig6 and the relationship between time and the reception sensitivity of image data carried by data communication waves received by the portable terminal 9 of fig6 fig8 a shows the relationship between time and the reception sensitivity of image data carried by tv broadcast waves received by the portable terminal 9 as described in fig7 also fig8 b shows the relationship between time and the reception sensitivity of image data carried by data communication waves received by the portable terminal 9 of fig6 in fig8 b from.