A heat exchanger comprising a core containing inlet manifolds, outlet manifold and interconnecting channels and having a heat-transfer surface. The combination of which defines two or more object planes. A little space is required for mounting the sensor chip having the magneto-resistive element and therefore downsizing can be attained. The received signals are multiplexed, digitally converted, digitally beamformed, and then transferred to a digital receiver. Each of the macroblock decoding units, when decoding the corresponding one of macroblock groups, uses the macroblock decoding information that has been generated for the other macroblock group. Again, if the designated link region has only one link destination, an image at the link destination is set as display data, while if the designated link region has a plurality of link destinations, all the link destinations may be displayed in a list.