. 7 is a block diagram showing a block of FIG. 1 in detail;FIG. 8 is a flow chart which shows the steps which characterize the operation of the fade detector according to the embodiment of the present invention;FIG. 9 is a flow chart which shows the steps which characterize the operation of a bit amount adjuster according the embodiment of the present invention; andFIG. 10 is a sketch that shows t